Jacketed vs. HardCast (barrel wear)

[Flexmoney]

The reason I asked you to start a new and specific thread (which...you were a bit off on) was for the very reasons that Bart brought up.

I wanted to hear some specifics on the pistol barrels that you have worn out...as your conclusions seemed to be drawn from your own personal experience.

Correct me if I have this wrong...

You shared that you wore out a Springfield 1911 barrel in 45acp by shooting 6,000 of Winchester factory 230g FMJ ammo through it?

[LPatterson]

Ari, this is from someone who has been here a little bit longer than you, G-ManBart is after all a G-man and his posts are factual answers with very little opinion and very few digs or at least that is my opinion. There are times and places where my posts get close to or are digs but I am trying to clean up my act.

From back in the beginning of this post you were talking about the problem with moly coating, have you considered the problem might be with the brand of bullet or the roughness of the bore. There will probably be howls and people beating down my door but I would clean the bore with Butch's Bore Shine on a patch followed by some Kroil. I am not talking the 5 minute push the patch through the bore and the patch need to be on a jag properly sized to the bore. Once you get the bore clean of the moly spots, I'd try a different bullet as not all moly is the same, after that keep all metal brushes out of the bore. Solvents fit in two categories, so strong your wife chases you out of the house and say use adequate ventilation and the newer brands that have almost no smell. Personally if it is too strong for my nose I don't want it in my gun because I have used nasty stuff for other cleaning purposes that has now been banned.

I voted for jacketed bullets but I have cleaned my share of wheelweights out of a 357 mag.

[AriM]

The reason I asked you to start a new and specific thread (which...you were a bit off on) was for the very reasons that Bart brought up.

I wanted to hear some specifics on the pistol barrels that you have worn out...as your conclusions seemed to be drawn from your own personal experience.

Correct me if I have this wrong...

You shared that you wore out a Springfield 1911 barrel in 45acp by shooting 6,000 of Winchester factory 230g FMJ ammo through it?

I think what is closer to what I said, is that I noticed an unacceptable decrease in accuracy after only 6000 rounds of WWB through this specific barrel (and also a lack of definition between lands and grooves)....to the point that I felt it necessary to change the barrel....if that is due to other factors (possible deforming of the barrel bottom lugs) I am willing to entertain that notion....I have, however, NOT had the same issue with un-jacketed bullets, after exponentially more rounds through various guns.....

this all stems from our friendly debate on the other thread, that there is NO benefit that I can see, to jacketed bullets in uncompensated guns (making less than 1700fps)

[AriM]

Ari, this is from someone who has been here a little bit longer than you, G-ManBart is after all a G-man and his posts are factual answers with very little opinion and very few digs or at least that is my opinion. There are times and places where my posts get close to or are digs but I am trying to clean up my act.

From back in the beginning of this post you were talking about the problem with moly coating, have you considered the problem might be with the brand of bullet or the roughness of the bore. There will probably be howls and people beating down my door but I would clean the bore with Butch's Bore Shine on a patch followed by some Kroil. I am not talking the 5 minute push the patch through the bore and the patch need to be on a jag properly sized to the bore. Once you get the bore clean of the moly spots, I'd try a different bullet as not all moly is the same, after that keep all metal brushes out of the bore. Solvents fit in two categories, so strong your wife chases you out of the house and say use adequate ventilation and the newer brands that have almost no smell. Personally if it is too strong for my nose I don't want it in my gun because I have used nasty stuff for other cleaning purposes that has now been banned.

I voted for jacketed bullets but I have cleaned my share of wheelweights out of a 357 mag.

Why is this thing about someone being here longer than me a constant statement around here? For all you guys know I could be a ballistics expert in a well funded laboratory, or something similar....who just happened to join the forum out of curiosity....why does it matter at all that Bart is a federal employee? For all we know he could have nothing to do with ballistics. Why does someone being a good shooter, or a professional LE or government worker, somehow make them more qualified than anyone else.....there is no evidence of that....that is a bias...."I'm a gunslinger, so I am better than you"....c'mon we are adults here right?

Like I said no animosity towards anyone, I am an honest and loyal individual, and if people would drop their prejudices they would probably see that I make it very clear, in all my posts, that I am doing nothing more than stating my own opinions....instead, it seems like those who feel they have been here longer want to roast me on a spit, for questioning their superior status on this forum....it's the internet guys, c'mon....seriously....it's really easy to stand on a soapbox and preach from behind your keyboard...which is what I am doing now, so I will stop

this is not aimed (pun?) at the quote above, it's just a general statement.....give a "new" guy a chance before you jump on him like a pack of wolves....

Now back to answering this very excellent post that I have quoted....

I have tried various brands of moly coated bullets....as well as my own cast bullets as well as many jacketed brands as well as etc etc etc....just like most folks here...I like to try new things, and hope they will equal some justified benefit...I am going to have to agree with the logic behind the strong solvent/metal brush combo....it always scared the crap out of me to scrub my barrel with a metal brush, and just listening to the sound of it makes me cringe....but I got used to it, because the majority of people (on another forum) told me I was being paranoid, and that "everyone cleans their barrel with a metal brush"....the same is true with the various solvents...I am well aware of the metal etching potential of even vinegar....so how could ammonia be any better

I think I am going to stop shooting the moly coated bullets....I honestly see no benefit and lot's of trouble....I am just going to go back to shooting my own hard cast projectiles (which worked just fine)....

I still have to say, that for whatever reason, I think jacketed bullets will wear a barrel faster than un jacketed....and that I can see no real problem with un jacketed lead in uncompensated guns (under 1700fps)....which is where this whole topic came from to begin with (please see the thread about "wasting 9mm brass" in this same section)....

[GrumpyOne]

An unjacketed lead projectile traveling at little more than 1,200 fps will start to lead your barrel. Shoot too many, barrel closes up, accuracy goes south, gun goes "boom". Seen it. Yes, jacketed bullets will wear out a barrel faster, but not from the jacket. As G-Man said, it's from flame cutting from the burning powder. Do a search for information on Moly bullets, look for older posts, on Google. Much of what I have read about moly bullets (mostly in rifles though) was that the early moly coating would coat the inside of the barrel's lands and grooves, harden, and with the differences in metals from the bore and the moly, would allow condensation to build up under the moly (if not removed immediately after firing) and cause pitting and erosion of the lands and grooves.

PS. G-Man is one of the most knowledgable persons on here. I have asked him some damn silly questions, and he has never "dissed" me or the dumb question I asked, just answered in a factual manner. In fact, he won a poll to find the most helpful person in the forums....

Methinks you need a thicker skin....

[Alan550]

deleted

Alan~^~

Edited December 18, 2009 by Alan550

[G-ManBart]

I'm pretty sure the comment about me being a federal employee was sort of made in jest...that's the way I'd take it, as I get to work around a bunch of federal employees on a regular basis and well, it's not always impressive

I think we're seeing something here that isn't all that complicated, but isn't completely obvious. I'll try my best to be polite but make it as obvious as I can.

We all know how people sometimes take 2+2 and get 5 right? That's what's happening here. The question asked is "do jacketed bullets wear out barrels faster than lead bullets". Let's break that down to what an end user might experience which would give them an opinion of the event.

Shooter A puts 10K rounds of lead bullets through a gun with little or no loss of accuracy (this equals 2).

Shooter A also puts 10K of jacketed rounds through a similar gun, and the accuracy falls off at some point along the way, such that it's enough to be obvious (this equals 2).

Shooter A says "jacketed bullets wore out the barrel faster than the lead bullets did (this equals 5).

How? Well, when we go back and look, the loads weren't identical, from a wear standpoint. Shooter A didn't shoot 10K worth of rounds, of both types, with the identical powder charge. He shot 10K that had maybe 4gr of powder in his lead bullet load. He shot 10K that had maybe 5gr of powder in his jacketed load. That's a 25% increase in powder and an exponential increase in the flame cutting the barrel experienced, so it wore out faster. The bullet, by itself, didn't cause the wear, the required increase in powder necessary to meet the desired velocity caused the increased wear.

Now, the reason I say there really isn't much debate on the topic stems from the folks that study this on a scientific basis, which isn't exactly what we're seeing in a poll here....as experienced as many of the folks are. Just hold on to that for a minute.

While there is a slight increase in friction going from lead to jacketed, it's not a huge factor. Take a look at something like a high power rifle barrel, where pressures and temperatures are typically much higher than what our pistol barrels are subjected to. In other words, they show the problems sooner, and more dramatically than you'll see with a pistol, but the mechanisms are all the same. What part of a high power barrel wears first, and causes a loss of accuracy? I think everyone will agree that it's the barrel throat....right?

So riddle me this Batman If the throat wears out first, how is it this is the place where the bullet is going it's absolute slowest???? Obviously, it's not the friction of the bullet causing the most wear if it's when the bullet is at it's slowest. If it was the bullet causing the wear, that wear would be at it's worst where the bullet was at it's highest velocity (somewhere beyond 10" from the chamber for typical cartridges....but certainly not at the throat. The hot, expanding gases from the burning gunpowder are at their highest temperature right at the mouth of the cartridge...the barrel throat. That just happens to be the place where the worst wear happens in a barrel! Now we know where the correct answer (4) is found.

High power rifle shooters, and bench rest shooters know about this. They've studied it, and figured it out using fully sorted data. I've even seen an exact formula that will predict how long a barrel will last....it's tied to the bore diameter and the powder charge you use in the case. Turns out, they're right on the money using that formula....or close enough for anybody to see it's got to be factual. They'll tell you things like "don't make a match rifle in .243Win. It'll shoot accurately enough, but they wear out barrels fast". That's because of the bore to case volume/powder charge ratio....more powder through a smaller tube. They'll also talk about other cartridges that wear faster or slower and it's always tied to bore to case volume (really powder charge size, but the two tend to coincide in most situations)....not velocity. A typical .243 match load isn't going much faster, if any, than a typical .308Win match load, but I know (and they know) which is going to wear out the barrel faster....the .243. The bullet material isn't causing the wear, it's causing a change in the load, which causes the wear....okay, with a very small percentage attributed to the friction and bullet sealing differences. R,

[AriM]

I'm pretty sure the comment about me being a federal employee was sort of made in jest...that's the way I'd take it, as I get to work around a bunch of federal employees on a regular basis and well, it's not always impressive

I think we're seeing something here that isn't all that complicated, but isn't completely obvious. I'll try my best to be polite but make it as obvious as I can.

We all know how people sometimes take 2+2 and get 5 right? That's what's happening here. The question asked is "do jacketed bullets wear out barrels faster than lead bullets". Let's break that down to what an end user might experience which would give them an opinion of the event.

Shooter A puts 10K rounds of lead bullets through a gun with little or no loss of accuracy (this equals 2).

Shooter A also puts 10K of jacketed rounds through a similar gun, and the accuracy falls off at some point along the way, such that it's enough to be obvious (this equals 2).

Shooter A says "jacketed bullets wore out the barrel faster than the lead bullets did (this equals 5).

How? Well, when we go back and look, the loads weren't identical, from a wear standpoint. Shooter A didn't shoot 10K worth of rounds, of both types, with the identical powder charge. He shot 10K that had maybe 4gr of powder in his lead bullet load. He shot 10K that had maybe 5gr of powder in his jacketed load. That's a 25% increase in powder and an exponential increase in the flame cutting the barrel experienced, so it wore out faster. The bullet, by itself, didn't cause the wear, the required increase in powder necessary to meet the desired velocity caused the increased wear.

Now, the reason I say there really isn't much debate on the topic stems from the folks that study this on a scientific basis, which isn't exactly what we're seeing in a poll here....as experienced as many of the folks are. Just hold on to that for a minute.

While there is a slight increase in friction going from lead to jacketed, it's not a huge factor. Take a look at something like a high power rifle barrel, where pressures and temperatures are typically much higher than what our pistol barrels are subjected to. In other words, they show the problems sooner, and more dramatically than you'll see with a pistol, but the mechanisms are all the same. What part of a high power barrel wears first, and causes a loss of accuracy? I think everyone will agree that it's the barrel throat....right?

So riddle me this Batman If the throat wears out first, how is it this is the place where the bullet is going it's absolute slowest???? Obviously, it's not the friction of the bullet causing the most wear if it's when the bullet is at it's slowest. If it was the bullet causing the wear, that wear would be at it's worst where the bullet was at it's highest velocity (somewhere beyond 10" from the chamber for typical cartridges....but certainly not at the throat. The hot, expanding gases from the burning gunpowder are at their highest temperature right at the mouth of the cartridge...the barrel throat. That just happens to be the place where the worst wear happens in a barrel! Now we know where the correct answer (4) is found.

High power rifle shooters, and bench rest shooters know about this. They've studied it, and figured it out using fully sorted data. I've even seen an exact formula that will predict how long a barrel will last....it's tied to the bore diameter and the powder charge you use in the case. Turns out, they're right on the money using that formula....or close enough for anybody to see it's got to be factual. They'll tell you things like "don't make a match rifle in .243Win. It'll shoot accurately enough, but they wear out barrels fast". That's because of the bore to case volume/powder charge ratio....more powder through a smaller tube. They'll also talk about other cartridges that wear faster or slower and it's always tied to bore to case volume (really powder charge size, but the two tend to coincide in most situations)....not velocity. A typical .243 match load isn't going much faster, if any, than a typical .308Win match load, but I know (and they know) which is going to wear out the barrel faster....the .243. The bullet material isn't causing the wear, it's causing a change in the load, which causes the wear....okay, with a very small percentage attributed to the friction and bullet sealing differences. R,

It all sounds logical Bart, but it's not a 2+2=5 scenario at all....it's an observation....all science is based on observation (nothing more)....so I am not going to sit here and disagree with your opinion about why jacketed loads wear a barrel faster, that may in fact be true....and I can't verify nor deny it. I just don't have the raw data to make a call in either direction.

But riddle me this Bartman....don't we have to make major PF in pistols that also shoot lead....by my information, not many jacketed factory loads make major PF....so wouldn't observations showing hotter lead loads, leading to longer barrel life, than factory jacketed loads, put a wrinkle in the over all theory you are presenting?

I think an in depth test should be done of this....I wish I had the $$$ laying around to go run the test....shoot identical loads....only variable is jacket vs. no jacket....through identical barrels....under identical conditions....measure the land/groove depth on each barrel after 10k rounds of each type of projectile....

if you know of such a test, and can link me to the results, I would be very much inclined to re-formulate my opinion based on those results....but as it stands....for what ever reason, flame cutting, or otherwise.....jacketed loads wear out a barrel faster right?

if you want to think of that as 2+2=5 then that is your choice.....but it is, as this poll is, nothing more than your opinion...respected and noted....

I do find it interesting though, that rifle cartridges such as the WSSM's have a large powder to projectile ratio....and they aren't reported to have unusually poor wear characteristics...let me dig up some books and do some research on the subject....and I will try to find some quotes that offer arguments for both sides of this debate....

as it stands though, the poll shows that (for whatever reason) the majority of people on this thread believe that jacketed bullets wear barrels faster....

[belus]

While there is a slight increase in friction going from lead to jacketed, it's not a huge factor. Take a look at something like a high power rifle barrel, where pressures and temperatures are typically much higher than what our pistol barrels are subjected to. In other words, they show the problems sooner, and more dramatically than you'll see with a pistol, but the mechanisms are all the same. What part of a high power barrel wears first, and causes a loss of accuracy? I think everyone will agree that it's the barrel throat....right?

So riddle me this Batman If the throat wears out first, how is it this is the place where the bullet is going it's absolute slowest???? Obviously, it's not the friction of the bullet causing the most wear if it's when the bullet is at it's slowest. If it was the bullet causing the wear, that wear would be at it's worst where the bullet was at it's highest velocity (somewhere beyond 10" from the chamber for typical cartridges....but certainly not at the throat. The hot, expanding gases from the burning gunpowder are at their highest temperature right at the mouth of the cartridge...the barrel throat. That just happens to be the place where the worst wear happens in a barrel! Now we know where the correct answer (4) is found.

That's one of the best pedagogical posts I've seen on any forum. Excellent example.

And after a little research I believe GrumpyOne's explanation that early moly coatings enhance corrosion of the bore by attracting water. Apparently the small (micron scale) particles of molybdenum disulfide used as the lubricant are hydrophilic.

Perhaps this is a little off topic, but does anyone know if our "moly coated" pistol bullets are coated in molybdenum disulfide impregnated nylon? This is just speculation, but Nylatron is a commercial self-lubricating plastic of that composition, and nylon coated bullets are not without precedent.

Edited December 18, 2009 by belus

[G-ManBart]

It all sounds logical Bart, but it's not a 2+2=5 scenario at all....it's an observation....all science is based on observation (nothing more)....

Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

But riddle me this Bartman....don't we have to make major PF in pistols that also shoot lead....by my information, not many jacketed factory loads make major PF....so wouldn't observations showing hotter lead loads, leading to longer barrel life, than factory jacketed loads, put a wrinkle in the over all theory you are presenting?

Where are you getting that info? LOTS of factory loads make major in .40, 45, 10mm etc...in fact, most factory ammo for those makes Major.

I think an in depth test should be done of this....I wish I had the $$$ laying around to go run the test....shoot identical loads....only variable is jacket vs. no jacket....through identical barrels....under identical conditions....measure the land/groove depth on each barrel after 10k rounds of each type of projectile....

if you know of such a test, and can link me to the results, I would be very much inclined to re-formulate my opinion based on those results....but as it stands....for what ever reason, flame cutting, or otherwise.....jacketed loads wear out a barrel faster right?

if you want to think of that as 2+2=5 then that is your choice.....but it is, as this poll is, nothing more than your opinion...respected and noted....

I do find it interesting though, that rifle cartridges such as the WSSM's have a large powder to projectile ratio....and they aren't reported to have unusually poor wear characteristics...let me dig up some books and do some research on the subject....and I will try to find some quotes that offer arguments for both sides of this debate....

as it stands though, the poll shows that (for whatever reason) the majority of people on this thread believe that jacketed bullets wear barrels faster....

Here, I'll add some info for your testing prep....might save you some time

None of these folks below seem to think any of this is an opinon. In fact, read the first link and you'll see a reference to a test the Navy did with a match gun using jacketed wadcutter ammo (light loads). The gun didn't lose accuracy through the first 25,000 rounds, but then it fell off by 30K....remember, they were jacketed bullets. Their experience with hardball match guns (full 230gr loads) showed that accuracy fell off after 15,000. Both jacketed bullets, but the hardball were loaded with more powder, to higher pressures, and they wore out sooner. That's a pretty scientific test, not an opinion.

http://yarchive.net/gun/barrel/barrel_life.html

http://www.riflebarrels.com/faq_lilja_rifle_barrels.htm#Life

http://www.exteriorballistics.com/reference/rifleinout.cfm

[AriM]

It all sounds logical Bart, but it's not a 2+2=5 scenario at all....it's an observation....all science is based on observation (nothing more)....

Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

But riddle me this Bartman....don't we have to make major PF in pistols that also shoot lead....by my information, not many jacketed factory loads make major PF....so wouldn't observations showing hotter lead loads, leading to longer barrel life, than factory jacketed loads, put a wrinkle in the over all theory you are presenting?

Where are you getting that info? LOTS of factory loads make major in .40, 45, 10mm etc...in fact, most factory ammo for those makes Major.

I think an in depth test should be done of this....I wish I had the $$$ laying around to go run the test....shoot identical loads....only variable is jacket vs. no jacket....through identical barrels....under identical conditions....measure the land/groove depth on each barrel after 10k rounds of each type of projectile....

if you know of such a test, and can link me to the results, I would be very much inclined to re-formulate my opinion based on those results....but as it stands....for what ever reason, flame cutting, or otherwise.....jacketed loads wear out a barrel faster right?

if you want to think of that as 2+2=5 then that is your choice.....but it is, as this poll is, nothing more than your opinion...respected and noted....

I do find it interesting though, that rifle cartridges such as the WSSM's have a large powder to projectile ratio....and they aren't reported to have unusually poor wear characteristics...let me dig up some books and do some research on the subject....and I will try to find some quotes that offer arguments for both sides of this debate....

as it stands though, the poll shows that (for whatever reason) the majority of people on this thread believe that jacketed bullets wear barrels faster....

Here, I'll add some info for your testing prep....might save you some time

None of these folks below seem to think any of this is an opinon. In fact, read the first link and you'll see a reference to a test the Navy did with a match gun using jacketed wadcutter ammo (light loads). The gun didn't lose accuracy through the first 25,000 rounds, but then it fell off by 30K....remember, they were jacketed bullets. Their experience with hardball match guns (full 230gr loads) showed that accuracy fell off after 15,000. Both jacketed bullets, but the hardball were loaded with more powder, to higher pressures, and they wore out sooner. That's a pretty scientific test, not an opinion.

http://yarchive.net/gun/barrel/barrel_life.html

http://www.riflebarrels.com/faq_lilja_rifle_barrels.htm#Life

http://www.exteriorballistics.com/reference/rifleinout.cfm

science IS simply observation, recorded and compared....for one to believe that they have ALL of the variables figured out, is foolish right? so all we can do within the scientific method is test, observe, evaluate and re-test....there is no hard fact....there is repeatable outcome, but that is still based on conjecture....

wait, on the navy test, how can that be a scientific test? there is no control group.....it is 2 totally different bullets of different weight right? I am not sure that's what I am looking for....

as far as opinion, EVERYTHING is opinion.....the sky is blue.....no the sky has no color what so ever......no you are both wrong the sky is aqua....no all of you guys are full of it, I say the sky is red.....because I said so

do you see my point? just because you reach a repeatable conclusion, it is still only theory...therefore it is the held opinion of a group of people....it is NOT 100%.....you and I both know that....science, by it's fundamental principles, states that one can only invoke theory and back that theory with testing and objective evaluation....

you still haven't told me what your answer on the poll is.....do you believe that shooting jacketed bullets will wear out a barrel faster than shooting un-jacketed?

not heckling you Bart, I truly do respect your opinion.....but I still see no way for anyone to argue or dispute that shooting jacketed bullets will wear a barrel faster (for whatever reason)....the poll says it.....your evaluation says it, my personal experience says it....it's just a poll, with simple choices.....it shouldn't be a debate....yet it is

interested to hear your thoughts....and as long as you respect my right to hold an opinion....I respect yours....this is not about right or wrong for me....this is about opinion and experience....nothing more....a simple selection on the poll doesn't validate or invalidate what either one of us is saying (because at no point have I said that what you are saying isn't correct).....we're on the same page yet?

EDIT : I read the links.....link one, which is an open debate.....seems to have many folks questioning the authors views...

NONE of the links show a scientific testing routine, just opinions of manufacturers and various people

can you please link me to the Navy test you described....I would like to see the scientific method that their test was conducted with...it's already a bit iffy to me, since they tested 2 totally different weights of projectile.....thanks

Edited December 18, 2009 by AriM

[belus]

If anyone wants to see where this debate is going, look here:

http://plato.stanford.edu/entries/scientific-realism/ (specifically the the "Post-modern" Challenge)

Maybe we can save ourselves some time and heartache.

Edited December 18, 2009 by belus

[Flexmoney]

....it's an observation....all science is based on observation (nothing more)....

Your observation is based on a sample size of 1...the single barrel you had issue with And, there may be variables that are unknown.

When you told me that you wore out a barrel in 6k from shooting factory ball...that sparked more questions in my mind than answers.

Around here...that is about where we'd call a gun "broken in".

[AriM]

....it's an observation....all science is based on observation (nothing more)....

Your observation is based on a sample size of 1...the single barrel you had issue with And, there may be variables that are unknown.

When you told me that you wore out a barrel in 6k from shooting factory ball...that sparked more questions in my mind than answers.

Around here...that is about where we'd call a gun "broken in".

partially true....not debating the possible variables....but I understand it to be general held opinion, and my own experience (although it may be limited to the one barrel experience)....I still think that we can conclude from the poll results....and from what Bart is saying....that we are all on the same page right?.....for whatever reason, flame cutting or otherwise, shooting jacketed bullets does decrease the life of a barrel?

maybe something else caused my barrel wearing and losing accuracy prematurely.....I can't really say for sure....only speculate, based on what I understand to be common knowledge and my own observation....that I have yet to have the same issues with shooting un-jacketed bullets....

on a similar note....I had another SA barrel do something VERY odd....if I post a picture will you try to diagnose what happened?

I think SA's 2 piece barrels are kind of on the "weak" side?? Won't buy one again, I have had 2 go south on me.....the one lost all accuracy....the other....well you have to see a picture of this....I'll try to get one up in just a bit....

P.S. also, not to be smug, or try to dispute anyone's opinion.....but look at the poll results....are that many people misinformed?

[GrumpyOne]

quote:Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

That, I don't agree with G-man. I believe Galileo proved several years back that objects of different weights but of similar construction (say, 2 different cannon balls, a 6 pounder and a 12 pounder) dropped at the same time, from the same height, side by side, where the air density is equal, will both hit the earth at the same time. Gravity affects all objects the same.

[s_gorilla45]

quote:Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

That, I don't agree with G-man. I believe Galileo proved several years back that objects of different weights but of similar construction (say, 2 different cannon balls, a 6 pounder and a 12 pounder) dropped at the same time, from the same height, side by side, where the air density is equal, will both hit the earth at the same time. Gravity affects all objects the same.

Thread drift...

Still not quite true Grumpy. In a vacuum the two balls would hit at the same instant. You would have to take air resistance into account even where the air density is equal. If the two cannon balls were the same size but one weighed 12 lbs and the other 6 lbs the heavier ball would be less affected by the air resistance component of the acceleration equation.

[G-ManBart]

quote:Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

That, I don't agree with G-man. I believe Galileo proved several years back that objects of different weights but of similar construction (say, 2 different cannon balls, a 6 pounder and a 12 pounder) dropped at the same time, from the same height, side by side, where the air density is equal, will both hit the earth at the same time. Gravity affects all objects the same.

My point, maybe not clearly stated, was that watching two dissimilar balls of different weights could fool you, just as shooting two dissimilar bullets could fool you. One is a 10" ball and weighs 1lb. The other is a 6" ball that weighs 2lbs. You drop them, the smaller, heavier ball hits first so you say "gee, the heavier ball hit first" when in reality it was the smaller ball with less air resistance hitting first....the weight wasn't the deciding factor, but somebody who didn't really understand the whole system could be tricked into making that assumption....another 2+2=5 situation.

Edited December 20, 2009 by G-ManBart

[GrumpyOne]

quote:Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

That, I don't agree with G-man. I believe Galileo proved several years back that objects of different weights but of similar construction (say, 2 different cannon balls, a 6 pounder and a 12 pounder) dropped at the same time, from the same height, side by side, where the air density is equal, will both hit the earth at the same time. Gravity affects all objects the same.

Thread drift...

Still not quite true Grumpy. In a vacuum the two balls would hit at the same instant. You would have to take air resistance into account even where the air density is equal. If the two cannon balls were the same size but one weighed 12 lbs and the other 6 lbs the heavier ball would be less affected by the air resistance component of the acceleration equation.

First, did I say the two balls were of differing sizes? I said WEIGHT. Second, with the air density being the same, both WOULD hit the ground at the same time, gravity does not pull "harder" on heavier objects. Vacuum (no air density) or regular breathable air, both would still hit at the same time...Maybe if you dropped 6lbs of lead and 12lbs feathers, you might get your result..

Gravity accelerates an object high up in the

air downward at the usual rate of 32 ft/second/second. As it accelerates,

however, the air resistance increases, roughly like speed at low speeds and

then more like the square of the speed. Finally, the air resistance exerts

an upward force exactly equal and opposite to the force of gravity. The

object will then continue to fall at that speed, which is called the

terminal speed.

Exactly what the terminal velocity is depends on the shape, size, and

density of the object. The terminal velocity of a man with an open

parachute is much slower than that of a man without a parachute. It also

depends on the material the object moves through. Terminal velocity of a

steel ball falling through water is much slower than that of a steel ball

falling through air. An object falling in a vacuum has no terminal

velocity. The only limit would be due to Einstein's relativity, a

completely different subject.

Dr. Ken Mellendorf

Physics Instructor

Illinois Central College

Newton's laws....Galileo

[G-ManBart]

P.S. also, not to be smug, or try to dispute anyone's opinion.....but look at the poll results....are that many people misinformed?

Well, from what I've seen you don't really have anything to be smug about, but go ahead if it'll make you feel better

A couple of hundred years ago you could have taken a poll and almost everybody would have said the world was flat.....

I'm putting together a reply of your earlier post. It's another pile of people who actually study this stuff saying what I'm saying

Here's one of the links to a nice article/interview with Boots Obermeyer (it has some references):

http://www.snipersparadise.com/tsmag/june2001.htm

A quick exerpt for those who don't want to read the whole article:

A mistaken view is that loss of barrel life is due solely to the abrasive action of the projectile with the barrel's rifling. This is partially true; however, the main culprit is bore erosion followed by bore wear. Bore wear and bore erosion are not synonymous. Bore wear results from the removal of metal from the bore's surface by mechanical abrasion. Bore erosion results from the removal of metal from the bore's surface by hot propellant gases. Abrasive wear is gradual and usually even to the surface of the bore. On the other hand, erosion can be rapid, particularly when the bore is exposed to continuous high temperatures. Erosion is the major cause of barrel wear with the greatest focus directed toward the area where the rifling begins (Figure 1). The hot metal from the bore's surface reacts with the propellant gases to produce a brittle state that results in metal pieces being removed during subsequent firings. In addition to bore wear and erosion, corrosion should be considered as a contributing factor even though it plays a minor role with non-corrosive propellants and primers.

[s_gorilla45]

quote:Science isn't simply observation, it's observation combined with understanding the factors that are in play and how they interact. You can watch two items fall the same distance and the heavier one hits first. That doesn't mean that weight caused it to accelerate more, but that might be what someone who doesn't understand all the factors would conclude....which is what's going on in your theory. Knowing the outcome doesn't mean you know what caused it if you don't remove all of the differences (like powder charge, in our situation).

That, I don't agree with G-man. I believe Galileo proved several years back that objects of different weights but of similar construction (say, 2 different cannon balls, a 6 pounder and a 12 pounder) dropped at the same time, from the same height, side by side, where the air density is equal, will both hit the earth at the same time. Gravity affects all objects the same.

Thread drift...

Still not quite true Grumpy. In a vacuum the two balls would hit at the same instant. You would have to take air resistance into account even where the air density is equal. If the two cannon balls were the same size but one weighed 12 lbs and the other 6 lbs the heavier ball would be less affected by the air resistance component of the acceleration equation.

First, did I say the two balls were of differing sizes? I said WEIGHT. Second, with the air density being the same, both WOULD hit the ground at the same time, gravity does not pull "harder" on heavier objects. Vacuum (no air density) or regular breathable air, both would still hit at the same time...Maybe if you dropped 6lbs of lead and 12lbs feathers, you might get your result..

Gravity accelerates an object high up in the

air downward at the usual rate of 32 ft/second/second. As it accelerates,

however, the air resistance increases, roughly like speed at low speeds and

then more like the square of the speed. Finally, the air resistance exerts

an upward force exactly equal and opposite to the force of gravity. The

object will then continue to fall at that speed, which is called the

terminal speed.

Exactly what the terminal velocity is depends on the shape, size, and

density of the object. The terminal velocity of a man with an open

parachute is much slower than that of a man without a parachute. It also

depends on the material the object moves through. Terminal velocity of a

steel ball falling through water is much slower than that of a steel ball

falling through air. An object falling in a vacuum has no terminal

velocity. The only limit would be due to Einstein's relativity, a

completely different subject.

Dr. Ken Mellendorf

Physics Instructor

Illinois Central College

Newton's laws....Galileo

We're agreeing with each other Grumpy...

[GrumpyOne]

We're agreeing with each other Grumpy...

Yeah, and I still think and believe that it's hot propellent gases!

A little experiment: Someone take a piece of just plain old steel and get a piece of copper, and rub the copper against the steel as fast and as hard as they can for around 30,000 times, and let's see which erodes first.

[AriM]

so either way shooting jacketed bullets still wears your barrel faster right?

Edited December 20, 2009 by AriM

[jasmap]

I've been on here a few years and I can NOT EVER remember anyone acting as though they felt that way about Bart. He is being direct in his response......NOT rude or condescending.

Edited December 20, 2009 by jasmap

[AriM]

I've been on here a few years and I can NOT EVER remember anyone acting as though they felt that way about Bart. He is being direct in his response......NOT rude or condescending.

"Well, from what I've seen you don't really have anything to be smug about, but go ahead if it'll make you feel better "

if that's not condescending, i don't know what is.........meh.....this is just not worth anyone's time anymore.....it's a poll....I am going to let the poll speak for itself.....no more comments from me in this thread, you guys can argue about it all you want though....I am going to sit on the sidelines with some popcorn and watch....

as I have stated over a dozen times already....shooting jacketed bullets (for whatever reason) wears a barrel faster, just like the poll says....this is just a fruitless debate, the outcome is still the same....flame cutting, friction wear, erosion....whatever the case may be...

Edited December 20, 2009 by AriM

[kgunz11]

Bart, as usual, you're spot on, except in this aspect:

A typical .243 match load isn't going much faster, if any, than a typical .308Win match load

The .243 is and will always be faster than the .308. Same parent case, much lighter weight projectile. Typical .308 match load puts a 175gr SMK at around 2650 for most folks. The .243 match load runs a 115gr DTAC bullet in the realm of 3050 for most. That's a pretty substantial difference IMO (most competitive folks shoot both rounds about 100fps faster that posted).

Let me share a few FACTS which are more than "observations".

Moly = less friction thus less pressure, so you must up the powder charge to achieve the targets velocity range

Less friction = less bbl wear

More powder = more barrel wear

Initially, moly was thought to slicken a bbl to the point that bbl life would be enhanced. Scientific research shows that heat is the main factor in barrel degradation. More powder to get moly coated bullets at a desired velocity range nullified the benefit of the less friction and caused barrel to wear equally.

Moly traps moisture and condensation under its layer which causes the bbl to rust. If left in too long, this can cause irreparable damage to the bore.

While the new guy in all his infinite wisdom might have made a few observations, I wonder if he used a pressure trace or measured temps to compare the difference in powder burn rate/residual powder temperature. Best I can tell, he is comparing Win White Box to a hand load he rolled himself. If a different powder was used between the 2 loads, there is nothing scientific about his observations at all.

The #1 factor to bbl degradation is heat.

The heat produced by the powder is greater than the friction reduced by using Moly.

Absolutely everything in my post is a fact. Well, except for maybe the "infinite wisdom" part. Bart, I have a barrel wear chart based on common propellants and the aspect ratio to bore diameter on my computer somewhere, I need to dig it up for you.