Is there such thing as plateauing?

[robot]

Just went out to chrono some rounds I made up through a Chrony today. My ammo recipe is

• Montana Gold 115 & 124 CMJ
  
• Vihtavouri N105
  
• Starline Brass (mostly) brand new
  
• Winchester Small Rifle Primer
  
• 1.240" OAL
  

Loaded this on a Dillon 550b. Shooting out of a 5" Schuemann Ultimatch 38 Super barrel.

This table is for MG 125gr CMJ:

    9.8gr  9.9gr 10.0gr 10.1gr 10.2gr 
1  1379.0 1391.0 1384.0 1358.0 1413.0 
2  1397.0 1418.0 1388.0 1413.0 1402.0 
3  1400.0 1404.0 1401.0 1408.0 1418.0 
4  1346.0 1402.0 1381.0 1383.0 1388.0 
5  1413.0 1390.0 1407.0 1396.0 1394.0 
6  1411.0 1394.0 1424.0 1396.0 1418.0 

Av 1391.0 1399.8 1397.5 1392.3 1405.5 
PF  172.5  173.6  173.3  172.6  174.3 
SD   25.1   10.5   16.4   19.8   12.8 

What's bizarre to me is increase in Powder has no affect on velocity!

Same thing for MG 115gr CMJ :

   10.2gr 10.4gr 10.5gr 10.6gr   
1  1430.0 1440.0 1410.0 1451.0   
2  1466.0 1469.0 1443.0 1439.0   
3  1430.0 1452.0 1457.0 1442.0   
4  1415.0 1455.0 1436.0     
5  1414.0 1423.0 1450.0 1415.0   
6  1417.0 1452.0 1463.0 1458.0   

Av 1428.7 1448.5 1443.2 1441.0   
PF  164.3  166.6  166.0  165.7   
SD   19.6   15.5   18.8   16.3   

More powder for 115gr and I get LESS velocity! I also have a bunch of pictures of the fired primers at my blog post : http://gunbot.wordpress.com/2011/05/19/38-super-comp-chrono-results/

Can anyone tell me what's wrong?

Edited May 19, 2011 by robot

[Magnus_no1]

VV N105 is not made for that caliber. that's basically why. It is used (but not made for) to optimize the effectiveness of compensators in 38s. The more powder you fill the larger the muzzle flash will be. that's it. The powder is to slow and the barrel to short. N105 is a rifle powder. All VV powders starting whit 1 are made for rifles.

Use 3N38 or N350. And my personal favorite 3N37. Then you would also get rid of the powder spilling in shellplate issue you probably have.

Edited May 19, 2011 by Magnus_no1

[RH45]

Although a lot of guys I know use 105 for .38 super/supercomp, I only tried it once, with 10 grains, behind a Zero, 125 grain jhp, and it was the same pf that I was running with 350, but, I didn't notice enough difference in recoil, or, dot tracking to switch to it, especially being that loading 105 is a PITA, because it fills the case.

[G-ManBart]

How many rounds did you fire for each string....only six? If so, you need to double or triple that, then check the average. When you're talking .1gr of change in powder measure setting, you're often not getting that amount of difference in any individual round (powder measures just can't be that precise). Add in the normal variation you get even when everything is absolutely identical, and it muddies the waters. Throw in that you said you mostly used new brass and you have yet another variable. Lastly, when you're talking 10+gr of powder .1gr is a very small percentage of the overall weight, so the change should be minimal even when all factors are constant.

Do a simple test. Run two strings of 20 rounds at maybe 10.0 and 10.2, and see what happens. I know I've always been able to see a clear change when I do that...no question at all. It's also why I settled on two 20rd strings as my standard baseline when making any changes. R,

[CocoBolo]

One thing that I do is I use a Beam Scale to verify my Electronic Scale readings. Have you ever put a charge on an electronic scale it comes up 10 then a few seconds later you look and it is a 10.1. Kind of kills your confidence in the electronic, I've seen this on several and it is disturbing. I ran into a bit of bad foo in cold weather using an electronic when it got off several tenths, so I keep the dillon beam handy and use it as the final check. The net effect I went to a major match and won the crono stage 189pf.

Electronic scales are only accurate to +-.1, could be in one case it was over and the next it was under.

OAL variance or set back?

You need to figure out that ejection issue before you head off to a match.

Edited May 19, 2011 by CocoBolo

[soaringf22]

i generally increase by .2 but when i was making up a load with AA7 (thanks Ron) if i loaded up with .2 it would have taken me years. like 105 it increases so minimally so i would load +.5 for the first couple then +.2 as it got hotter i started at 7.5gr and my super barrel was so tired it didnt make major till about 12.3gr.

i also build up loads on my single stage press, i get single digit SD and ES. when i load on a dillon these numbers go up to the 30s and 40s. with a fine powder like 105 or AA7 they wouldnt meter consistantly on the dillon the powder would get cuaght in the charge bar and then jam the dillon. maybe i could have tried a large bar? but when i got to major the load was not different enough to care from other loads i have worked up that werent as dirty or hard to work the dillon.

G-man mentioned somewhere else that with the electronic scale weigh 10 different times and average that number. 10.0, 10.1, 9.9, 10.1 will still be about 10.0. this was pretty good advice i guess he was getting the same variance in reading i was getting.

[gng4life]

To answer your original question, yes, there is such a thing as a plateau (it's really an apex since it drops off at a point, a plateau is really where there is no increase or decline) with reloading powders. However, I would advise you to reevaluate your load as G-man recommended. Not enough data to really be conclusive at this point...

[XRe]

First things first - you can increase the accuracy of your scale by weighing more charges at one time and averaging the result (got that from benos) - http://re-gun.com/20...-more-accurate/ - that also tends to average out the error in the powder measure and gives you a very solid idea of the charge you're getting.

Also, get a set of check weights. Using another scale to verify a scale is like the blind leading the blind (and, your balance beam is only accurate to +/- .1gr, too, unless you do the above - but the above applies equally to any scale)

Now... check your OAL. You're loading a very compressed load (I load 11.2 of N105 under a 121) and it's quite possible the bullet is actually not getting seated deep enough. I load to 1.235" OAL - if I seat a bullet on my press without powder in the case, I get something like a 1.150. I have to push deeper/harder on the bullet to get it to stay at 1.235". I suspect this might be your issue - you're adding powder, but if it's pushing the bullet further out, your starting volume is also increasing, which can cause things to not burn as completely or at least negate the effects of adding more powder.

Realize that you're talking about a 1% change in powder charge - the margins of error in your scale, press, and chrono (yes, your chrono has potentially a 3-5% error rate, depending) will eat that entirely. I completely agree with G-Man - after you check OAL, make slightly larger moves in charge (.2gr should be sufficient) and run 10 in a string.

Edited May 19, 2011 by XRe

[Magnus_no1]

I don't agree . There is defiantly enough data to confirm that N105 has nothing more to give in this setup (Please take a look at the 115gr data and think about it a bit longer). If some ones life depended on it I would test some more. If not I would be satisfied and move on.

[Foxbat]

What's bizarre to me is increase in Powder has no affect on velocity!

More powder for 115gr and I get LESS velocity!

Can anyone tell me what's wrong?

What is wrong is the bullet/gun/powder combination. I have seen similar effect, with different powder. I can only surmise the powder burning characteristics require optimal pressure, which you don't get with that bullet, so you are simply pushing the powder and bullet out before it can produce the optimal pressure curve.

[XRe]

I don't agree . There is defiantly enough data to confirm that N105 has nothing more to give in this setup (Please take a look at the 115gr data and think about it a bit longer). If some ones life depended on it I would test some more. If not I would be satisfied and move on.

I know several folks making that load work, and (as I stated in my previous post), there are other issues to look at when loading such a slow powder in such a compressed load. If it wasn't N105, I'd tend to agree, but you obviously do not have experience with this load combination...

[robot]

Thanks for the analysis & advice guys. I'm having the ejection problems fixed now by my gunsmith, JPL (http://jplprecision.com). You should have heard his comment when he took the extractor out and saw it the first time

as for the loads, I'm going to stick with 124gr 10.0gr N105, that seems to be working well and not have any problems with pressure. that'll also not fill up the case with that much powder and avoid compressing the load.

I'll also work on making some 10.8 and 11gr 115CMJ loads just to see if there are any pressure signs and what the velocity is. I guess if I'm using anything less than 124, it'll be a somewhat compressed load like Dave Re mentioned above.

time to go shoot it some more

oh and here's some video I took of it in action :

[Magnus_no1]

I don't agree . There is defiantly enough data to confirm that N105 has nothing more to give in this setup (Please take a look at the 115gr data and think about it a bit longer). If some ones life depended on it I would test some more. If not I would be satisfied and move on.

I know several folks making that load work, and (as I stated in my previous post), there are other issues to look at when loading such a slow powder in such a compressed load. If it wasn't N105, I'd tend to agree, but you obviously do not have experience with this load combination...

I think we both are right in the technical part of it. And you probably have more experience the me in this particular load. But I would never use a load showing that kind of symptoms. I just don't understand why, when you can use a powder made for such a load. That's what I basically mean.

[XRe]

I think we both are right in the technical part of it. And you probably have more experience the me in this particular load. But I would never use a load showing that kind of symptoms. I just don't understand why, when you can use a powder made for such a load. That's what I basically mean.

In other circumstances, I'd agree with you - if the velocities yield by the load start plateauing, or lowering, it's usually considered to be a sign of high pressures. In the case we're dealing with here, it's another issue caused by the compressed nature of the load, not a pressure problem. You could literally dip a supercomp or super case into N105, wipe the powder off level with the top, and cram a bullet down onto it, and you're not going to have pressure problems. The stuff is super safe (no pun intended).

If you can hold OAL consistent, the only issue then becomes if you can fit enough powder behind the bullet. He has enough barrel (though he doesn't mention ports, I have a shorter barrel with ports, and can make Major with that combination) - unless the barrel's somewhat shot out, or is an extremely slow barrel, he shouldn't have a problem getting there. The load he's trying to run is a lower pressure load than a number of the Major 9 loads you see discussed, and a good number of the Super/Supercomp loads with faster powders.

The OP hasn't commented on what his OAL was doing with those loads. When I loaded 121s and 115s with N105 and with 3N38, I started noticing the OAL creep longer, and had to start seating the bullets deeper than my usual setting to keep an upward trend in performance. I've got notes that show the same effect he's seeing - linearity returned when I returned to only have one variable changing in the equation....

There's a lot of reasons to want to use N105 vs. a faster alternative, not the least of which is longevity of the gun due to lower peak pressures in the loads. A powder "made for such a load" is non-existent

That said, I find that my gun likes 121s a lot more than 115s - it's more controllable, smoother to shoot, and a little less blasty... and, surprisingly, seemingly just as flat...

[robot]

Dave,

The OAL i went for was 1.240" and I measured each round after crimping. That said, I have heard that after a while, rounds might creep longer because of the compressed load behind it. Not sure if that's happening or not as I didn't check OAL before I fired them.

My gun does not have any popple holes, just a 3 ports up top that are slightly forward facing, and two ports at the sides.

What OAL are you running in your gun with 121s? Can you share your N105 loads please?

thanks so much

Loke

[XRe]

I've been running Zero 121gr, 11.2gr N105, WSR, 1.235" OAL, .378" crimp, Supercomp brass

I should add, that's with a 4.25" barrel and four poppleholes, so I'm probably losing something like 60 fps vs. your setup... thus the seemingly much higher powder charge.

Check your crimp - make sure you've got enough. These rounds need a bit more than just "take the bell off"...

Edited May 19, 2011 by XRe

[Avezorak]

Cool video. I was ducking to keep from getting hit by brass. Lol

Edited May 19, 2011 by Avezorak

[CocoBolo]

Wow the gun must be a Dolphin its jumping like flipper! Hey, that XRE is the smartest guy I know when it comes to open guns and he is mr methodical in everything. We have disagreed on occasion, but politely. If you watch the video you can see that the flip is coming at the end of the stroke, if you want to cut that down try a heavier recoil spring 10# is what I like, although I have one gun that I run a 9# in. You will get more flip before it hits the end of the storke but the slide will be going slower so it might just help you track the dot.

I'm curious, which power factor in 124gr did you think felt best? I'm betting the 175 pf load felt softer and flatter.

I shoot MTG's but if you measure a Zero and an MTG the MTG is .0005 smaller in diameter, have you measured the diameter of your bullets?

[G-ManBart]

VV N105 is not made for that caliber. that's basically why. It is used (but not made for) to optimize the effectiveness of compensators in 38s. The more powder you fill the larger the muzzle flash will be. that's it. The powder is to slow and the barrel to short. N105 is a rifle powder. All VV powders starting whit 1 are made for rifles.

Use 3N38 or N350. And my personal favorite 3N37. Then you would also get rid of the powder spilling in shellplate issue you probably have.

Untrue. VV's guide lists N105 in their Handgun Powders section, and describes N105 as: "Super Magnum: Slow burning handgun powder filling the gap between N350 and N110. Especially developed for handgun cartridges with heavy bullets and/or large case volume. Reloading data is currently available for the following cartridges: 9x21mm, .38 Super Auto, .357 Mag, .357 Rem Maximum, 40S&W, 10MM Auto, .41 Remington Mag, .44 Remington Mag, .45 Colt, .45 Win Mag and .454 Casull."

N350 and 3N37 are decent powders, but in all of my Open guns, N105 is far superior. 3N38 is in between, but creates huge fireballs at random intervals, and isn't as flat. I've also shot my loads (10.8gr of N105 with a 115gr MG JHP at 1.235") in probably ten+ other Open guns in the last two years, and it's worked very nicely in all of them.

I have yet to see a situation where I added more N105 and I didn't get more velocity (talking an average here). I've probably chrono'd N105 loads somewhere between 50 and 100 times in the last few years (yes, I chrono a lot), and it has yet to do anything unexpected. My minimum is two 20rd strings, so I've got thousands of rounds over the chrono with N105....short guns, 5" guns, guns with popple holes, you name it.

[Magnus_no1]

VV N105 is not made for that caliber. that's basically why. It is used (but not made for) to optimize the effectiveness of compensators in 38s. The more powder you fill the larger the muzzle flash will be. that's it. The powder is to slow and the barrel to short. N105 is a rifle powder. All VV powders starting whit 1 are made for rifles.

Use 3N38 or N350. And my personal favorite 3N37. Then you would also get rid of the powder spilling in shellplate issue you probably have.

Untrue. VV's guide lists N105 in their Handgun Powders section, and describes N105 as: "Super Magnum: Slow burning handgun powder filling the gap between N350 and N110. Especially developed for handgun cartridges with heavy bullets and/or large case volume. Reloading data is currently available for the following cartridges: 9x21mm, .38 Super Auto, .357 Mag, .357 Rem Maximum, 40S&W, 10MM Auto, .41 Remington Mag, .44 Remington Mag, .45 Colt, .45 Win Mag and .454 Casull."

I daubt VV would recommend anyone to fill a case and push down the bullet in the powder and tell the customer. You have to crimp the bullet hard to get it to stay there. Otherwise it will pop out. I don't live that far from where they make it. So I could ask

Sometimes its better to just realize that people have a different opinions.

But I am not in any way saying N105 don't work perfect for many probably successful shooters.

Maybe you just appreciate different things. I like to keep it simple and just shoot instead of pushing it to the limit where you probably ends up with other problems related to that. Spilling powder, bullet popping out, bullets that don't go faster when you put more powder in. And use that time to maybe exercice my hands. Take a look at the movie above. Do you notice anything particular? I do. Maybe N110 would fix it

[G-ManBart]

VV N105 is not made for that caliber. that's basically why. It is used (but not made for) to optimize the effectiveness of compensators in 38s. The more powder you fill the larger the muzzle flash will be. that's it. The powder is to slow and the barrel to short. N105 is a rifle powder. All VV powders starting whit 1 are made for rifles.

Use 3N38 or N350. And my personal favorite 3N37. Then you would also get rid of the powder spilling in shellplate issue you probably have.

Untrue. VV's guide lists N105 in their Handgun Powders section, and describes N105 as: "Super Magnum: Slow burning handgun powder filling the gap between N350 and N110. Especially developed for handgun cartridges with heavy bullets and/or large case volume. Reloading data is currently available for the following cartridges: 9x21mm, .38 Super Auto, .357 Mag, .357 Rem Maximum, 40S&W, 10MM Auto, .41 Remington Mag, .44 Remington Mag, .45 Colt, .45 Win Mag and .454 Casull."

I daubt VV would recommend anyone to fill a case and push down the bullet in the powder and tell the customer. You have to crimp the bullet hard to get it to stay there. Otherwise it will pop out. I don't live that far from where they make it. So I could ask

Sometimes its better to just realize that people have a different opinions.

But I am not in any way saying N105 don't work perfect for many probably successful shooters.

Maybe you just appreciate different things. I like to keep it simple and just shoot instead of pushing it to the limit where you probably ends up with other problems related to that. Spilling powder, bullet popping out (I've never had that problem), bullets that don't go faster when you put more powder in (never had that problem either). And use that time to maybe exercice my hands. Take a look at the movie above. Do you notice anything particular? I do. Maybe N110 would fix it

You may want to spend some time looking at VV's reloading manual. They list a load for .38 Super with a 124gr FMJ and 11.0gr of N105. That's absolutely going to be a compressed load. If they thought it was a problem, they wouldn't publish it.

I use 10.8gr in a .38SC case (which has a couple of tenths less capacity than Super), so I'm running roughly the same amount of compression and guess what? I don't have to use a heavy crimp, and a heavy crimp is NOT what keeps the bullet in place (proper resizing is what does that). When I pull one of my bullets it has a very slight mark where the case mouth was, so it's far from a heavy crimp (.378" or so).

The funny thing here is that I've loaded and shot tens of thousands of rounds of .38SC with N105 in the last couple of years and NONE of these "problems have cropped up! Okay, okay, it is possible to spill powder with some presses, but it hasn't been an issue for me on two different Dillons. I've got a whole bunch of friends who also run N105 (many after trying mine), and none of them report those problems either.

I'm not going to comment on the video because I don't know, for certain, that it was done under the same circumstances as when he would be shooting in a match (in other words, not in front of the camera). I can cut more muzzle flip with a change in grip that with a change in loads, but not everybody believes that, or wants to do the required work to make that a reality.

In many ways, Major loads with N105 in Super/SC are the farthest thing from "pushing the limit" that you can get....it's almost certainly the safest combination out there of all the 9 bores.

[Walküre]

N350 and 3N37 are decent powders, but in all of my Open guns, N105 is far superior. 3N38 is in between, but creates huge fireballs at random intervals, and isn't as flat. I've also shot my loads (10.8gr of N105 with a 115gr MG JHP at 1.235") in probably ten+ other Open guns in the last two years, and it's worked very nicely in all of them.

Interesting how different people have such different experiences... in working up loads for my open gun, I found 3N38 to behave better than N105. N105 was beautifully flat when loaded very near the 165PF mark, but as I pushed it up higher, it seemed to get a bit flippier - while at the same time 3N38 seemed to get flatter. But I'm loading 124gr - perhaps with the lighter bullet, I could find N105 to be better.

Oh, I definitely always saw an increase in velocity with an increase in charge weight. I did not encounter any odd behavior like that reported in the OP.

[XRe]

I don't have to use a heavy crimp, and a heavy crimp is NOT what keeps the bullet in place (proper resizing is what does that). When I pull one of my bullets it has a very slight mark where the case mouth was, so it's far from a heavy crimp (.378" or so).

I agree with G-Man 18,000%. The only thing I'll comment on is this - crimp doesn't do anything to prevent bullet setback, but it does have a hand in preventing the opposite effect (that is, resisting a compressed powder charge from pushing the bullet back out). Proper resizing is also involved, for sure, and also plays a role. Realize that a crimp that leaves a mark in the bullet is heavier than the commonly recommended "just take the bell out of the case" level of crimp, but not necessarily what you'd call a "heavy crimp" (certainly not relative to roll crimp on a magnum class handgun cartridge).

In many ways, Major loads with N105 in Super/SC are the farthest thing from "pushing the limit" that you can get....it's almost certainly the safest combination out there of all the 9 bores.

Bingo. Not to mention as compared to the common .40 loadings using heavy bullets and fast powders...

[XRe]

Interesting how different people have such different experiences...

Interestingly, there may be a biological reason for this, too - I have some theories, but nothing I can prove. It's on my list of stuff to write up in a blog post at some point

in working up loads for my open gun, I found 3N38 to behave better than N105. N105 was beautifully flat when loaded very near the 165PF mark, but as I pushed it up higher, it seemed to get a bit flippier - while at the same time 3N38 seemed to get flatter. But I'm loading 124gr - perhaps with the lighter bullet, I could find N105 to be better.

It's somewhat gun dependent (comp, port config, etc), somewhat shooter dependent (subjective interpretation of inputs). This is why I encourage folks to not evaluate a load or setup based on how it "feels" or seems to move... Instead, base it on scores of drills, etc The timer and targets don't lie... More on that at some point!

[G-ManBart]

Dave's comment on the crimp issue is right on the money (as usual)...I should have been more specific.

Just for giggles, I ran some numbers for .38SC loads on QuickLoad, and I'm betting most folks will be surprised how close they come to my measured results.

My current load is a 115gr MG JHP at 1.235" with 10.8gr of N105. I've only chrono'd it 7 times since making a slight bump from 10.7gr. Six of those were my chrono, one was a major match, and it was a total of 123rds. The average velocity was 1508fps. The temperature varied from 50*F to 85*F. QuickLoad has everything except the MG bullet, so I use the data for a Hornady 115gr XTP, which is extremely close in length and bearing surface. I adjusted the length of the bullet in the program to exactly match the MG bullet (they were off by only .004"). I set the barrel length at 5" to match my gun, and QL popped out an average of exactly 1500fps. QL showed the maximum pressure as 35,140psi, which is under the pressure limit they've assigned it (based off Super most likely), of 36,259psi.

For even more laughs, I plugged in the numbers for a 9 Major load I worked up using the same 115gr MG JHP, and HS-6. I'm not giving the charge out (OAL was 1.170"). My measured results over the chrono averaged out at 1,494fps. QuickLoad gives me 1,497fps.....pretty amazing. Some of this is why I always recommend a couple of 20-shot strings, it's just enough to get a true average, without being overly difficult or time consuming. I'm guessing folks will be interested in what the pressure figures were from QL. Hold on....49,371psi is what it kicks out!

For a final couple of chuckles, and to support what Dave mentioned, I punched in the data for one of my 9 Minor loads; 147gr MG CMJ at 1.125" with 3.7gr of VV N320. I worked up this load with once and twice-fired brass rather than new, which typically costs something like 20-30fps (based off previous testing). My average was at 950fps. QL shows 1010fps. I could have a slow barrel, the lot of powder could be a bit slow, or it could be the used cases, or a bit of all of those things, but still 60fps isn't a huge gap from reality to a program. So, what does QL show the pressure at? 37,207psi That's right, a 9 Minor load (139PF) pushing more pressure than a .38SC Major load (173PF)!

Edited May 21, 2011 by G-ManBart