158 gr RN, which one for ICORE?

[ysrracer]

I like Bayou Bullets 160 grain round nose. They load easily in my Dillon, and put holes in paper.

[Fishbreath]

13 hours ago, Johnny_Chimpo said:

As soft as the bullets we shoot are, I estimate that fragmentation is minimal and energy and momentum transfer is near perfect assuming a head on collision. 

I don't think this is a good assumption at all, though. There's an easy experiment you can do (one that most match directors have done inadvertently). Set up a paper target two or three feet to the side of a popper, angled toward it, and shoot at the popper head on.

 

A paper target so positioned gets torn up fast, suggesting quite a lot of fragmentation happening.

[gargoil66]

8 hours ago, varminter22 said:

Interesting. 

 

So how do you explain the fact that heavier bullets (such as a 230 gr .45ACP @ 750 fps) knock a bowling pin farther than a lighter but faster 9mm/.38 bullet?  

VM:

 

The faster they go, the faster they slow down.  

 

Simply put, the wider and slower .45 bullet transfers its energy over a wider area for a longer period of time.  So, it doesn't use as much energy for the plate or bowling pin to overcome its inertia and move it far enough to make a plate fall or push the bowling pin off the table.  

 

I think the .45 bullet would also retain more of its mass when it strikes and some of it fragments.

 

Bowling pins are pretty problematic due to their curved shape and hard covering so the bullet is probably never hitting it at anything near zero obliquity so size and ogive probably play a much bigger role than on a steel plate where the obliquity is more direct.

 

So, mathematically it is true that both can have the same amount of energy on impact but how that energy is transferred is what makes the difference.

 

GG

 

 

 

 

 

[twodownzero]

19 hours ago, Johnny_Chimpo said:

I rely on physics not anecdotal observations

 

It seems that you are confusing a theoretical understanding and an empirical one.

 

That heavier bullets at the same power factor knock steel down better is common knowledge.  As to explaining why, I'll leave that to you.  But that heavier bullets knock steel down more reliably is a fact.  Whether it's energy transfer, the rate of energy transfer, or something else, I don't know.  But some equation that tells you how much energy a bullet has when it hits a plate obviously does not answer the question, because what you call "anecdotal observations" is no such thing with the level of experience we're talking about here.  I ran 300 shooters through the same stage in a 3 day period once.  That isn't anecdotes; it's data.

[pskys2]

1 hour ago, twodownzero said:

 

It seems that you are confusing a theoretical understanding and an empirical one.

 

That heavier bullets at the same power factor knock steel down better is common knowledge.  As to explaining why, I'll leave that to you.  But that heavier bullets knock steel down more reliably is a fact.  Whether it's energy transfer, the rate of energy transfer, or something else, I don't know.  But some equation that tells you how much energy a bullet has when it hits a plate obviously does not answer the question, because what you call "anecdotal observations" is no such thing with the level of experience we're talking about here.  I ran 300 shooters through the same stage in a 3 day period once.  That isn't anecdotes; it's data.

Simple it's called Dwell time, more mass, more momentum & Dwell time.

[varminter22]

2 hours ago, twodownzero said:

 

It seems that you are confusing a theoretical understanding and an empirical one.

 

That heavier bullets at the same power factor knock steel down better is common knowledge.  As to explaining why, I'll leave that to you.  But that heavier bullets knock steel down more reliably is a fact.  Whether it's energy transfer, the rate of energy transfer, or something else, I don't know.  But some equation that tells you how much energy a bullet has when it hits a plate obviously does not answer the question, because what you call "anecdotal observations" is no such thing with the level of experience we're talking about here.  I ran 300 shooters through the same stage in a 3 day period once.  That isn't anecdotes; it's data.

 

21 hours ago, Toolguy said:

I thought that science was about observing what happens, then figuring out why it happens. Silly me. I will stick with my "anecdotal observations" that have stood the test of time. Explaining why something works the way it does is secondary to winning the match.

 

Very well said.  

[twodownzero]

5 hours ago, pskys2 said:

Simple it's called Dwell time, more mass, more momentum & Dwell time.

I don't think it's that simple, because as he's done the math above, the faster/lighter bullets have more energy no matter how you calculate it.

 

I can't explain it to you, but I can show it to you.

[GMM50]

We load our bullets into match ammo for SASS matches.  For 38 special, we load 100g and 158g. 

The surprising part is we use the same amount of powder for each, and each load makes the same power factor. 

It's SASS match ammo and the pf is much lower that USPSA or ICORE. 

Both loads feel fell the same in recoil.  When shooting but you can tell which is the heavier bullet.  Both knock down steel with the same action.

You do have more confidence with the heavier bullet.  And I believe more room for off center hits.

[MHicks]

1 hour ago, GMM50 said:

We load our bullets into match ammo for SASS matches.  For 38 special, we load 100g and 158g. 

The surprising part is we use the same amount of powder for each, and each load makes the same power factor. 

It's SASS match ammo and the pf is much lower that USPSA or ICORE. 

Both loads feel fell the same in recoil.  When shooting but you can tell which is the heavier bullet.  Both knock down steel with the same action.

You do have more confidence with the heavier bullet.  And I believe more room for off center hits.

 

As an example a 100gr bullet at 800fps is 80pf. 158gr would be about 506fps to get 80pf. Is this in the ballpark of what you're describing?

[GMM50]

Yes.  What was interesting to me same pf with same amount of powder.  Could be a fluke of 38 Special cases or low pf for SASS.

[ysrracer]

I tested 160 gr round nose Bayou, Hoosier, Bang & Clang, and Black Bullets International (bbi) in a head to head test.

 

Some had lube groves, some didn't.

 

I posted it here a while back. In the end they all grouped exactly the same at 25 yards. No difference what so ever.

[testosterone]

On 5/17/2022 at 2:24 PM, DukeSoprano said:

I see Berrys has what I think I am looking for and Blue Bullets has a 160?

 

I already have a taper crimp die

 

Thanks

using data from those who came before, berrys 158's in a 38 special, 4.0 tg 1.500 COAL is a very accurate load.   I tried a bunch of other bullets and nothing was a reliably accurate in any case as a berrys bullet aside from jacketed bullets which i disqualified on cost.   The gun also stays much cleaner shooting the plated bullets in my experience, this may or may not matter to you... just my experience, i ended up switching to bayous at some point though when berrys price changed and made them parity with jacketed bullets.   Im not accurate enough in real time for the difference to matter so...

and at this point components have gotten so expensive it hardly matters trying to save some money, i realize in retrospect i had a lot of stupid thought process around all this(budget) that really amounted to a hill of beans.

[GoPewPew]

On 5/18/2022 at 10:34 PM, varminter22 said:

Interesting. 

 

So how do you explain the fact that heavier bullets (such as a 230 gr .45ACP @ 750 fps) knock a bowling pin farther than a lighter but faster 9mm/.38 bullet?  

 

In this example it's momentum (power factor) = mass x velocity.  The 45acp in this example has a 172.5 power factor and a typical 124 gr store bought ammo is causing along at 1150 fps has only a 142.6 power factor. Less momentum. 

 

Unfortunately there are rarely good first hand examples of .45 vs 9mm where the power factors are equal.  They do exist but most folks who only shoot store bought ammo aren't likely to have. 

[GoPewPew]

On 5/18/2022 at 5:19 PM, Johnny_Chimpo said:

 

As soft as the bullets we shoot are, I estimate that fragmentation is minimal and energy and momentum transfer is near perfect assuming a head on collision. 

 

Off angle impacts are pretty complex but I wager that the % of momentum and energy transfer will be roughly equal given bullets of different weights but equal power factors (since PF is nothing but momentum) and equal impact angles

 

My personal observations from shooting steel at an indoor range would suggest otherwise. The bullets fragment with pieces flying everywhere. We sweep up the range after every event and there are very small pieces of lead everywhere.  They absolutely fragment, carrying energy with the fragments.