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major power factor


LLRukus

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7 hours ago, LLRukus said:

powder to use with 147 gr for an open gun?

 

Most people find that using lighter bullets enables them to use MORE

powder, which produces MORE gas, which makes the compensator

work "better".

 

Been reading about a gun club here on BE that is using 147 gr bullets

in OPEN guns, but not sure what the advantage is ???

 

 

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VV 3N38, N105, Maybe N350?

Like most said here, it's not a common bullet weight for open but I have heard/seen people use it in Open.

38 super or 9? major/minor?

I would keep an eye on excessive pressure signs just to be safe.

 

Best of luck

 

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I just don't see any benefit. I want the most gas I can get to run the comp. That usually means pushing a bullet pretty fast. You can't push 147s fast. I mean you can but it's not a good idea

Edited by tcazes
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You most definitely do not want to use e3 to make major in an open gun.  The majority of open shooters use a 124gr bullet.  115gr is next in popularity.  Everything else is a blip.

 

If you can load long and use 3N38, your pressure will be in the +P range.  It will be higher with HS-6, and higher still with WAC and Silhouette.

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8 hours ago, Hi-Power Jack said:

 

Why not ?  Were 124 gr bullets more enjoyable ?

Very sharp recoil.  124's and 115's are softer feeling to me.   I run 115's almost exclusively now.    I've seen people talk about "the dot not leaving the window" and thought it was total BS.   That was, until I tried 10.5gr of AA7 behind a 115gr JHP.    

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6 hours ago, mwray said:

I had considered trying 147’s when I shot open. Then the more I thought about it the more it sounded like an explosion and a killed gun. So I gave up on it

 

What would cause the explosion?

 

4 hours ago, tcazes said:

I just don't see any benefit. I want the most gas I can get to run the comp. That usually means pushing a bullet pretty fast. You can't push 147s fast. I mean you can but it's not a good idea

 

Why is it not a good idea to push 147 grain bullets fast?

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Why is it not a good idea to push 147 grain bullets fast?


Well let’s take into consideration that the round needs to be around 1.165” to feed well. How much case capacity does that leave you? I was thinking somewhere around 7 grains. So then compressing a slow powder may not get you to major PF. Then you would need a faster powder. Now you’re playing with fire
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Well let’s take into consideration that the round needs to be around 1.165” to feed well. How much case capacity does that leave you? I was thinking somewhere around 7 grains. So then compressing a slow powder may not get you to major PF. Then you would need a faster powder. Now you’re playing with fire. Also fast burning powders don’t make enough gas to fuel a comp.
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46 minutes ago, mwray said:
47 minutes ago, mwray said:


Well let’s take into consideration that the round needs to be around 1.165” to feed well. How much case capacity does that leave you? I was thinking somewhere around 7 grains. So then compressing a slow powder may not get you to major PF. Then you would need a faster powder. Now you’re playing with fire. Also fast burning powders don’t make enough gas to fuel a comp.

 

In general, heavier bullets tend to achieve a higher power factor when pushed to the same pressure as lighter bullets.  In other words, when pushed to the same power factor, heavier bullets can do so at lower pressure.

 

Heavier bullets are generally best pushed with slower powders. There's no need for a faster powder.

 

There is plenty of space for the powder. People get paranoid about the case capacity in 9mm with heavy bullets. There's no need to. This seems to be a internet/gunstore myth.

 

Sure, heavier (longer) bullets reduce remaining case capacity, but they don't require as much powder as lighter (shorter) bullets and this takes up less space in the case. It's a non-issue from what I can see at the present.  

 

Take a look at the maximum loads for 9mm Luger in loading manuals for the various bullet weights and do the math. The heavier bullets are producing a higher power factor, and they're doing it with (usually) slower powders. 

 

Forgot to add this: https://atlantaarms.com/products/9mm-major-147gr-jhp-elite.html

Edited by superdude
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In general, heavier bullets tend to achieve a higher power factor when pushed to the same pressure as lighter bullets.  In other words, when pushed to the same power factor, heavier bullets can do so at lower pressure.
 
Heavier bullets are generally best pushed with slower powders. There's no need for a faster powder.
 
There is plenty of space for the powder. People get paranoid about the case capacity in 9mm with heavy bullets. There's no need to. This seems to be a internet/gunstore myth.
 
Sure, heavier (longer) bullets reduce remaining case capacity, but they don't require as much powder as lighter (shorter) bullets and this takes up less space in the case. It's a non-issue from what I can see at the present.  
 
Take a look at the maximum loads for 9mm Luger in loading manuals for the various bullet weights and do the math. The heavier bullets are producing a higher power factor, and they're doing it with (usually) slower powders. 
 
Forgot to add this: https://atlantaarms.com/products/9mm-major-147gr-jhp-elite.html

Speaking of math 147 bullets cost way more per thousand than 115’s so if you are wanting to waste money just buy new lapua 9mm brass and run 115’s safely
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27 minutes ago, superdude said:

 

Heavier bullets are generally best pushed with  slower  powders. There's no need for a faster powder.

 

That's contrary to everything I've read and experienced.

 

I like heavy (147 gr) bullets in 9mm Minor with a FAST Powder -

 

And, I've read that heavy .40 Major bullets with Fast powder is

The Way to Go  ....    

 

I use the slow powders for 9mm Major in Open, with a comp.    :) 

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There is a big distinction between loading for a non-compensated gun and a compensated gun when trying to reach power factor for competition.  The rules of thumb are opposite.

 

non-compensated gun: for the same power factor, heavy bullet with fast powders for the lowest/softest recoil.  

 

compensated gun: for the same power factor, light bullets with slow powders for the lowest muzzle rise.

 

general reloading: check a loading manual and there is a trend for fast powders pushing light bullets to their highest speed, and slow powders pushing heavy bullets to their highest speed. (And there will always be exceptions.)   And, the heavier bullets tend to reach a higher power factor in general, as noted in previous post. This is what I was alluding to - given the thread title and discussion - sorry for any confusion.   

 

 

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Just a hypothetical thought but thinking physics.... a 147gr bullet has about 1/3 more mass than 115.  How much more energy does it take to move that much more mass?  All that energy must be built up in the chamber before the bullet ever starts to move.  Then due to friction of the bullet in rifling, how much more energy(pressure) does it take to get to the velocity you need?  Of course time is also a consideration but you have to do all this before bullet leaves the barrel.    It seems that since energy in this case is directly related to pressure & time, you would be building considerably more pressure than what would be needed for a 115gr bullet.  In a 9mm where trying to make major power factor is already fairly high pressure, this might warrant some thought.....

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21 minutes ago, mlmiller1 said:

Just a hypothetical thought but thinking physics.... a 147gr bullet has about 1/3 more mass than 115.  How much more energy does it take to move that much more mass?  All that energy must be built up in the chamber before the bullet ever starts to move.  Then due to friction of the bullet in rifling, how much more energy(pressure) does it take to get to the velocity you need?  Of course time is also a consideration but you have to do all this before bullet leaves the barrel.    It seems that since energy in this case is directly related to pressure & time, you would be building considerably more pressure than what would be needed for a 115gr bullet.  In a 9mm where trying to make major power factor is already fairly high pressure, this might warrant some thought.....

 

Kinetic energy = 1/2 * mass * velocity * velocity

 

When you crunch the numbers at constant power factor it works out differently than intuition would suggest. 

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