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  #1  
Old 10-06-2010, 10:15 PM
yocan yocan is offline
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.45 acp and barrel length




Anyone have a chart for any loading of a 230 gr .45 acp with relatively normal loading? I figure if anyone has one its on here.

Basically I want any normal ish round out a 4" 5" and something longer to give me an idea. If it was a curve graph it would be much cooler. or a reloading website that does coarse math for me so I can figure it out. I'm trying to figure out the barrel length for my next project.
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  #2  
Old 10-06-2010, 11:17 PM
tracyballard tracyballard is offline
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I would be curious to know if there is much of a ballistic advantage in going with a 6 inch barrel over a 5 incher.
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  #3  
Old 10-07-2010, 01:50 AM
subscriber subscriber is offline
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Go about halfway down this page for actual test data where a barrel was cut down from 5" in steps and bullet velocity at each length:

http://yarchive.net/gun/pistol/1911_barrel_length.html


Plotted for your convenience:

Attached Thumbnails
_45-velocity-vs-barrel-length.jpg  
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  #4  
Old 10-07-2010, 05:31 AM
WESHOOT2 WESHOOT2 is offline
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define "ballistic advantage"

What if the six-inch shoots slower than a five-inch? or my 4.5" Witness?

A proper SD 230g bullet requires around 700fps impact velocity to work as designed.





Same-length barrels can vary velocity-wise by unbelievable amounts. Tested.
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  #5  
Old 10-07-2010, 08:24 AM
USMM guy USMM guy is offline
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Now tell me what happens.

When you are shooting the .45 acp round out of a carbine. I have been told that this round is a poor performer out of a carbine length barrel. Can anyone shed some light on this?
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  #6  
Old 10-07-2010, 08:38 AM
Brian48 Brian48 is offline
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I read an old G&A review of the Marlin .45 carbine, which had an 18 inch barrel, several years ago. The long barrel did cause velocities to dip to the point where it just wasn't worth it. Little wonder the gun never went anywhere. I would guess that the optimal length for a low pressure cartridge like the .45acp would be between 10 or 12 inches, which is what the later production Thompsons and M3 Grease guns were (there abouts) towards the tail end of WWII and the Korean war.
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  #7  
Old 10-07-2010, 08:40 AM
Dave Waits Dave Waits is offline
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Must have been some sort of test-barrel used. A standard five-inch Bbl includes the chamber. You end up with a little over 3-3/4" of rifling(Actual Barrel).

As for carbines and the 45ACPs performance. Remember, to get 800fps out of that short barrel they have to use a very fast-burning powder. The long 16" barrel of a Carbine actually slows the bullet down some. The manufacturers aren't going to load an efficient round for the carbine because of liability-issues. I.E.; Some fool trying to shoot them in his Gov't Model.

One of my shooting buds has a Semi-Auto Thompson he played around with for a bit with some med.burn-rate powders. He got velocity up to around 1300fps with 230gr.FMJs but it was really hard on the case and the pressure was pretty high.
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  #8  
Old 10-07-2010, 09:43 AM
yocan yocan is offline
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Quote:
Originally Posted by USMM guy View Post
When you are shooting the .45 acp round out of a carbine. I have been told that this round is a poor performer out of a carbine length barrel. Can anyone shed some light on this?
thats actually the basis for my question.

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Originally Posted by Dave Waits View Post
Must have been some sort of test-barrel used. A standard five-inch Bbl includes the chamber. You end up with a little over 3-3/4" of rifling(Actual Barrel).

As for carbines and the 45ACPs performance. Remember, to get 800fps out of that short barrel they have to use a very fast-burning powder. The long 16" barrel of a Carbine actually slows the bullet down some. The manufacturers aren't going to load an efficient round for the carbine because of liability-issues. I.E.; Some fool trying to shoot them in his Gov't Model.

One of my shooting buds has a Semi-Auto Thompson he played around with for a bit with some med.burn-rate powders. He got velocity up to around 1300fps with 230gr.FMJs but it was really hard on the case and the pressure was pretty high.
Umm wouldn't they not do it because it would be blatantly blinding with so much powder burning out there.

I'm thinking of getting a Kriss and making it sbr when I get back from afghanistan. trying to figure out how longn I'd want it. its supposed to be a 5.5" barrel, from the graphs I'd guess 7" or so is probably the ideal length.
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  #9  
Old 10-07-2010, 10:31 AM
Dave Waits Dave Waits is offline
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Quote:
Originally Posted by yocan View Post
thats actually the basis for my question.

Umm wouldn't they not do it because it would be blatantly blinding with so much powder burning out there.

I'm thinking of getting a Kriss and making it sbr when I get back from afghanistan. trying to figure out how longn I'd want it. its supposed to be a 5.5" barrel, from the graphs I'd guess 7" or so is probably the ideal length.
Never stopped them before. Ever fire a 125grain SJHP out of a 357mag. at night???? Not familiar with the Kriss but, aSBR(I assume you're talking about a Short-Barrelled Rifle') not already registered would be a violation of the NFA. Basically, if you take a rifle or a carbine and cut the barrel below 16" or if you turn a manufactured pistol into a rifle with a barrel under 16", you've created a short-barrel rifle under the National Firearms Act. That's a felony.

Manufacturers get by with it because until they affix a barrel to a receiver it is neither a rifle or a pistol, ATFE calls it 'Original-Intent'. For example, the 'Mare's-Leg' that came out last year. Taurus,I believe, makes them. They took a Winchester Model 92 receiver and made a pistol out of it in Handgun calibers, 44-40,45Colt ala the Bounty-Hunter series in the 60s. But, if they take that receiver and make a rifle out of it and you cut down the barrel and stock to make a 'Mares'-Leg' you've created a short-barrelled rifle, original-intent.
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  #10  
Old 10-07-2010, 11:20 AM
Pat-inCO Pat-inCO is offline
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http://www.ballisticsbytheinch.com/45auto.html
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  #11  
Old 10-07-2010, 12:26 PM
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I've chrono'd rounds from guns with different barrel lengths, and in my experience, you'll see 30-50fps difference when you change the barrel length by an inch. I suspect that the difference gets smaller as the barrels get longer, i.e. you may see more than 50fps difference between 3" and 4", and less between 5" and 6". Powder burn rate also plays a part, so a load using slow-burning powder will react to barrel length differently than one with a fast powder.
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  #12  
Old 10-07-2010, 02:57 PM
yocan yocan is offline
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Quote:
Originally Posted by Dave Waits View Post
Never stopped them before. Ever fire a 125grain SJHP out of a 357mag. at night???? Not familiar with the Kriss but, aSBR(I assume you're talking about a Short-Barrelled Rifle') not already registered would be a violation of the NFA. Basically, if you take a rifle or a carbine and cut the barrel below 16" or if you turn a manufactured pistol into a rifle with a barrel under 16", you've created a short-barrel rifle under the National Firearms Act. That's a felony.

Manufacturers get by with it because until they affix a barrel to a receiver it is neither a rifle or a pistol, ATFE calls it 'Original-Intent'. For example, the 'Mare's-Leg' that came out last year. Taurus,I believe, makes them. They took a Winchester Model 92 receiver and made a pistol out of it in Handgun calibers, 44-40,45Colt ala the Bounty-Hunter series in the 60s. But, if they take that receiver and make a rifle out of it and you cut down the barrel and stock to make a 'Mares'-Leg' you've created a short-barrelled rifle, original-intent.
I know its class III. To go to afghanistan I had to switch my residence back to Tx, now that its done I'm eligible for class IIIs again. The 6 month wait for the stamp will occur while I'm in Afghanistan. I plan on it being my welcome home present to myself.

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I've chrono'd rounds from guns with different barrel lengths, and in my experience, you'll see 30-50fps difference when you change the barrel length by an inch. I suspect that the difference gets smaller as the barrels get longer, i.e. you may see more than 50fps difference between 3" and 4", and less between 5" and 6". Powder burn rate also plays a part, so a load using slow-burning powder will react to barrel length differently than one with a fast powder.
I know powders make a difference but I want to use the same ammunition between my 1911 and the kriss. and I absolutely won't go past 10" probably would say in the 5.5-8" range would be ideal....What I'm trying to figure out is past 5" with regular pistol loadings would I really benefit very much? (Kriss is designed for a 5.5" barrel)
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  #13  
Old 10-07-2010, 03:02 PM
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stillwater stillwater is offline
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Quote:
Originally Posted by USMM guy View Post
When you are shooting the .45 acp round out of a carbine. I have been told that this round is a poor performer out of a carbine length barrel. Can anyone shed some light on this?
It has been run in a carbine. It has little advantage going "carbine-length" as the case allows precious little extra room for heavy loading.

The .45 LC has a distinct advantage for carbine over the .45 ACP (nearly twice the case volume).

Also, modern carbines are capable of high velocities, therefore longer range is desired so larger cases and smaller projectiles provide better "energy" levels at longer ranges, thanks to higher muzzle velocity.
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Last edited by stillwater; 10-07-2010 at 03:03 PM. Reason: clarification
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Old 10-07-2010, 03:21 PM
tracyballard tracyballard is offline
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seems like a much better option for a SBR or carbine would be 10mm.
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Old 10-07-2010, 05:06 PM
yocan yocan is offline
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seems like a much better option for a SBR or carbine would be 10mm.
I agree entirely. However I love the design of the kriss, it doesn't come in 10mm. Also I want interchangeability with my 1911. it would also make a great SHTF weapon for inside the city where there is a large population and being ambigous is a necessity to survival. If I decide to go the suppressor route, I don't think there is a better weapon out there than the kriss. it just seems ideal.

I do think the FBIs 5178 units of MP5/10mm is the best SMG on earth. I don' really have the option to do that route.
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Last edited by yocan; 10-07-2010 at 05:12 PM.
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Old 10-07-2010, 06:47 PM
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For those wondering *** a Kriss is, watch this video. It's cool as hell, but for me, I wouldn't want it unless I could have it in full auto. And since this gun was invented after 1986, none of us surfs can have it.

http://www.youtube.com/watch?v=f2kEg...ayer_embedded#!
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Old 10-07-2010, 07:10 PM
Dave Waits Dave Waits is offline
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Pretty neat vid. Only thing, the darned thing is shaped just like the Hilti Rotory-Hammer I had in my Toolbox at work!!!
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Old 10-07-2010, 09:58 PM
yocan yocan is offline
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Originally Posted by gaspipes View Post
For those wondering *** a Kriss is, watch this video. It's cool as hell, but for me, I wouldn't want it unless I could have it in full auto. And since this gun was invented after 1986, none of us surfs can have it.

http://www.youtube.com/watch?v=f2kEg...ayer_embedded#!
my thinking is a 7" barrel with a supppressor might be pretty sweet. b

but what has me confused about life is this, if they guarantee 1" at 25m, how do you get 10" at 100m the .45acp round is not that unstable
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