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Posted: 2/4/2006 1:30:42 PM EDT
I am new to the site and could not find an answer to this. I recently bought a Bushmaster Carbon 15 Type 97S Pistol with a 7.25" barrel. As I understand it, the advantage of the AR-15 .223 for personal defense is the fragmentation that occurs. As I further understand it, fragmentation begins at around 2700 ft/sec, reaches 75% at 2900, and is 100% by 3300; depending on the bullet.

I did not realize the relation between muzzle velocity and barrel length. It appears that with this short of a barrel length sufficient velocities cannot be obtained.

Is there any ammunition that can properly fragment with this gun? Is there any way to extend the barrel length?

Thanks
Link Posted: 2/4/2006 1:41:40 PM EDT
You may want to check out the ammunition forum as there is alot of info ammunition recommendations and velocities etc there.

Welcome to the site.

Link Posted: 2/4/2006 2:09:44 PM EDT
i would suggest looking for a better option for defense, since thats what it sounds like you are trying to do.

ar pistols to me are just fun guns and as long as they go bang it works.
Link Posted: 2/5/2006 6:46:16 AM EDT
I wonder if Bushmaster has given this any thought in the design of this pistol? Have they done any testing on it? Since so much energy is wasted with a 7.25" barrel, I wonder if they should consider making a pistol with a 12-14" barrel and/or a rifle with a 12-14" barrel?

I found one website where fragmentation testing was done with both an 18.9" barrel and a 14" barrel. They tested 4 different bullets. Best results (for these 4 bullets) were with a Hornady TAP 60gr (plastic tip JHP). Velocity was 2704 with the 18.9" barrel and 2534 with the 14" barrel. The other bullets were: 55gr FMJ, 69gr JHP, and a 55gr soft point.

Another fragmentation test on another site was done with the Hornady TAP and a 16" barrel. The 55gr had a velocity of 2910 and had a fragmentation of 75%. The 40gr had a velocity of 3335 and had a fragmentation of 100%.
Link Posted: 2/5/2006 7:15:21 AM EDT
IMHO a 9mm pistol is better than a .223 pistol for home defense.
Link Posted: 2/5/2006 8:20:33 AM EDT

Originally Posted By Phil_A_Steen:
IMHO a 9mm pistol is better than a .223 pistol for home defense.





+1,000,000,000,000
Link Posted: 2/5/2006 9:04:55 AM EDT
Would you prefer a Bushmaster .223 rifle with a 16" barrel and short stock over a 9 mm pistol?
Link Posted: 2/5/2006 9:21:47 AM EDT
Simple answer: BUY 70+ GRAIN BULLETS

I have several mags loaded with Hornaday TAP 77 grain and black hills 75 grain bullets.

I have done some precise scientific testing at the range (j/k) involving rabid phone books and bullets.

I have the results at my blog with pics at www.anathema-incarnate.blogspot.com

Check out "backyard ballistics"

Short answer on the results?

55 grain doesn't fragment (surprise, surprise I know. )

70+ fragments reliably every time.

Not for self defense my ass.
Link Posted: 2/5/2006 12:24:55 PM EDT
I could not find your info at: www.anathema-incarnate.blogspot.com

Was this in a pistol or rifle? How long was the barrel?

This is the site that tested the Hornady TAP ammo with a Bushmaster rifle with a 16" barrel:
http://www.bushmaster.com/le/tests/hornady_tactical_ammunition.htm

GR VEL % FRAG
40 3335 100
55 2910 75
60 2818 66
75 2616 72

Interesting that the 75 grain fragmented more than the 60 grain and almost as much as the 55 grain. Since there is more of a slug in the 75 grain it seems that this would do more damage. I wonder why it fragmented so well at a slower speed?
Link Posted: 2/5/2006 4:17:18 PM EDT
http://anathema-incarnate.blogspot.com/2005_06_01_anathema-incarnate_archive.html

it was in the archives. Pics are on the link above.

It was a Bushmaster carbon 15, 7.5 inch barrel.

All the numbers you speak about are assuming 55 grain bullets. Velocity and ballistics can change DRAMATICALLY depending on the barrel length AND the type of ammo selected.

A 35 grain 5.56 bullet is not the same thing as a 100 grain 5.56 bullet.
Link Posted: 2/5/2006 6:50:06 PM EDT
This is the first ballistics report of any kind I have seen on the Bushmaster pistol.

Thanks much.
Link Posted: 2/6/2006 1:24:31 AM EDT
You could always put a longer barrel on there..
Link Posted: 2/6/2006 4:26:17 AM EDT

Originally Posted By eklikwhoa:

Originally Posted By Phil_A_Steen:
IMHO a 9mm pistol is better than a .223 pistol for home defense.





+1,000,000,000,000



IMHO a .45 was always a good gun to have if need be!
Link Posted: 2/7/2006 5:13:29 PM EDT

Originally Posted By GENESMITH:
You could always put a longer barrel on there..



I just received an email from Bushmaster that a 11.5" barrel can be installed. This should provide sufficient velocity with a 40 grain round.
Link Posted: 2/8/2006 5:18:00 PM EDT
Heavier Hollow points are the way to go.

That being said, I think a .223/5.56 pistol while having some advantages, has quite a few against it ranging from overall effectiveness to defense in a courtroom.

If you are stuck on .223 only I would personally think you would be better suited with a lighter carbine with an 11.5-14.5 welded flash hider/brake to make it over 16 inches. I think a good short barreled AR varriant in that caliber with good hollows is a great self defense weapon with the ability for multiple adversaries, limited penetration in walls, and excellent handling double duty for the spouse... Just keep a courtroom approved 20 rounder in it with top shelf ammo and save the C-mores & banana clips as backup.

Also, FWIW, dropping the bolt on an AR has great pucker factor, second only to the racking of a 12 gauge pump...
Link Posted: 2/9/2006 7:32:41 AM EDT
There is a thread on this in the Ammo Forum. The difference here is that the new, longer barrel is still only 11.5". The question then becomes penetration vs. fragmentation because of the reduced energy with the shorter barrel.

Why is the courtroom being brought up? Where I live the gun and ammo are legal, I can use a 100 round magazine if I want, although I will stay with the 30 round. This weapon is only part of my arsenal should someone break into my home.
Link Posted: 2/9/2006 10:26:45 AM EDT
Before you ask any more ammo related questions, you should visit The Ammo Oracle

It is very detailed and should answer all your questions.
Link Posted: 2/9/2006 10:59:10 AM EDT

Originally Posted By CFFUTS23:
Before you ask any more ammo related questions, you should visit The Ammo Oracle

It is very detailed and should answer all your questions.


I have read it several times but I will again. I still have unanswered questions.

Thanks much!
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