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Posted: 9/21/2002 2:12:58 PM EDT
I have a preban Bushmaster with an 11.5 barrel and a 5.5" flash suppresor. I was looking at the ammo FAQ's on the sight and was alarmed by the fact of fragmentation and accuracy over more than 100yds. Is this the norm with such a short barrel. I admit my groupings at 200+ m are not exceptional but I am able to hit man size targets consistently at that range. However I am wondering if they will be ballistically effective at this range? I have been thinking of going to a flatop M4 upper, keeping the car of course. Just wondered if having the shorter barrel limits the rifle more in the field?
Link Posted: 9/21/2002 3:58:43 PM EDT
Accuracy and length have nothing to do with each other. The most accurate weapon I own is a Remington XP-100 bolt action pistol. It will shoot five shot dime size groups all day long.My 11" AR will shoot 3/4" groups at 100 yards easy.It all depends on what you want to use thre weapon for. Punching holes in paper or as a tactial or home defense weapon. I'm sure if I put a round through the head of someone in my home 20 to 30 feet away from me it would do enough damage to stop him.
Link Posted: 9/21/2002 8:04:28 PM EDT
The disadvantage to the short barrel ARs is not their accuracy. Its their short fragmentation range. The short barrels just dont give the round very much velocity to begin with.
Link Posted: 9/22/2002 5:57:46 AM EDT

Originally Posted By new-arguy:
The disadvantage to the short barrel ARs is not their accuracy. Its their short fragmentation range. The short barrels just dont give the round very much velocity to begin with.



new-arguy,
What do you mean by 'short fragmentation range'? I figured, perhaps incorrectly, that a short barrel would obviously lower bullet velocity, with the corresponding implications. Among them are lower long range accuracy due to bullet drop and less stability due to the bullet not fully twisting down the barrel. In addition, the increased muzzle blast could account for shooter 'alarm'.
But I never heard of 'fragmentation'. Could this be due to lack of bullet twist??

TSL
Link Posted: 9/22/2002 7:07:57 AM EDT
[Last Edit: 9/22/2002 7:08:27 AM EDT by k9dpd]
no its from lack of velocity, it needs 2600 fps to fragment when it hits and its only coming out of the at 2800 depending on which round you shoot. I shoot TAP out of my 11.5 so I dont half to worry as much with velocity.
Link Posted: 9/22/2002 7:48:53 AM EDT
[Last Edit: 9/22/2002 7:50:11 AM EDT by new-arguy]


That's fragmentation, and milspec ammo, like M193 and M855 need to be cruising along at at least 2700 FPS to fragment reliably. With a short barrel, you just dont get enough velocity right out of the barrel to allow it to travel that fast for very long. Out of a 11.5" barrel you drop below 2700 fps at a mere 12-15 meters with M855 ammo, and about 40 meters using M193. This may be perfectly acceptable, and even ideal for a dedicated CQB gun, but once you step outdoors where ranges will open up, your creating very small .22 cal wounds out past those ranges. Rounds like TAP will still expand, but the wounds they create are far less dramatic than fragmenting rounds. Read the ammo FAQ, it really answers a lot...

www.ammo-oracle.com/
Link Posted: 9/22/2002 7:59:41 AM EDT
Thanks -
I guess that is: higher velocity insures bullet fragmentation upon impact.
Shorter barrel do not allow the bullet to maintain that critical 2600-2800 where optimal fragmentation occurs.

I wax eloquent.
Thanks.
Link Posted: 9/22/2002 7:57:42 PM EDT
So without the fragmentation what will the round do? Does this make it ineffective? I imagine that it would just then pass through and/or become lodged in the target? So a 16" barrel adds what in effective range?
Link Posted: 9/23/2002 8:48:52 AM EDT

Originally Posted By edblevi:
So without the fragmentation what will the round do?


Just Zip through the target, turning once.



Does this make it ineffective?


Not innefective - just MUCH less effective. It can still kill, you just had better have VERY good shot placment and time to wait...



So a 16" barrel adds what in effective range?


Look Here groups.msn.com/TheMarylandAR15ShootersSite/rifleperformance.msnw
Second chart down.
Link Posted: 9/23/2002 8:58:32 AM EDT
Forest,
Lets face it the 5.56 is still not a one shot one kill round. I have packed an M16A2 and an M4 around for quite a while in traditional infantry to CQB roles. Facts are, not one thing you see in movies is true. One shot from a 5.56 will send some bad guy spirling to the ground, in fact they can take several till they become less of a threat.
The main thing is put as many of them on your BG accurately as you can as quickly as you can, and look for someone else who is going to need attention.
Link Posted: 9/23/2002 9:46:32 AM EDT
Exactly...PRACTICE----PRACTICE---PRACTICE... anybody can pull a trigger, it those that can aim and do it right that will win.
Link Posted: 9/23/2002 10:37:01 AM EDT

Originally Posted By jmmgbohl:
Lets face it the 5.56 is still not a one shot one kill round.


Short of a 120mm APFSDS round I don't know what is all the time. Certainly not .30 cals, .50BMG comes close - but still doesn't do it.

The 5.56 within its optimal performance envelope does a very good job - its FMJ rounds do a far better job than the common FJM .30 cal rounds (7.62x51 & 7.62x39)




I have packed an M16A2 and an M4 around for quite a while in traditional infantry to CQB roles.


And this makes you qualified to speak on terminal ballistics in what way? If you want info go to the experts - People such as Dr Fackler (Col US Army - Ret), or Dr Roberts (LtCmd US Navy). Who have been involded in the reasearch and seen the real results first hand.



Facts are, not one thing you see in movies is true. One shot from a 5.56 will send some bad guy spirling to the ground,


Movies are for entertainment - I don't see ANYONE in this forum using movies as a basis for anything other than consuming popcorn and soda-pop.
Link Posted: 9/23/2002 10:47:37 AM EDT
soooo... what you're saying is:

the "evil feature" of a sub-16" barrel is actually making the weapon LESS dangerous.

just about as moronic as the whole collapsible stock "evil feature". You can have any fixed length (including shortest collapsable length) legally... but not one that will change...?

But I sure am glad I can still remove my detachable magazine and add a grenade launcher! (well... maybe not)
Link Posted: 9/23/2002 4:05:51 PM EDT
11" accuracy. I get mine by shooting off a bench with a converted Ramson rest. I'm also using a 6X-24X by 50MM scope. The barrel is the main part. I start with a 1/8 twist Douglas S.S. heavy barrel. I turn the O.D. myself at the wifes machine shop to an A2 contour under the handguards. In front of the sight I keep it at a standard .750 diameter. It's kept preban with a threaded barrel end but it does have a precision ground concave crown. Plus all I shoot is handloads. What works in this barrel is Nosler 55 grain balistic tips in Lake City brass, Remingtom bench rest primers, and 27.75 grains of 748 powder. The gas port is also opened to .105 to cycle properly with all the ammo I shoot. I've also got an early DPMS heavy 11" that shoots 1" groups form the rest with handloads. both barrels wear my own design of flashider that I also make myself to help control barel harmonics. It has the same O.D. as the barrel and I don't use a peel washer.
Link Posted: 9/23/2002 10:07:50 PM EDT
I have a 11.5 inch barrel and can shoot 1 moa at 100 yards with a reflex II on it with Tap 55 grain, from a sandbag all day long.
Link Posted: 9/23/2002 10:22:26 PM EDT

Originally Posted By steenkybastage:
soooo... what you're saying is:

the "evil feature" of a sub-16" barrel is actually making the weapon LESS dangerous.

just about as moronic as the whole collapsible stock "evil feature". You can have any fixed length (including shortest collapsable length) legally... but not one that will change...?

But I sure am glad I can still remove my detachable magazine and add a grenade launcher! (well... maybe not)



The barrel size and adjustable stock no doubt have to do with the fact that a shorter barreled AR with an adjustable stock would considerably more concealable and portable than one without those two features. A 11.5" barreled AR can still be very, very deadly, as deadly as any other AR. The only difference is that its maximum performance range will be considerably shorter. It can be, and no doubt is a awesome weapon when used indoors, or close quarters only. In fact, it is fabulous for that role. It just may not be AS useful in other environments as some other AR's with longer barrels.
Link Posted: 9/24/2002 1:42:41 AM EDT
11" accuracy. I get mine by shooting off a bench with a converted Ramson rest. I'm also using a 6X-24X by 50MM scope. The barrel is the main part. I start with a 1/8 twist Douglas S.S. heavy barrel.

Explanation excepted, post deleted, was not aware we were speaking of custom barreled shorties.

Please accept apology for earlier comments,
Mike
Link Posted: 9/24/2002 1:26:51 PM EDT

Originally Posted By new-arguy:

Originally Posted By steenkybastage:
soooo... what you're saying is:

the "evil feature" of a sub-16" barrel is actually making the weapon LESS dangerous.

just about as moronic as the whole collapsible stock "evil feature". You can have any fixed length (including shortest collapsable length) legally... but not one that will change...?

But I sure am glad I can still remove my detachable magazine and add a grenade launcher! (well... maybe not)



The barrel size and adjustable stock no doubt have to do with the fact that a shorter barreled AR with an adjustable stock would considerably more concealable and portable than one without those two features. A 11.5" barreled AR can still be very, very deadly, as deadly as any other AR. The only difference is that its maximum performance range will be considerably shorter. It can be, and no doubt is a awesome weapon when used indoors, or close quarters only. In fact, it is fabulous for that role. It just may not be AS useful in other environments as some other AR's with longer barrels.



True... but being able to put on a stock that is just as short as a collapsible stock legally makes no sense if that's the case. Cant you even get a pistol kit for the ar15 that has no stock?

Unless I'm making an incorrect comparrison between my 16" setup w/ standard a2 stock and what I'd think the 11" version... Both would require a trenchcoat, or to have the upper separated from lower in order to be successfully concealed. With a trenchcoat, one could conceal a full 20" ar15.
Link Posted: 9/24/2002 1:33:38 PM EDT

With a trenchcoat, one could conceal a full 20" ar15


I wish. Not unless you are over 6ft tall.

Yes I HAVE tried.

Link Posted: 9/24/2002 2:04:08 PM EDT

Originally Posted By ArmdLbrl:

With a trenchcoat, one could conceal a full 20" ar15


I wish. Not unless you are over 6ft tall.

Yes I HAVE tried.




umm... i'm 5'9", and my 16" AR only drops to my knee when I hold the butt in my armpit. 4" more isn't even into the bottom half of my shin.

Perhaps the type of trenchcoat you're talking about is different than mine, which drops to nearly my ankles.

and before you ask... I've never actually used or owned a 20" AR, so perhaps there is more of a difference then I'm aware of...
Link Posted: 9/24/2002 2:26:45 PM EDT
If you can hit a man size target at 200 yards what are you worried about? Hell I prefer the 11.5" barrels over the 16 and the 20. Let me know if you decide to sell it.
Link Posted: 9/24/2002 3:04:14 PM EDT
Well I sure won't be selling it, this is my preban buddy with all the evil extras. I have it set up in the CQB style. I just wondered of the options with longer barrels, etc. I will probably buy another upper 16" just to have and switch out when I want or just buy another whole rifle? HMMM that sounds even better!
Link Posted: 9/24/2002 4:50:54 PM EDT

Originally Posted By steenkybastage:

Originally Posted By ArmdLbrl:

With a trenchcoat, one could conceal a full 20" ar15


I wish. Not unless you are over 6ft tall.

Yes I HAVE tried.




umm... i'm 5'9", and my 16" AR only drops to my knee when I hold the butt in my armpit. 4" more isn't even into the bottom half of my shin.

Perhaps the type of trenchcoat you're talking about is different than mine, which drops to nearly my ankles.

and before you ask... I've never actually used or owned a 20" AR, so perhaps there is more of a difference then I'm aware of...



Well besides having the muzzle uncomfortably close to the ground. It prints, BADLY. You might get by with the legal definition of concealed, but everyone is going to know you got a rifle under there as soon as you start walking. Don't even think about trying to sit down.

I'd like to try again with a 16" and a working telestock, a single point sling, and a 20rnd mag. That and maybe a velcro strap or a bungee cord at belt level to stop the front end swing and I might be able to get away with it.

Yes I have watched Heat too many times.
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