What makes the short barrel AR15 (7", 11.5") unreliable??

[DarkMan]

Does anybody know what can one do to make a short barreled AR15 reliable? In Fullauto? Anyway?

I just heard they were not as good as a full size barrel?:(

Reason is I'm in the process of trading my new dirtbike for a registered DIAS and wanted to get a short barreled AR15 doner. So I want to know what can I get or look for.

Thanks!

[PBR]

Gas

[DarkMan]

redneck whitesox PBR,

Thanks! But can you elaborate a bit more on the GAS?

Falacias (Ficticious):

Was told that a good extractor spring might do the trick.

A Heavy Buffer?


How can one be reliable or shoot when I want it too?

Thanks!
:p

[Jericho]

Darkman,
I would thing that the short barrel would release the gas so soon that there would not be the proper build up of preasure to operate the system... The longer barrel will keep the gas preasure in the barrel a little longer and give the operating system full preasure to operate... just my $0.02 :bye:

[Da Bunny]

The USMC tested the CAR-15/XM177. Their experience was that the barrel must extend at least 5.5 inches beyond the gas port in order for the rifle to cycle reliably without extraction problems.

Minimum barrel length turns out to be 14.5 inches.

One work around is to ream out the gas port on the barrel. I don't have the numbers off hand.

[Tango 1Zero]

IM no expert on this but I also heard the hydraulic buffer is the way to go on a F/A

[gr8vfr]

I just went looking and couldn't find it....

I saw a bullestic report a while back and it documented that the .223 and 5.56 were inaccurate when shot from a barrel shorter than 11 inches.
My guess would be the length of the barrel stablizes the projectile.
You also need to remember that it is a tumbling round, so it is important to get a spin.
There may not be enough twist on a less than 11 inch barrel.

As for gas tubes.
I read the tube is to short. There is a company that makes a full length tube that wraps around the barrel under the hand gaurds.