Short barreled ARs...reliable or not?

tech1349

tech1349

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I've been thinking of buying a short barreled AR, probably a 7", 7.5". It'll strictly be for plinking and having fun at the range. No serious distance shooting or anything like that. Just a new toy to mess around with. But I stumbled across someone saying that ARs with barrels shorter than 10" have cycling issues.
Any opinions or info that can refute or confirm this or any other issues on 7" CQB ARs would be much appreciated.
 
AR's with barrels shorter than 10" (other than in 300Blk), especially the 7" variety basically beat themselves to death.

There is no reason, other than having no taste and too much money, to have or run a 7" AR. IMHO.
 
Ugh, here we go again...

A properly tuned AR with a short barrel works just fine. In my experience I have not had any more problems with issued L119s, CQBRS & PDWs than any 20" bbl AR I've used.

I have also made good hits on X-rays at 300m with a 10.5"bbl and hits on static targets out to 500m with same. PWS has numerous demo videos of their Mk107 (Diablo) demonstrating accuracy, reliability and durability on YouTube.

-S.
 
Cpt.Flan said:
From what I heard from some units around.. I would not go under 10.5". Most run 11.5.

Cheers.
Click to expand...

The units I've worked with haven't had trouble with 10.3"bbl L119s, Mk18 s or CQBRs. The PDWs with 7-7.5"bbls are basically to put heads down as you extract the Principal. They are still pretty accurate, if lacking fragmentation velocities.

-S.
 
I have a 7.5", 10.3" and a 12.5", they all work well. I've ran the 7.5" thru 3 classes and it works fine. Haven't shot it past 200m but its just as accurate at 200m as my 14.5". I've run maybe 2500-3000 rnds thru it so far, I did break a bolt (replaced under warranty).
 
If they are set up properly they run just fine. If you simply take your 16 inch barreled AR and throw a 7.5 inch barrel on it you will probably have problems.
 
Shorter barrel means moving the gas port closer to the chamber.
That means much higher pressure being used to cycle the action.
At the same time as this extra high pressure is cycling the gun, the brass case is still subject to the same high chamber pressure, so the case is held tight against the chamber wall.
 
A good solid manufactured AR barrel will have the appropriate gas port size to run reliably and not beat itself to death. The problem with reliability can often be caused by the type of powder used in ammo. Especially in the case of reloading. To fast or too slow can cause issues with bolt function either to fast or too slow.
 
Any suggestion on brand? Not quite ready to build one. Looking for something more ready to go, but can still make minor tweaks to. $1100-$1500 range.
 
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I put together a 10.5" upper a while ago.

Thinking the recoil/cycling may be more severe than a 14.5" or 16" barrel, I installed a H2 buffer, along with a heavier than stock Wolf spring.

The Wolf spring was a bit stronger than the 10.5" required, as it would too firm to allow the BCG to come all the way back to pick up the next round.

I R&R'd the Wolf spring with a standard spring and with the H2 buffer it worked mint!

As mentioned above, lots of guys/gals run 7.5" uppers. Using the correct buffer and an appropriate spring will allow you to tune the gun so it cyles well and does not "beat it's self up".

If you go forward with your build and want to experiment with buffers and springs, so the gun functions ideally, you are welcome to try the slightly heavier Wolf sping I have sitting............somewhere!
 
blackacres said:
I put together a 10.5" upper a while ago.

Thinking the recoil/cycling may be more severe than a 14.5" or 16" barrel, I installed a H2 buffer, along with a heavier than stock Wolf spring.

The Wolf spring was a bit stronger than the 10.5" required, as it would too firm to allow the BCG to come all the way back to pick up the next round.

I R&R'd the Wolf spring with a standard spring and with the H2 buffer it worked mint!

As mentioned above, lots of guys/gals run 7.5" uppers. Using the correct buffer and an appropriate spring will allow you to tune the gun so it cyles well and does not "beat it's self up".

If you go forward with your build and want to experiment with buffers and springs, so the gun functions ideally, you are welcome to try the slightly heavier Wolf sping I have sitting............somewhere!
Click to expand...

I appreciate the offer! Just gotta buy the damn thing is all. I was initially very discouraged by the little I'd read, but since putting this thread out there and doing some more research on the matter, I have much more hope that I can have the 7" CQB I've been wanting to run well. With some upgrades/changes it seems though.
 
I lold at the title of the thread before I even clicked on it...7.5's are good to go as long as you are buying a properly built gun, or using the right parts in combination for a build. The attainable accuracy with solid ammo is still excellent for the ranges this gun is designed for. The shorter you go the funner it gets. Good luck OP.

cheers
 
How violent is the ejection on the real short ones?
Does the extractor ever break?
Does the case rim get bent all to hell?
 
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