Will a 7" rock river ar upper cycle reliably ?

Probably. They might have an expansion chamber, though they can be made to work otherwise. Seem to need a stiffer extractor spring or D ring.

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That's a Bushmaster Carbon-15 pistol. Very lightweight and fun to shoot.

We had one out at the range last week.

Can you say HOLY MUZZLE BLAST? It wasn't bad for accuracy, either.

The only problems we had with it were FTF from crappy mags. It ejected brass fine every time.
 
Twocold makes a kick *ss short barrelled AR. If you have problems, he might be able to help you out. BTW, my Bushmaster Carbon Pistol didn't cycle properly and is still with the gunsmith who is waiting for parts. :(
 
I have never seen an ar with a bbl less than 14.5" that didn't stop working...fine for casual range use and plinking but thats it.

For all the guys who are about to post how their 10.5 functions flawlessly try this: Fire 1000 rounds on day one with 30 rd mags (not in Canada of course), clean and lube, do it again on day two.

If your gun runs then I stand corrected...just never seen it in the couple dozen times I've been around when people tried.

jl
 
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juliet lima said:
I have never seen an ar with a bbl less than 14.5" that didn't stop working...fine for casual range use and plinking but thats it.

For all the guys who are about to post how their 10.5 functions flawlessly try this: Fire 1000 rounds on day one with 30 rd mags (not in Canada of course), clean and lube, do it again on day two.

If you're gun runs then I stand corrected...just never seen it in the couple dozen times I've been around when people tried.

jl

What happened to the guns? Major failure or things like extractors etc screwing up and FTF's?
 
I bet my LMT could pass the test. So far I put 300 rounds through it non stop, had friends loading 5 round mags..lol.. No issues. I need more mags and I would be willing to try 1000 rounds. I guess it doesnt really matter much though as other than trying to test it out, I never shoot that many ussually anyways.
 
I have a 10.5" LMT which seems to be running great.
I also plan to change the rings every 1000rnds to ensure long-term reliable function (I keep spare rings in the MIAD grip along with an extra firing pin and a few other loose parts).

I will also mention that I did have problems with the heavy CAR buffer and spring; the problem being I lost the last round hold open feature due to there not being enough energy to properly cycle (still worked though, I did not have any FTE's but it was probably only a matter of time).

I fixed the problem by switching to the longer/lighter more reliable A2 Buffer/Spring. Not a single problem (yet;)).

On the plus side to owning shorty AR's, I've noticed that cleaning is easier... not as dirty as my 20" AR I owned in the past. I was pleasantly surprised by this.
 
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Uh huh, sure it did...

KevinB said:
My 10.3" LMT upper gagged the second drill - wrong bolt in it and it did not liek it (adding to James's rant on LMT [they had two 10" go down in a firefight in Iraq near Irish])
My 16" SR16 jumped in and despite the match chamber and SS barrel performed flawlessly...
 
G37 said:
I will also mention that I did have problems with the heavy CAR buffer and spring; the problem being I lost the last round hold open feature due to there not being enough energy to properly cycle (still worked though, I did not have any FTE's but it was probably only a matter of time).

Why did you go for a heavier spring? I only heard of using regular CAR spring with the heavy buffer.:confused:
 
Bigger is better right? (jk)

I went on Wolff Spring buying frenzy... I didn't have a regular CAR spring to try but as you say it was the HD spring in conjunction with the heavy buffer.

Either way it works now and I am happy :) Something for anyone ready this thread to be weary of; HD spring and Heavy buffer not he best combo for short .223 AR's.
 
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