AR15 issues from slow-fire strings?

[DRNewcomb]

I have a couple AR15-action rifles I've used them for both NMC and now F-class competition. Most of the rounds I've shot through these rifles has been slow-fire, single-loaded. One of these, my "space gun", has been having problems with the bolt hold-back (catch) sticking. It does not raise and then sticks in the up position when it does rise. Last night I removed it and cleaned up the rough edges. The sloped face of the stop has chatter marks where one of the bolt lugs drags when the bolt retracts and the upper edge of the catch seems roughened.

Is this a normal byproduct of single-loading an AR action or an indication of a low-quality bolt catch or some geometry issue with the receiver?

 

[jonbearman]

Do you have a mag inserted while single loading or a sinclair sled.What brand of parts are in the lower?

 

[DRNewcomb]

Do you have a mag inserted while single loading or a sinclair sled.What brand of parts are in the lower?

I normally shoot with a 20-round mag in place. The lower is an E.A. and I'm not entirely sure but most of the parts were probably obtained form E.A. (maybe about 20 years ago). The trigger was modified by Compass Lake Engineering to a two-stage design.

 

[jonbearman]

Does it move freely on the pin,thinking maybe the roll pin is tight in the clearance hole in the catch it self.If it binds I would buy a new one and the spring.

 

[DRNewcomb]

Does it move freely on the pin,thinking maybe the roll pin is tight in the clearance hole in the catch it self.If it bins I would buy a new one and the spring.

Yes. It is not binding on the roll pin. After I cleaned up the faces and edges with a small file it worked perfectly for about 40 rounds, then began sticking again.

I was curious if I just bought a standard catch to replace it, would I be in the same situation after a few hundred rounds. I've looked on Brownells/Sinclair and didn't see any bolt catches specifically for single-round shooting. This leads me to suspect that the problem is not common and that I probably just have a catch that was not hardened properly.

 

[jonbearman]

I would try a different one. and replace the spring.

 

[mac86951]

I would try a different one. and replace the spring.

+1 to that. Many part on the market, but some will give better results than others.
You might want to polish your BCG/Catch along the riding surfaces too. Finally, are your bolt
gas-rings ok? Does your firing pin become fouled during shooting? You might be getting gasses leaking
out and gunking up the catch, but they would gunk up much more too.

-Mac

 

[DRNewcomb]

I spoke with someone in the business of building ARs and he told me that in the last five years or so the steel used in the bolt catches has been upgraded and hardened much higher than they were previously.

 

[KevinThomas]

First step here; stop thinking of an AR as a monolithic "rifle." They're nothing more than a collection of spare parts, temporarily pinned, screwed or pressed together, any of which are subject to replacement at any time. That's part of the beauty of them. Don't be bashful about switching out parts that have proven troublesome.

 

[DRNewcomb]

First step here; stop thinking of an AR as a monolithic "rifle." They're nothing more than a collection of spare parts, temporarily pinned, screwed or pressed together, any of which are subject to replacement at any time. That's part of the beauty of them. Don't be bashful about switching out parts that have proven troublesome.

I've built and fixed enough of them to have no problem viewing the AR as a random collection of parts flying in loose formation. My only issue was the excessive wear on a single part and understanding if it was a common problem found in guns when frequently single loaded, the result of a substandard part or perhaps improper fitting.

 

[mac86951]

First step here; stop thinking of an AR as a monolithic "rifle." They're nothing more than a collection of spare parts, temporarily pinned, screwed or pressed together, any of which are subject to replacement at any time. That's part of the beauty of them. Don't be bashful about switching out parts that have proven troublesome.

I've built and fixed enough of them to have no problem viewing the AR as a random collection of parts flying in loose formation. My only issue was the excessive wear on a single part and understanding if it was a common problem found in guns when frequently single loaded, the result of a substandard part or perhaps improper fitting.

Well, single loading will work the bolt catch more often, than shooting the same number of shots through loaded magazines. Sound like you're getting enough trigger time to find some of the less common wear items. An adjustable gas block tuned to your load might soften the hit on the bolt catch.

-Mac

 

[cdparker]

Kevin,
Are you talking about AR's or Helicopters?
It was good to run into you in Houston.
Craig

 

[Beau]

Seems like Eagle Arms lowers have a lot of issues with the bolt catch area. I had a couple of those lowers and they had issues with the bolt not locking back. Heard that same issue from others as well. And now you come along and say your bolt is dragging on your bolt catch. Hmmm.
I got rid of my trouble makers.

 

[Ggmac]

Is it eagle arms or essential arms , the essential arms of many years ago , the only ones available other than Colt , had a few issues . I had one I was working on that had been enlarged in the bolt stop slot from shooting . It allowed the bolt release to wiggle and worked for a while after reassembly ,with a new pin , unti a few mags were thru it than it woud malfunction again . It kept bending the retaining pin .