AR-15 Anderson LPK

[pdsmith505]

I used an Anderson Arms LPK on a recent 300 BLK pistol build and ran into an issue that ended up being caused by the bolt catch bending.

After 6 magazines or so (so 6 cycles on the bolt catch), it became near impossible to release the bolt using the bolt catch.

Since I was using hard cast and coated 240gr bullets, I figured that some kind of buildup was the cause, but, upon removing the bolt catch, it was apparent to the naked eye that the bolt catch was bent. I hammered it back to flat, and it works well now.

I can think of two possibilities for this:
1) The bolt catch is defective and not strong enough
2) Something about the 240gr loading allows enough time between the bolt cycling forward and the magazine follower allows the BCG to gain enough momentum to bend a properly built bolt catch.

It can't be the weight of the round on the magazine, since there is not a round in the magazine during the last shot... but the gun could be cycling too hard/fast causing excessive energy in the bolt.

Has anyone else had this issue? Any suggestions for a fix?

I'm thinking the best solution is ponying up for an adjustable gas block to fine tune the gun based on the rounds being fired.

Relevant specs on the gun:
Palmetto Armory stripped upper
Palmetto Armory H2 buffer
Palmetto Armory premium BCG
SOTA arms 10.5" .300 BLK barrel (Pistol gas)
Running suppressed

 

[boom boom]

Not overly familiar with the .300 in the pistol configuration. Is this I am sure that you will get a host of answers but my best guess like yours is that your particular powder load, with suppression, and your bullet is causing your bolt catch damage through overly energetic cycling. To eliminate the problem, try removing one variable at a time--does your load duplicate others in reloading manuals, if so, then are those loads using suppression and a similar barrel length, etc.

You might also get some answers posting your question on the reloading section or at Castboolits.

 

[Olympus]

I had an issue with the firing pin being a hair too short on an Anderson BCG. Got like strikes ever other round. Replaced the firing pin and that solved the problem.

Anderson has some of the cheapest pricing, but I'm starting to wonder if it's at the expense of quality.

 

[JWH321]

"Anderson has some of the cheapest pricing, but I'm starting to wonder if it's at the expense of quality."

I am having the same concern with some of my recent purchases..kinda worrisome.

 

[Walkalong]

I have used two Anderson lowers and they both work fine. I have not used any of their LPKs.

 

[wally]

Actually the bolt catch is one of the more highly stressed items in a LPK (I'd think only the hammer and firing pin would be higher). I've broken a couple, using heavier than normal buffers and/or recoil springs increases the stress.

But breakages in the early lifetime -- so-called infant mortality failure" -- is a fact of life with modern manufacturing methods. Replace it and keep shooting. "Bending" it back is unlikely to be a real solution, unless you also do some heat treating -- probably where the maker messed up. Id replace this $5 part before doing more expensive things like adjustable gas blocks. If you've got an "extra power" recoil spring, go back to standard.

I have used two Anderson lowers and they both work fine.

Shotgun News recently had an article evaluating ten different stripped lowers against the GI blueprints. Anderson was one of the best, DPMS the worst, but none had any differences that really mattered.

 

[JWH321]

I should explain -- I've had no issues whatsoever with the Anderson produced parts. They are first rate. But they use some parts supplied by third parties which seem to have some quality control issues. While Anderson is not the producer, they are the supplier of these parts. Early parts have been excellent, and my first rifle made up of parts which they supplied has been first rate. With that experience, I ordered a second set of parts -- identical to the first. I have not had the same luck with the second rifle. I found what I considered to be a serious headspace issue. Anderson is trying to make it right, but I am afraid I will have little confidence in the gun until some parts are replaced. It doesn't take a whole lot to spook me with these things, especially with problems in the chamber. The second gun was never fired -- thank heavens for all the folks that preach headspace checks.

Still, Anderson has been responsive and considerate. But my rifle is still up there with no real idea when it will be back.