Hello Pro’s.
I peruse and absorb your knowledge quite often but have yet to post in this forum.
My GAP10 Bolt Catch has snapped. I’ve owned many ARs but this is my first 308 Frame AR and I don’t know if the bolt catch is a generic AR part or does the larger AR10 frame require different small parts?

Attached File

I have a Gap10 (for sale in EE) this happened with. Following a phone call to manufacturer, a replacement was sent out. Free iirc. NBD

Thanks for the info. I called and then eventually emailed and there was no offer to replace.
They just informed me they don’t sell small parts. I also didn’t ask the question of parts interchangeably so my bad.

I had assumed I banged it on a concrete bench or something as I didn’t notice when it happened. I’m surprised to know you had the same problem.
I can’t imagine any inherent flaw in the GAP10. Maybe we both bumped it into something?

They’re pretty good people there and I don’t expect a lifetime warranty so if I can just find the correct fitment I’m only out about $15.

I appreciate your response though.

Mine broke when shooting suppressed. I got the feeling back then this breakage was common when shooting suppressed.

Nailed it, I guess?

I shoot suppressed 99% of the time. It’s a shame, less than 500 rounds through it as well.
I came down with Parkinson’s Disease and even a 4K setup is useless to hold a group anymore.

I still won’t part with my toys though as they are most of the best memories of my life. I would really like to fix it as that’s one of the few things I’m worth a damn for anymore.

So I now have three questions:

Can anybody verify small parts interchangeably (Bolt Catch size)?
Does anyone have any knowledge of a problem with GAP10 ‘suppressed’ failures of the bolt catch?
Is there a general consensus on an upgrade for strength as most prices range with cosmetics.

The lower parts may be available from Seekins Precision. I looked but did not see it on their site. Try calling their customer support. Seekins & GAP were working together on these rifles at some point.

For shooting suppressed, an adjustable gas block needs to be calibrated correctly. Don't think I got 50 rounds out of my bolt catch after mounting the suppressor (I did not calibrate the GB). Lesson learned.

Good luck.

I used a DPMS ar 308 bolt catch.  I'd read that other catches wouldn't catch the bolt 100% of the time.  You should have no compatibility issues.

I'm going to guess that your buffer allows too much travel.  This increases the amount of kinetic energy imparted to the bolt catch.

With the bcg held all the way to the nearby the charging handle, there shouldn't be more than a 1/16" between the bolt face and bolt catch.  Check this measurement first before Looking elsewhere.

Great advice from everyone.

Since I sent my suppressor to GAP for tuning prior to them shipping  my rifle for final transfer
and it worked......
I assumed all was well.

I’ll check the measurement and grab a DPMS catch if all is well.

Then I will go read up on tuning my adjustable gas block.

Thanks again!

I've seen several broken bolt hold open devices on AR10s and DPMS .308s when shooting suppressed.

I think KAC had the problem early-on when they started shooting suppressed with the SR25s, and addressed it with metallurgy.

I've seen it on suppressed ArmaLite AR10s that didn't have any way to mitigate the suppressed use, which is why ArmaLite built the SASS with a really nice adjustable gas system.

With the M4 TDP, the small parts have very tight controls from materials, processes, inspections, and tests, to include MPI for the hammer, trigger, disconnector, bolt catch, and selector.

The problem is the bolt carrier and bolt mass in the large frame guns, slamming into the bolt hold open device on last round.

Especially when you shoot more 5rd strings from the mag, you increase the frequency of impact on the part, and increase the carrier velocity when you shoot suppressed.  When the buffer bottoms out in the RET as it's supposed to, the increased velocity from back-pressure induced cyclic rate increases contribute to faster forward carrier speed as it goes back into battery or towards bolt hold open.

Since the AR15 has a much lighter BCG, you just don't see this with AR15s.

Also makes sense.
I’ve used a Bob Sled for 99% of my shooting. I’m now curious if the Bob Sled would have any positive or negative effect.

- Here's How It Works - The Original Bob Sled (OBS) is inserted instead of a magazine. When the bolt is opened, the built-in plunger trips the bolt catch and holds the bolt open. A single round is then placed in the ejection port and allowed to rest in the channel of the OBS. The bolt release button is pressed and the single round is loaded. When that round is fired, the action cycles normally and the OBS plunger trips the bolt catch lever to hold the bolt open. This provides a very smooth operation for the slow fire that is required during High Power Rifle Competition, Benchrest Competition, load development, and varmint or long range shooting where the length of the bullet may exceed maximum magazine length.

Since this seems it may be a prone to failure component of the AR10, what brand of bolt catch has the best metallurgy? Or since that’s probably hard to define, does anybody recommend a specific manufacturer?

As I posted earlier, DPMS.  They seem to have the fewest failures than any other.  Whether that's metallurgical or design, I don't know.

Bolt catch breakage, as stated by others, has been rather common.

and again, Thank You for your advice.
(2) on order so my midlife crisis is over