308AR bolt ears jammed up against bolt catch

[RacerX]

I'm testing a new 308AR build - testing firing, ejection and bolt hold open.
I would load 2-5 rounds per magazine to test this.
Everything seemed fine until the last round in one of the magazines.
The bolt has jammed up against the bolt catch.
I wonder if there's something in particular I should look at, or if this is one of those "keep firing to break it in" situations.
Also - should I use a punch and a hammer to push the bolt backward, or is there a better way to free this up?

Waterboarding info:

1.) Do you have Armalite AR10 Recoil System:
No

2.) buffer weight
3.79oz (107.6g)

3.) buffer length
~2-5/8" (2-19/32" actual)

4.) Extension Buffer Tube internal Depth
7"

5.) What Spring, Length, Coils, Brand, Color
Brand: 80% Arms (part of their 308 LPK, actual manufacturer unknown)
Length: 11-1/2"
Coils: 28 or 29

6.) Gas System Length- Rifle, Midlength, Carbine, Pistol, Other?
Rifle length

7.) Gas tube Length
~14-1/4" + portion inside gas block (Aero complete upper, haven't disassembled)

8.) Photo looking directly into the magwell

9.) Photo of the Bolt Face
Photo not taken yet, as bolt is still stuck.

10.) BCG Clearance at the ears and bolt stop
Measurement not taken yet as bolt is stuck

11.)  Gas Journal Diam and gas Port Diam
Measurement not taken yet.  This is an 18" Aero M5 upper, I will search to see if someone else has already posted that information in another thread.

12.) Photo and Description of the Malfunction or Issue
As described above, the bolt is stuck against the bolt catch.

 

13.) More Photos

14.) Additional Information
Upper: Aero M5 18" .308 CMV Complete Upper Receiver w/ ATLAS R-ONE Handguard
Lower: 80% Arms
BCG: Aero 308/7.62 with 9310 bolt, black nitride
Ammo: 180 grain Remington Core-Lokt

Edited August 29, 2021 by RacerX
Fixed a typo.

[98Z5V]

What bolt catch is that?  There's no mag in there, but even if there was, that bolt catch won't reach the magazine.  What's pushing that bolt catch up right now?

Edited August 29, 2021 by 98Z5V

[RacerX]

1 hour ago, 98Z5V said:

What bolt catch is that?

It is from 80 Percent Arms.  I'm not sure if they make it themselves or if someone else does.  
I have several LPKs from them, so I dug a few more out, and they were all identical.
The only identifying mark on it is a triangle in a circle:

There's no mag in there, but even if there was, that bolt catch won't reach the magazine.

Here is a photo with the magazine inserted.  It worked fine for 3 or 4 bolt-hold-open tests.

What's pushing that bolt catch up right now?

It's hard to tell in the photo, so I tried to outline where a corner/edge of the bolt catch and the bolt are jammed together.

 

[98Z5V]

1 minute ago, RacerX said:

 

 

There's no mag in there, but even if there was, that bolt catch won't reach the magazine.

Here is a photo with the magazine inserted.  It worked fine for 3 or 4 bolt-hold-open tests.

 

What's pushing that bolt catch up right now?

It's hard to tell in the photo, so I tried to outline where a corner/edge of the bolt catch and the bolt are jammed together.

 

What on that bolt catch actually touches the magazine?  That finger that sticks out of the middle of the bolt catch is what's supposed to do it, in the center of the magazine.

[RacerX]

I also have an LPK from CMMG, so I decided to compare the bolt catch between the two kits.

Some of the dimensions are different, but I believe the "ear and the tooth" (sorry, I don't know what proper term might be) are still in the correct location.
Mostly it appears to be less beefy.
I can dig out my calipers and take some dimensional measurements, if you like.

 

[RacerX]

3 minutes ago, 98Z5V said:

What on that bolt catch actually touches the magazine?  That finger that sticks out of the middle of the bolt catch is what's supposed to do it, in the center of the magazine.

Yeah, I was hoping you could see in the photo - it does stick out there.

The green of the magazine is almost the same color as the gun, so it may look like the magwell to you.

Edited August 29, 2021 by RacerX

[RacerX]

9 minutes ago, RacerX said:

Yeah, I was hoping you could see in the photo - it does stick out there.

The green of the magazine is almost the same color as the gun, so it may look like the magwell to you.

I put a little piece of paper on the magazine so you could hopefully see it better.

 

[98Z5V]

That's an AR15 bolt catch.

[DustBuster]

I tried ordering myself a 308 specific bolt catch, and when it came it was almost smaller than my original LPK catch.  Still haven’t found a good huge beefy one.    Maybe to get the thing unstuck you can immobilize the receiver, put some tension on the charge handle, and tap downward at the correct angle upon the bolt catch with your punch there.  Then investigate more on a different catch

Edited August 29, 2021 by DustBuster

[edgecrusher]

15 minutes ago, DustBuster said:

I tried ordering myself a 308 specific bolt catch, and when it came it was almost smaller than my original LPK catch.  Still haven’t found a good huge beefy one.    Maybe to get the thing unstuck you can immobilize the receiver, put some tension on the charge handle, and tap downward at the correct angle upon the bolt catch with your punch there.  Then investigate more on a different catch

Armalite

[jtallen83]

1 hour ago, RacerX said:

I decided to compare the bolt catch between the two kits.

Here are a bunch to compare to;

 

Amazing how many different variations there are as well as all the different parts vital to function it interacts with, add those numbers if they aren't there 

[shooterrex]

If that is a threaded bolt catch pin just remove the pin and take the bolt catch out. Watch out for spring loaded parts flying.

[RacerX]

55 minutes ago, jtallen83 said:

Amazing how many different variations there are as well as all the different parts vital to function it interacts with, add those numbers if they aren't there 

It is amazing, and thank you for providing me that link.
I took the time to compare AR-15, 80% 308 and CMMG 308 catches and dimensions B, C and D are different, with D being most interesting as the 80 Percent pin height (D) is higher than both of the other two catches.

[DustBuster]

55 minutes ago, shooterrex said:

If that is a threaded bolt catch pin just remove the pin and take the bolt catch out. Watch out for spring loaded parts flying.

This is a great idea to try first.  In any event, the bolt catch is way more expendable than the bolt, even if you had to dremel the catch out somehow.

Ive had my bolt “catch” prematurely on the bolt catch before, getting stopped in that position of your bolt, Racer X.  Mine got stopped in that position because it was being lifted up Too High and as the bolt traveled rearward with the charging handle, it hung up.  I fixed it by reducing the follower lift, of magazine.  I discovered my problem before I ever fired a shot.  Possibly a different problem unique to my setup.    I have been trying to find a wider bolt catch for use with a different bolt I have which has smaller lugs.. wanting a bit more surface area at the stopping point.  Good luck.  Maybe you could just take the charging handle and give it a fast forceful snap backward if the other methods fail to get er Unstuck.