Bolt catch falling behind mag follower & excessive bolt catch play.

T

The_Shmoo

CGN Regular
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Location
Missisauga, ON
Just about finished building my new NEA lower (z series blem, yeah I know...). Only missing the tube, buffer, and stock. The LPK is from ATI.

When I function test with a couple of M2 PMAGs I just picked up, I notice the mags have a slight amount of fore-aft play, and when inserted, any sort of motion causes the bolt catch to fall behind the follower, and prevent the mag from dropping free.

I have noticed as well that the bolt catch itself has a noticeable amount of play. Don't have my feelers at current, so can't say how much, but I'm also new to the AR game so I don't know what is normal or spec.

I'll attempt pics when I'm back at home.
 
Please forgive if the pics are crap, phone camera.

Bolt catch play.
lowerredux2.jpg


Bolt catch behind the follower on GEN M2 PMAG.
lowerredux3.jpg
 
Ya, looks like the slot is too wide and/or the relationship between the magwell and that slot are out OR there is a chance that the ATI bolt stop is out of spec. See if you can borrow someone else's bolt stop and if the problem doesn't disappear, then it's the lower that is the issue.

If it's the lower that's the issue, you could try sending it back, or if you're inclined you could make a steel or brass shim that goes on the back side of the bolt stop that would hold it forward which may or may not fix the problem.
 
Yeah, I might skive off after work to al f's if it's still light, or maybe tomorrow, and pick up a couple of GI mags or LAR's to try and isolate the problem. Otherwise I'll pop the bolt catch out and do some more investigation. I don't suppose there is anywhere in TO where I can just pop in and grab a new one.
 
Not that I can think of. Epps is a little far away......

Do you own a set of calipers? Measure the length of the 'finger' and the thickness of the 'blade' that goes in the slot, and when I get home I'll compare it with one of mine (unless someone else beats me to it). That should give you a better idea of whether the problem is the bolt stop or the lower.
 
Take these numbers with a grain of salt.

I measured from the tip of the finger to the opposite side of the catch, got .438".

The blade of the catch measured to an even .150".

I'll try and get some more numbers tomorrow.
 
While not entirely unexpected, grabbed a couple of CProducts LAR mags, and they fit and function perfectly. Plenty of grab on the finger of the catch.

Guess I'll throw the PMAGs in the plinking pile.
 
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