Problem with a new BCM lower

[POB]

Well, we had guys with the tab hitting the bottom of the mag wells and some not and still not working. Makes me want to buy a Gen3 just to see for myself, not that I will do anything about it, just curious.

[81mmcat]

Can't believe this thread is still going, but both my BCMs will lock in the gen 3 mags just fine.

[samuse]

Maybe I'm just missing the obvious but if the mag goes in no problem without the upper on or with an open bolt wouldn't that mean the lower fits the mag and something else is off?

That's not the problem. The magwell where it meets the trigger guard is lower on some BCM lowers, preventing insertion of Gen M3 Pmags in any condition.

FWIW, I quit using my BCM lower altogether and I now actually have a pretty high opinion of the Gen M3 mags. That lower had gremlins....

[Jaysop]

That's not the problem. The magwell where it meets the trigger guard is lower on some BCM lowers, preventing insertion of Gen M3 Pmags in any condition.

FWIW, I quit using my BCM lower altogether and I now actually have a pretty high opinion of the Gen M3 mags. That lower had gremlins....

Ha so I have a different issue. They lock in fine if I rock it back.

[samuse]

Ha so I have a different issue. They lock in fine if I rock it back.

Split the lower and the upper. Slide the mag in holding it rocked to the rear and see if it locks in. If it hits and prevents locking, you have very marginal clearance and the mag will likely bounce out if you try to top the gun off with the bolt forward.

[Jaysop]

Split the lower and the upper. Slide the mag in holding it rocked to the rear and see if it locks in. If it hits and prevents locking, you have very marginal clearance and the mag will likely bounce out if you try to top the gun off with the bolt forward.

Works perfect without an upper on it. Also locks in just fine they are half loaded. Only issue is when it's fully loaded (30 rounds)

[samuse]

Works perfect without an upper on it. Also locks in just fine they are half loaded. Only issue is when it's fully loaded (30 rounds)

With the bolt forward?

When you try to load it and it doesn't seat, pull the mag out and look at the top two rounds to see if the second round has wedged itself up toward the first round.

[7.62NATO]

Have (or maybe had...) a BCM lower that regularly refuses to take a loaded M3 on a closed bolt. Sometimes the second round is wedged upward after the failed attempt. Had a chance to try a tac-reload using the same mag in other lowers - with the same upper - and no problems. Other lowers include LMT, Colt, KAC, S&W, PSA. I wish BCM would chime in on this.

[Jaysop]

With the bolt forward?

When you try to load it and it doesn't seat, pull the mag out and look at the top two rounds to see if the second round has wedged itself up toward the first round.

Yes bolt forward.
The rounds don't shift most of the time, only when I try to load it fast. It will never lock it doing it fast only slow and deliberate. The rounds just get pushed down about a 1/4 inch.

[samuse]

Have (or maybe had...) a BCM lower that regularly refuses to take a loaded M3 on a closed bolt. Sometimes the second round is wedged upward after the failed attempt. Had a chance to try a tac-reload using the same mag in other lowers - with the same upper - and no problems. Other lowers include LMT, Colt, KAC, S&W, PSA. I wish BCM would chime in on this.

Yes bolt forward.
The rounds don't shift most of the time, only when I try to load it fast. It will never lock it doing it fast only slow and deliberate. The rounds just get pushed down about a 1/4 inch.

Man that's exactly how a crossed up 2nd and 1st round acts.

I'm out of ideas. All I know is that g.i. mags don't do that.

I use Pmags mostly, but everything has it's advantages a disadvantages...