A while ago I had an issue with a few billet receivers I had. The TD pin wouldn’t lock in, detent not lining up. The company resolved the issue, had a few lightly modified pins sent out at n/c. They just elongated the detent slightly, no biggie. I had 4 pins, 2 would work in all but one receiver, one would work in all of them…
Well, I bought an HVA AMR for one of the builds. It never fit right, mags would just pop out if they were loaded. After inspecting, found the pin/threaded rod portion of the amr was shorter than mil-spec. Both HVA and myself figured that was the issue. HVA was very helpful and sent out the newest version, it has a few upgrades, as well as a longer shaft.
That amr also had issues in one of my forged lowers, so I was sure it was the issue.
I figured issue would be solved, so tonight I finally got around to trying it.
Sure enough, auto-mag release. Mags just drop out if loaded, they even pop out just by shaking the rifle when empty. Only shitty cmmg mags will stay in, but you can pull em out without pressing in the mag release.
The magwell seems to be more open/wide for easy mag insert and release. AND the button hole seems to be machined larger than the forged lowers, combination of both seem to be causing the mag auto dump issue. I can shim the button back, and it holds, or cock the mag in the magwell and it will hold.
I know I have read on a few descriptions for billet lowers that they work with MOST parts.
My question is has anyone had an issue similar to this, where an ambi mag release won’t work in their billet lower?
I have assembled all but one of the lowers. I am thinking about returning the lower to the mfg as I can buy 2 forged lowers for the price of one billet.
I mic’d the measurements for the takedown detent hole, and found the issue with that was the hole was not milled in the correct area, slightly off. That issue is solved, but now this.
I Installed the amr in 3 of the forged lowers I have now and it functions fine in everything but the 2 billet lowers I still have immediate access to. All 4 of the billet lowers hold mags with mil-spec mag parts… For now anyways. Who knows after they get some use.
I will not openly share the mfg’s name till I contact them to see how they want to go about this.