receiver trigger hole metal thickness specs?

[Bluto]

I'm trying to find out how thick the metal needs to be on the bottom of a lower receiver where the trigger comes through. Not the dimensions of the hole, just the thickness of the metal.

[GH41]

I'm trying to find out how thick the metal needs to be on the bottom of a lower receiver where the trigger comes through. Not the dimensions of the hole, just the thickness of the metal.

Not sure I have ever seen that dimension noted. It's pretty much what you have left after machining the trigger pocket to the correct depth. A lot depends how the forging was fixtured. That is why you rarely see both sides of the pocket equal thicknesses.

[lysander]

About 1/16 inch, give or take a 64th or 2 . . .

[Kadelic]

Did a quick caliper check on my BCM lower. It measures 1.338" from the top of the lower to the bottom of the lower, and 1.25" from the top the the bottom of the trigger pocket. So .088", sample of one.

ETA: fixed typo

[Steve Shannon]

If you don’t mind using HK metric dimensions, here are snips from a drawing in the HK416 TDP.
https://uploads.tapatalk-cdn.com/20201111/b915c1057efc6de90f8794d6c822fb62.jpg
https://uploads.tapatalk-cdn.com/20201111/a53927b8becb7bdc7013e4805b3c2b90.jpg

[Bluto]

Here's why I'm asking...

Check out this thread: https://www.m4carbine.net/showthread.php?223531-Misspelled-trust-name

I received the lowers back and the engraver ended up grinding the engraving off of the trigger area, refinished the receivers and engraved the trust info in the magwell instead of the trigger area.

My main concern is why engrave the magwell? I'm thinking because he removed so much material there was not enough left to engrave into.

I don't have calipers fine enough to measure through the trigger hole so I dug out another lower from the same manufacturer and production batch to compare. Measuring from the top of the receiver to the front of the trigger hole the "good" receiver measures 33.95mm. The repaired one measures 33.09mm, a difference of .86mm. Not a tremendous amount, but do you all think it's good to go measurement-wise?

Also, I'm certain the grinding heated up the metal. Should I be concerned about metal fatigue?

These are not big differences and I'm probably over-thinking it so I figured some of you much smarter gents could either tell me I should throw away the receivers or that I'm complaining like a sissy.

And yes, I've flamed the engraver mercilessly.


ETA: these are PWS lowers, if that matters.

[Steve Shannon]

I think you’ll be just fine. Fatigue doesn’t happen due to heat from grinding and it’s not a critical area.