M3 mag modification

[Petroleum 1]

I bought these used mags last year for my stemple 76/45 is it normal to cut down the feed lip like this?? They sure do run great in my stemple. The new GG mags dont work at all the round will nose dive and jam every other round. Tia Vinny

Edited March 9, 2018 by Petroleum 1

[johnsonlmg41]

In this particular case you'd be better off sending the gun back and having it fixed to take the GG mags unmodified. Mods for the early version were for the magazine catch, not for the feed lips. Not that modifying these mags is a big deal since they are not scarce, but the gun would hold better value if it were fixed to run with unmodified mags. HTH

[Petroleum 1]

In this particular case you'd be better off sending the gun back and having it fixed to take the GG mags unmodified. Mods for the early version were for the magazine catch, not for the feed lips. Not that modifying these mags is a big deal since they are not scarce, but the gun would hold better value if it were fixed to run with unmodified mags. HTH

I agree my gun is supposed to run with unmodufied M3 mags. The magwell is beefed up and a different style mag latch installed which works great. I could be just dealing with crappy used magazines. I just bought some new keep shooting M3 magazines and will try them with the factory feed lips and see how they work.

[johnsonlmg41]

while it's possible you got some beat up mags, the reality is those guns have a pretty bad reputation and were in many cases not put together very consistently depending on the vintage of your build. Of course today as values have rocketed up and the guns are not that hard to fix, it's now worth it to invest some money to make it a real nice and dependable shooter. Back in the day when you had a $400 M11 that didn't run, you set it aside since it was not worth fixing, today spending $1500 on an upper and better parts is common and a decent investment relative to the current value of a working MG.

 

Friends laugh at me when I show them a $5000 piece of muffler pipe with a couple slots hacked in the side. They can't comprehend how this will be a $14K gun in a couple days.

[lonniejt]

This might or might not help. I think the same thing could be accomplished by just bending the feed lips to allow the cartridge to set two or three degree's upward. Look when the mag is inserted and if level, sometimes the bolt will just jam it downward missing the firing chamber. I have both Stemples and Grease Guns. I solved the Stemple issue by having some "feed lips" installed; it will now eat everything. However, for my Grease Gun, I started looking at how the cartridge sets when the magazine is seated and started bending magazine lips for obvious reasons. Just a thought.

[Petroleum 1]

Lonniejt...could you post a pic of the feed ramp you installed? ty I borrowed a couple of standard M3 mags with full feed lips and I tried them the other day they ran fine so I'm thinking I had some weak mags. I get what you are saying about the angle. The stemple ammo has a long distance to travel into the barrel entrance so the round has to have a little "up" angle to get it moving in the right direction or it will nose dive. Opening up the feed lips a little would probably do it. When I get the new mags in this week I will test them with some snap caps then head to the range.

Edited March 14, 2018 by Petroleum 1