"seating" the magazine into the lower reciever

[TurboFour]

Just recently finished building my first 6.5 Grendel upper, and when testing feed from the magazines I bought I noticed that if the 5 round mags are full, unless you slam (and i mean really slam, the mag into the reciever to get it to catch. The only way to get the mag into the gun nicely is to lock open the bolt.

Anyone else delt with this problem? I figured maybe the springs need to be worn in more then the 5.56 so I opened the gun, inserted the mag and closed and pused the pin back in. Next day when I got home from work, still couldnt get the mag out via using the mag release button, had to open the gun again. After needing to use a delrin punch and a hammer to get the rear takedown pin out noticed that the first round had a flattened area on the shoulder from pressing against the underside of the carrier.

Sound familuar to anyone? Any advice?

[rasp65]

Turbo Trim off 1/2 a coil from the bottom and see if it fits better trim more if needed. That is what I did with my 5 round mags.

[rkflorey]

Make sure its not a 4 rd mag. Mine will take 5 but then will not seat. I also have a 5 rd mag that works perfectly.

[QuadCam]

trim off a coil or 2 to make it work. check after each spring coil you trim off. my 5 rounder would only take 4 rounds. trimming 1 coil let me load 5 rounds but it wouldn't seat with a closed bolt. trimming 2 coils made it all work perfectly!

[TurboFour]

Make sure its not a 4 rd mag. Mine will take 5 but then will not seat. I also have a 5 rd mag that works perfectly.

I have one "5 round" from Midway USA (AR-Stoner) and another "5 round" from JSE that is a C-Products mag. They both do the same and they both claim to be 5 round mags

[TurboFour]

trim off a coil or 2 to make it work. check after each spring coil you trim off. my 5 rounder would only take 4 rounds. trimming 1 coil let me load 5 rounds but it wouldn't seat with a closed bolt. trimming 2 coils made it all work perfectly!

I can get 5 rounds in, the 5th one is more or less forced in, but not to the point where I wouldnt think it could hold 5 rounds. I will try trimming off some coils as soon as I can figure out the trick to popping the floor plate off the mags. (all my 5.56 mags are pmags)

[rasp65]

I can get 5 rounds in, the 5th one is more or less forced in, but not to the point where I wouldnt think it could hold 5 rounds. I will try trimming off some coils as soon as I can figure out the trick to popping the floor plate off the mags. (all my 5.56 mags are pmags)

Turbo Pry up a little on the tab that is bent down with a screwdriver and slide the floorplate off with your thumb. It doesn't take very much to lift it up.

[TurboFour]

Thank you everyone!! Worked perfectly, cut two rings off the bottom of both 5rnd mags (C-Products and AR-Stoner) and the 5th round went in much nicer and had no trouble getting the mag locked into the mag well.