7.62 FGMM 175 & Magpul 10rd. mags.

[BigOhio]

I just picked up a couple of the new 10rd Magpul mags and was very disappointed on my first trip to the range with all kinds of feeding problems with 7.62 FGMM 175s. Upon examining the mags it seems as the rounds are placed in them, the mag bulges and bullet hangs up on the front of the mag. I have never had issues with the 20rd. version so headed home scratching my head and thinking not so good thoughts about the new mags. Well I get home and measure the 7.62 FGMM and find they are about 2.815" in length. I then pulled out a few of the 308 version of the FGMM 175s and find they are right at 2.800" and seem to feed fine through the mag. Did a few searches and found a few threads discussing the OAL difference so feel this is how they are suppose to be.

My issue is that I have a good supply of the 7.62 version of FGMM but not so many of the 308 so my question is does anyone know if I could just run the 7.62 version through the seating die to a length of 2.800" and call it good or are there other issues I should be aware of such as sealant, etc. Also, from prior experience, I know the 7.62 are a little hotter than the 308 but think seating the bullet down a little would decrease the pressure if anything. Anyone ever do this or have any comments?

 

[hlee]

Assuming the 175s are not jammed into the lands when chambered, seating the bullets deeper into the cartridge will increase the pressure of the round- as you are effectively decreasing the volume of the cartridge. Will 0.015" negatively effect safety or performance? I do not know the answer to that. If it were me-and I were to try to seat the bullets deeper- I would go in small increments and relatively small "batches" looking for pressure signs along the way.

 

[BCP]

If the 20rd ones work I'd call Magpul up it's possible that those 10rders are defective.

 

[ORD]

All of the LR/SR GEN M3 mags regardless of capacity should be able to reliably accommodate anything less than 2.820". If your mags won't...get with Magpul and see what they have to say and what, if anything, they can do to assist you (including asking them whether they somehow changed the specs for the 10 LR/SR GEN M3 versus the 20 LR/SR GEN M3 which should be identical save the number of rounds per mag).

Magpul CS is generally very knowledgable and easy to deal with in my experience. Just be thorough in your comms with them, including something akin to your description of your problems as listed above.

 

[Pilky01]

I contacted Magpul about a missing dust cover in one of my sealed 10rd lr/sr mags. The rep was a total prick. I was pretty disappointed.

 

[Desert_Racer]

I contacted Magpul about a missing dust cover in one of my sealed 10rd lr/sr mags. The rep was a total prick. I was pretty disappointed.

I didn't know anyone even used those things... I usually throw them in the garbage, but that's just me.

 

[redirt78]

If you don't get the answers you're looking for about the 10 rounders just run that ammo in the 20s, I wouldn't press the bullet into the case but that's just me. Good luck either way

 

[Pilky01]

I didn't know anyone even used those things... I usually throw them in the garbage, but that's just me.

One mans trash is another mans treasure. I live in the salt flat desert of western Utah. The dust here can be a real pain in the balls. I have found that those cheesy dust covers can save me some serious cleaning time.

 

[pmclaine]

The dust covers also push the loaded rounds down into the mag taking pressure off the feed lips.

I dont know but if simply loading 175 FGMM into the mag distorts the body it may be a good idea to not stress the feed lips if using the mags to store ammo for any amount of time.

 

[BigOhio]

Thanks for the responses and decided not to resize the FGMM ammo and just use the 20rd. mags until I can find a solution to the 10rd. mags. I have an email into Magpul and they requested the OAL of the ammo so hopefully they are working on it. Also, for what it is worth, when squeezing the mags at the top by the feed lips, the 10rd mags seem more flexible than the 20rd mags.

 

[77Bronc]

After reading this post I got curious about some new Gen 3 10 and 20 round mash I ordered. Since my LMT MWS really likes 7.62 175 grain FGMM ammo, I loaded each of the mags. And while the OAL of the bullets appears tight, they do fit into the mags with no apparent bulging or distorting.

I will say the 175 FGMMs do fit better in some original PMags that I cut down to 10 rounds. If that makes any sense.

77