Compatible AR .308 Lower Parts Kit

I’m working on an AR .308 build. This is my first. I’ve completed a couple of AR-15 lowers and understand the way that everything should work.

I purchased an Aero .308 lower receiver. I now understand that it is a proprietary M5 lower and not all AR-10/.308 lowers are compatible. Things were too easy with the AR-15 platform.

I purchased a CMMG .308 lower parts kit to start my build. In attempting to build the lower, I realized the magazine catch was too short to extend across the lower body and make the magazine release functional. In addition the pivot pin was excessively tight and gritty when inserted in the lower and the bolt catch screw was short enough I was concerned about its functionality (luckily Aero provided one with the lower receiver).

Where can I purchase a magazine catch compatible with the Aero lower? Maybe I should have purchased an Aero M5 lower parts kit. Got sucked in by a good price. Paying for it now.

Was I a fool to use a CMMG lower parts kit? I installed one in an AR-15 build and didn’t have any issues.

Where can I get a great .308 AR or AR-10 lower parts kit when I tackle my next build?

Hi, I know stag has a ar10/.308 lower parts kit . listed as 308 Lower Parts Kit
$98.99 page 2 under there ar10 products ,not sure if its compatible with that AERO lower. Did you try calling the AERO guys to see if their lower has to use one of their parts kits specifically or just a AR!0 specific lower kit. Hope this helps .Ceikberger

Hi again just surfed alittle and found
CMMG, Inc Lower Parts …
Daniel Defense Lower Parts …
DPMS AR15 Complete …

Brownells and Midway both carry kits

Ceikberger, I looked at Aero’s website and saw that they have an extended magazine catch button for their M5 lower. Looks like Aero created this issue and I need to apologize to CMMG for the magazine catch problem. Still concerned with the other parts.

I looked at Daniel Defense a week ago and didn’t see a .308 lower parts kit. I may have missed it. I’ll check again.

Thanks for the help.

There is wisdom in consult.

The Aero LPK built for the M5 is $89.

Always willing to help out a fellow builder after all thats what this forums all about. ,They may have increased the area at the magazine release to be wider and thicker for better support of the release actuator increasing lifespan of the lower after all the magazine well is longer and wider so its possible they wanted it make it more robust because of the larger caliber and exerted forces transmitted through the parts. You may just have to get one of theirs or the DPMS kit to finish the build. Good luck and hope you end up with a tack driver like mine.

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calgunandprep, it looks like I was a fool for getting the CMMG kit based on price and ease of order. I need to get an enhanced magazine catch button from Aero, now. There goes any savings I thought I was going to reap. I have to make my mistakes to learn them.

Thanks for the research.

ceikberger, hope my gun ends up half as cool looking as yours.

Heppy to help! Thank you for sharing the lesson learned.