AR-15 upper/lower question

[Deserthunter]

I believe the answer is yes, but I want to confirm whether a .223/5.56 AR-15 upper will work on a 7.62 x 39 AR-15 lower. I understand a 7.62 x 39 AR-15 upper will work with a .223/5.56 AR-15 lower,, but I want to know if the reverse of that configuration works also. Thanks.

 

[Varminterror]

Same same. There is no cartridge assignment in the lower, it’s just an arbitrary marking.

 

[H&R Glock]

Yes, mine is a homebuilt AR15 lower mated to a 7.62 upper. The 5.56 magazines will hold and feed a few 7.62's but it's better to get an AR-7.62 magazine that has the proper curvature to feed.the bigger ammo.

 

[badkarmamib]

Unless it is something like the CMMG Mutant or PSA KS-47, which are AR lowers designed to use AK mags.

 

[FL-NC]

Unless it is something like the CMMG Mutant or PSA KS-47, which are AR lowers designed to use AK mags.

What this guy said.

 

[herrwalther]

Sure will. Many stripped or complete lowers will say MULTI somewhere on the magazine well to denote it can be used with many different caliber uppers. The obvious exceptions are for very different rounds like a 9mm lower that uses Glock magazines for example.