MAX-11/15a1 swap to 7.62×39? Safe with IRM?

[A&S Conversions]

Since you have both the M11/15 and the M11a1/15 which would you recommend if someone (like me) has both an M11/9 and M11a1, but con only get the 556 upper for one of them?

This goes back to the original Max 15 discussion about whether to get the AR receiver extension, buffer, and spring with a hole in the back of the M11/NINE receiver or the internal recoil spring system that does not require a hole in the receiver. If you are interested in configurations and calibers other than factory standard then the M11/NINE would have more options because it uses standard AR carriers. If you want the factory configuration, then the M11A1 would be more compact keeping the mass that the firearm closer to the body, which all things being equal, would tend to be more controllable.

Scott