What is the prefered 9mm Glock mag conversion block? Shooting my 5.56 pistol has me wanting to build a short 9mm AR as well for range/general shooting.

I know Stern makes a mag block that has good feedback from users, and there is a Torqmag adapter that requires mag modification.

Are there other mag blocks I should look at?

I would prefer a mag block to a dedicated upper. Using a single pistol and/or registered SBR lower for both 5.56 upper, and 9mm seems desirable.

I run a Glock 9mm and have a large stash of mags for it, so I do not wish to pursue a Colt mag style build.

Thank you

Andy