I'm ordering a RRA 9mm upper and was wondering which mag block I should get. I've seen reference to(mainly on this sight)  Hahn's, ASA ( American Spirit Arms, I assume), & Sherluck (maybe?), but really don't know much (anything) about any of them.

I want something that will definitely feed h/p's as well as ball ammo. Also one that has the hold open feature for the bolt.

The thing I'm not sure about is quality, and the different mags that each mag block uses. I know there are some that use Uzi mags, Sten mags, modified and unmodified. I think I would rather have a block will accept Colt mags, just because they are probably a little better quality magazine than the others.

Also, is there any benefit to having a block that drops in from the top, other than it not falling out of the bottom (I seem to like that idea, though) as opposed to ones that go in from the bottom?

Any and all suggestions are more than welcome, and don't worry about offending me...I'm a self-admitted newb when it comes to the 9mm AR (although, I am aware of the hammer and buffer replacement).

Thanks guys.

You'd get an answer much faster here Rimfire and Pistol Calibers Forum

Thanks, duely noted....And already found my answer. I appreciate it.

When using the ASA model, you just drop it in from the top, no holes to have drilled, no allen screws to lock down.Just close the receiver and the friction does the rest.You even use the standard mag release.No bolt hod open though.