How do the RRA mag blocks stay in place(pin in or drop in from the top)?
Do they use the same mag release as the 223 mags do?
How do they compare to ASA or other blocks?
Thanks for the info.
Z

The RRA 9mm mag blocks are for the Colt 9mm system only and are real easy to use. the mag block slides into the mag well just like a .223 mag does. In the bottom of the front section is an allen screw that goes straight up into the front block piece and when tightened causes two little pins to come out of either side of the front block section. These round nosed pins lock the mag block in place. You can adjust the correct height of the block to make up for differences in upper/lower combinations. this block allows the use of the standard .223 mag catch. I've never had the ASA type so you'll have to see if somebody replies about it.

ZMan,
The ASA mag block has to be the simplest out there. You just  drop it in from the top of the lower receiver before installing the upper. The AR mag release mechanism secures it in place. It won`t drop out. It is also one of the cheapest blocks out there. I just picked up a complete Rock River today, so I`m going to get to try out both!

ok but can a person reliably use an ASA block with an RRA upper???

BTT cuz I'm wondering too.

Me too.