I have read the many posts on the site. Thanks for all the info to date. I want to put together a 9mm carbine (RRA A4 Upper). I need a 9mm Colt style mag well block that has the BOLT HOLD OPEN FEATURE I will change my bolt catch and use the lower for 9mm only.

Ideas

1. Buy a two piece COLT orginal and drill my receiver (hope for the best hole alignment)

2. Try and find a new style one peice Colt drop in (J&T is forever out of stock Can't seem to find one anywhere?)

3. Find some other brand that is in stock today ( NEED SOME HELP Here :) )

Thanks for the input

Brad

Hahn Precision from Brownells.

Top load requires a 9mm bolt catch.
Bottom load has an actuator built-in and uses a 5.56 bolt catch.

I second the Hanh

Try RRA block, one piece, colt style, bottom load.
www.adcofirearms.com/rockriver/rra9mm.cfm?page=rra

www.rockriverarms.com/catalog-list.cfm?Category=03&Subcat=9mm%20Parts&storeid=1

www.eaglefirearms.net/rra_9mm_uppers_parts.htm

www.rbprecision.com/rock_river_arms_ar15_rifles.htm


I'm sure others carry them...

Garrison Manufacturing Inc.
www.garrisonmfginc.com
P.O. Box 231
Wauseon, OH 43567
1-419-392-2542

The 2 blocks I have are Garrison. Top loaders, bolt hold open slot. I use colt mags and pro-mags.
Just pop in a 9mm hammer, drop in block, start shooting. You dont need to use a bolt catch if you dont want. I have broken 2 bolt catches so I dont even bother any more. If you dont use a 9mm bolt catch with the top loading block, you can pop out the block and snap on a 5.56 upper. That simple to change cal.