I have an ar in 6.8rem and have wanted a 9mm carbine for a while. And have decided the most practical right now would be to get a 9mm upper which model 1 appears to be the least expensive.

They sell a mag block shown here http://www.model1sales.com/item-detail.cfm?ID=LRPMWC9&storeid=1&image=9mmagwell.gif&CFID=45886829&CFTOKEN=76435884#

and it it aparently uses these mags by promag http://www.model1sales.com/item-detail.cfm?ID=AMA20RD&storeid=1&image=mag.gif&CFID=45886829&CFTOKEN=76435884 I believe there the ones pictured on the left.

I emailed them to ask what type of mags they are and if I can use anything other than the promags. But I thought you guys may already know.

I would like to easily be able to switch back and froth from 6.8 and 9mm

Link

Anything for the colt pattern.

Hahn dedicated, top load, bottom load, and RRA.  Of course, M1S too.  Just a note on the Hahn top load block, to have BHO you need a 9mm specific bolt catch.

Hahns have issues with promags.  I cant remember what mine was doing but from what I've read its not uncommon.  Also, since the Hahns have a longer feedramp, the front of the follower on CProducts mags need filed down a little so it doesnt get caught on the ramp.

My RRA block would not run with CProducts magazines.  No matter what I tried.  Burned up a case of ammo in a matter of a day or two trying to get it going.

Colt and modifed UZI mags ran great with both, but no BHO.

There is also the VM Hy-Tech block that uses unmodified UZI mags, and only unmodified UZI mags.  I dont have any experience it though.

I currently use the Hahn top load block with CP mags.  I have a few colts and modded UZI mags, but the CPs are what I buy.

Hahn Precision is Top-Notch.  I prefer the top-drop in block.  I like to switch between my 7.5 inch 9mm upper and my 11.5 inch 5.56x45 upper.

All I do is change the top-end, pull out or drop in the mag block and insert the appropriate magazine.

The Hahn mag-block does not need to be adjusted, like the Rock River does, you simply push in the mag. release and drop it in. Close the reciever and you're done.

Best out there.