Colt 9mm two piece mag block?

I recently purchased a Colt 9mm sub machine gun parts kit from Ratworx. It came with with everything except the sear, selector ,which I had held out, and of course the lower. I already have a pistol lower that I was planning using. So I ordered a kak mag block.

I installed the mag block but can not get it to hold a mag. The problem is that the mag block moves up when putting the mag in. Especially when the mag is loaded. The mag block has two set screws that should hold everything in place. I even tried drilling two indents in the lower to try to hold it in place with no luck. I'm not trying to trash kak and I have not taken the time to contact them.

So I was thinking about using the two piece Colt mag block that came with the parts kit. Considering that lower receiver prices are at an all time low price and that I can not find a dedicated lower. So the question is does anyone know of a source for a template or a way to make a template to drill the holes? Or a shop that can do the work without totally screwing it up?

You need to drill two holes through the receiver and the block to make it stay. Or you can do what I did and jbweld the kak block into the receiver.

I’ve thought of drilling and pinning the Kak block in place. But if I’m going to drill holes in my receiver I might as well just use the colt two piece mag block.

I agree if you have the colt conversion block just pin it.

Just curious if you ever resolved this issue and used the two piece Colt mag block ? I too have a Colt 9mm SMG parts kit and would like to know if anyone could recommend a good gunsmith to install this block in a dedicated lower ?

I have not yet installed the Colt two piece mag block. I bought a three pack of the Mean Arms magpul conversion. Long story short they didn’t work but they did replace them I have not tried the replacements yet.

Based on my experience I thinking that the best route to take would be a dedicated lower or installing the mag blocks.