Thinking about building a 9mm AR,

but I don't want to have to buy special magazines or any brand specific parts.

So while searching, I came across the following thread on ARF.com:

Olympic Arms 9mm bolt question

I'll post links to the videos that the gentleman made below;

Link 1

Link 2

Link 3

Link 4

Link 5

So despite what MANY have told me, the AR-15 magwell is evidently NOT to narrow.  I have been trying to find a magblock adapter that will allow me to us Glock mags, and I'd LIKE to make a 9mm and a .45 ACP upper.  It's not necessary to use the standard AR mag release, infact if there was just a button at the front of the magwell that has to be pushed up, that would be better in my opinion.  Keep the standard AR mag release for removing the mag adapter from the magwell.

If a machinist wanted to make something like that, I would pay for and build the necessary uppers and test the heck out of it for them.  and after all the bugs are worked out, I'd like two of them for myself.  So I could have a carbine in 9mm and another in .45 ACP.

It DOES work and it HAS been done.  So the biggest issue now is remaking it with a different mag release and retention.