Since critical items for my rifle project are on long back-order, I decided to do something about my MAC-11. I wanted to reduce its rate of fire to something sane, and though a pocket SMG is an attractive idea, in practice shooting it is more akin to holding a rabid weasel than anything else. I decided I was willing to give up pocket-ability in favor of something more SMG-sized and easier to control.
So far, I've ordered one Suomi stick mag and one drum, and a Lichtenberg magwell adapter. The upper is 1-1/8 square, but it turns out that's not a standard size of steel tubing. Oddly, the original upper looks to have been bent in a brake and welded on the bottom, which is how I'm going to have to do it.
Rather than messing with the trigger group I think I'll just make a new bolt with a rearward extension to pick up the original sear. This will also let me move the ejection port from the right to the left. Being sprayed in the face with hot brass is tiresome after a while.
I'm still looking for an inexpensive barrel already chambered in 9mm. Looks like Suomi barrels are either out of stock or $50ish now.