It's gonna look a lot like the .22, just slightly wider and longer in the receiver. Obvisouly, a 9mm blowback bolt needs to be a good bit heavier, too. Like 16 ounces vs. the 6 ounces of the .22 bolt. And of course the barrel is bigger, so I expect it to come in between 3.5 and 3.7 lbs (for those who don't recall the specs or never saw the thread, the .22 pack rifle is 2 lbs 6.1 ounces). The most notable visual difference will probably be the angle of the mag well, which I'm going to carry to the exterior profile. It will use Beretta 92 magazines, and the catch will be external on the front, sort of a shoe, if you will, although I haven't yet decided if operation will be pushing forward or if it will be a lever that presses back against the mag well. Anyway, this is basically the receiver design (red denotes bolt bore, blue for magazine well): Decided to start last night, so I lobbed off an 8-1/2 chunk of some 1.5"x 3.2" 7075-T6 I had and squared it up. Being a deeper and larger bore (1.000" x 6.700"), I wasn't able to use my preferred vertical boring and reaming configuration. I had to ponder how I wanted to attack that for a little bit, and then decided on my 90° milling head. I don't use it very often, but when I need it, I need it! I hate unbolting and removing that heavy Troyke rotary table (208 lbs), so we just used it! I also had to make a shank extension for my 15/16 S&D twist drill to get my 6.700" depth. It was slow going with the short flutes, pecking .200" at a time, but we got it! Then is was on to reaming with the 1" carbide tipped reamer I actually had on hand And after a long evening, we had a block with a hole! I had a bit more time to mess with it today, so I began profiling the front of the receiver and made the ejection port and charging handle cuts. Will probably do more later tonight, but gotta go shopping and need to spend some time with the kiddo. A long way to go, and I have lots going on right now, so I don't know how rapid the progress will be, but I'd like to have it done by Chrismas. The 1" 8620 stock for the bolt showed up yesterday, and the 9mm barrel liner and carbon fiber tubes are en route. Shouldn't need to order anything else, just got lots of cutting to do! Stay tuned!