I was lying in bed last night when it occurred to me I might be able to tighten up my old X-Products upper if I dimpled the bottom of the lugs with a center punch. So I started working on it at midnight, AND IT WORKED! I put 3 dimples on each lug, but the first one in the center of each lug was a hair too deep on both of them. Then I put the 4 other dimples on the lugs. It fit my lower so tight I had to pound the pins in with a mallet, and use a punch to knock them back out. Then I spent maybe a half hour with a half-round Swiss-pattern (jeweler's) file, filing down the bumps in the bottom of both holes. I now have a hand-fitted upper, that I previously had no use for, because it was such a sloppy fit. You can see where the 6 dimples are, which I covered with a paint pen.
I chucked a piece of a bolt into a cordless drill, and stuck a used blank case on it. Then I used toothpaste with it to polish the chamber in the nozzle. The Armscor blanks still stick a little bit if I press them in as far as they'll go, but G.I. M200 blanks have a little wiggle room. I used blue Loctite to screw the nozzle into the X-Fore tube that's inside the aluminum free-float tube. Then I screwed the tube on really tight. I put a spare charging handle with an extended latch in, and when I get the other nozzle, I'll be putting it on the forged flattop upper. I just put a prototype 4th slot Hard Charger side cocking handle on the forged upper, to replace the 3rd slot tactical mount that was on it. The carry handle that I cut a space in the bottom of was mounted back 1 slot from where it's supposed to be. The back was hanging over just a little bit, and now the carry handle is mounted in the right place, up to the front of the rail.
I got a text from UPS at 6 am saying to expect my package from X-Products next Tuesday. After I get the new nozzle installed with the Can Cannon in this upper, I'll have one upper with the Can Cannon always mounted, and the other upper with the X-Fore always mounted. Now all I have to do is find my red-dot optic and Picatinny riser to put on it. Then when I switch uppers, all I have to do is swap out the bolt carrier group. I have an extra one so I don't have to take one out of my rifle uppers when I want to use the Can Cannon or X-Fore, and I'll use the same BCG for both of them. When I get these 2 uppers and attached launchers finished, I'll post pics of them.
Since I don't have the quadrant sight on the carry handle anymore, I didn't need the hex nut on it that I used to replace the front knob that was in the way. I decided to put the knob back on, but the threads don't go all the way to back of it. The back of the knobs are counter-bored and there wasn't enough left of the shaft on the carry handle to screw the knob onto. So I threaded a bolt to fit the knob and cut the head off, then chucked it in a drill. I ground the back of the knob off by spinning it perpendicular to the bench grinder until it was just about to the threaded part. It was enough to screw the knob on the previously shortened stud.