Okay, this week I got the bolt & carrier joined permanently. It wasn't actually me who did the welding, but I'm not going to name names right now. The bolt was positioned and TIGged in place, and then the valley was filled with the MIG welder.
This is the side view showing the alignment of the pieces. I milled the bottom surface flat after it was built up with weld. It won't hang up on the hammer now.
Here's a little better view of the underside. You can see the hole for the firing pin retainer. The retaining pin can be driven out thanks to an access hole that is drilled all the way through the carrier.
Since these pieces are now permanently attached, 1 part has been eliminated from the total parts count list. Also, this rifle will not be gas operated. That means there will be no gas piston, so another part is dropped from the list.
The carrier may be considered as a U.S. made part since it will not function in the original configuration and has been substantially modified. I won't know unless I submit it to the feds, and that's not going to happen. I will only have 13 countable parts in this build (14 if I make a muzzle brake). At this time, I will have 9 U.S. made parts in the build (if the carrier is counted as a U.S. made part). Only the trunnion and stock set will be imported.
This piece is the prototype. Once I find out if this works, I'm going to make one out of a single piece of steel. I'm going to mill it similar to the Bizon carrier and possibly use a Sten extractor. A Cobray extractor would be another possible contender.