10-20-2019, 11:35 PM
Well, I went ahead and ordered that selection of stainless shim stock . $50, but I seriously doubt I will ever run out.
As close as I could tell, there was between 5 & 6 thousandth play between the upper and the barrel extension. So I used .003 shim stock. After a bit of trimming to get it the correct length, and to fit around the index pin, it was a very stiff hand push fit for the first 1/8-1/4".
So I very lightly greased the extension, then wrapped the shim stock around it, and greased that, and put it into the freezer. Greased the threads and the inside of the receiver, and put it in the toaster oven at 275. After 45 minutes, they slid together relatively well. Ended up having to use a plastic mallet to finish seating them together. I think the two parts were sharing heat at that point, so the fit got real tight real fast. The biggest PITA was keeping the frost wiped off of the barrel so that there wouldn't be moisture stuck in the mating surface.
I need to find some barrel shims, since the place holder handguard nut I am using for the time being will not time correctly either bare or with the one shim that I currently have.
As close as I could tell, there was between 5 & 6 thousandth play between the upper and the barrel extension. So I used .003 shim stock. After a bit of trimming to get it the correct length, and to fit around the index pin, it was a very stiff hand push fit for the first 1/8-1/4".
So I very lightly greased the extension, then wrapped the shim stock around it, and greased that, and put it into the freezer. Greased the threads and the inside of the receiver, and put it in the toaster oven at 275. After 45 minutes, they slid together relatively well. Ended up having to use a plastic mallet to finish seating them together. I think the two parts were sharing heat at that point, so the fit got real tight real fast. The biggest PITA was keeping the frost wiped off of the barrel so that there wouldn't be moisture stuck in the mating surface.
I need to find some barrel shims, since the place holder handguard nut I am using for the time being will not time correctly either bare or with the one shim that I currently have.