OK, I cut the barrel down 5". Following Larry Potterfield's video, I went looking for a hardened dovetail guide, but the one he used is no longer made. I found one from Dixie Gun Works, but it turns out it is not really square on the ends, not much of a help to make a square cut. That's OK; I do cut dovetails now and then. So, I did my best (not bad) with hacksaw and file. I bought Brownell's 11 degree crown cutter and a "303" brass bore guide. Two reviews on their site: one says "perfect for Mosin", the other "too big". I'll go with too big, but a little emery cloth and a drill press fixed that. Brownell's also sells a handle, but it's aluminum. I simply tightened two 1/4-20 nuts on their threads and used a small ratchet drive to rotate the tool. Tested it before I cut the barrel, and I found that I had to reduce the pilot diameter a little more after cutting. Lands were more worn near the muzzle. The crown tool worked great. Finished with some emery cloth by hand. See my photo.
Got to the range today, and first thing I found is my POI is a foot higher than before cutting. I'll have to adjust the scope mount. I did shoot one group with a warm barrel and not taking my time really. See the photo. I should have checked the spotting scope each shot, but I didn't, so I don't know the order. I would like to think the 3 are my group, and the other two to the right are the barrel getting hot, but I am going to rework my loads first.
Velocity - here are the before/after results:
150 Sierra ProHunter (0.311) 52 gr H380
2,760/2,659 Std 7.0/18.5
Wolf commercial 180
2,619/2,552 Std 53/11.4
Haven't done a thing with the stock. I'm off to rework some loads.