Back in April I e-filed a Form 1 to turn my TNW Firearms M-31SA Suomi into a short barreled rifle. BATFE approved the Form 1 on July 19th, but never emailed it to me. I logged into atfonline.gov last week, and lo and behold, it was sitting there in approved status.
Friday night I engraved the receiver and then cut the barrel to 12.4”. I used a hacksaw to cut it off a little on the long side, then put the barrel in my lathe where I faced and crowned it. The Suomi barrel is about 19.5mm in diameter, so it just fit through my lathe’s 20mm spindle bore.
I touched up the muzzle with some Birchwood-Casey cold blue, and it’s a pretty close match to the TNW phosphate finish.
Aside from looking correct, it now balances much better. It’s not nearly as muzzle heavy and actually handles pretty well, even though it’s heavy.
I was going to shoot it today but about 2/3s of the way to the range I realized that I had forgotten my range badge and key. Hopefully I’ll be able to put some rounds downrange through it next weekend.