Oh, this is a 5.45 conversion. I thought it was a 7.62. But anyway, I tried to cut the end of my FSB off with a tubing cutter, but didn't have the right wheel. Made a good scored line though, and was able to finish it with a mini plumber's hacksaw. Mine wasn't threaded, so I bought a die from carolina shooting sports and did it myself. And yes, this was my first time working on an AK. Surprisingly easy, I must say. Replaced the gas piston (had to drill out the dimples) and threaded the barrel in about an hour. Now, if I could find an American made wooden monte carlo style stock, I'd be done wi