Used this to thread the barrel on my mak 90 Sporter. My barrel had the machining marks and it was not a problem. Use a vice and watch a couple YouTube videos and you should be gtg.
Definitely take your time. Oil is you friend, use it liberally. This was actually a fun little project. It came out awesome.
Bought this to thread the barrel of my Norinco MAK 90. Once I got the cuts started it was a simple process. Just remember to take you time when making your threads and lube the tool as you making your cuts.
Also remember that this is a LEFT Hand thread so the old "righty tighty, lefty losey" phrase Does NOT Apply.
At first had issues with the threads on the guide rod but after working it through the die with a lot of effort, it cleaned up the threads.
On a barrel with some cutting oil, it cut the threads no problem and the muzzle break screwed on easy. If you are looking to thread your barrel then this will get it done.