I'm looking to thread a heavy barrel PTR91. The muzzle diameter is about 17.9mm so 18mm should work. I cannot find 18x1.0mm TAT. Does anyone have one or know a company that makes one?? I can get the die and I guess I can make one out of aluminum or brass but it would be easier to buy one if it was not $50 or more. Liberty Suppressors has 18x1.0mm as a standard option for the Fixed Barrel Adapter. https://libertycans.net/product/fixed-barrel-adapter/ If none available I guess I will 'fire up' the mini lathe and get to work.