When I bought a target action a year ago not one of my 3 large shank barrels would screw on. All the barrel threads were within spec according to my measurements and the paperwork that came with the action. I ended up having to put mine on my lathe and opening the threads up a little. I was pretty disappointed in the overall fit and finish of mine. It looked like they machined it on a Thursday before a holiday weekend and inspected it on Monday still suffering a hangover. Almost all the threaded holes were undersized and most of the cut surfaces looked poorly finished. I'm guessing I got one near the end of the tool life cycle.