Of course the receiver locking tab is the final confirmation that it fits. If you can’t get the receiver far enough in to push the lock tab back in place (and that can take some light tapping with a rubber mallet the first few times too!) then you do have a fitment problem.

Fortunately, Steyr’s service is excellent. I’m sure they wouldn’t mind working on your gun even with the TriggerTamer installed. If you do have to send it in be sure to first carefully examine your NATO stock’s trigger and the NATO trigger pack’s return spring so you can have them fix any deficiencies in those too.

Somehow, I think you and I are the only people to have ordered a NATO conversion stock (also got mine from CDNN). I trimmed down the “bump” on the stock (talk about committing yourself to a no-return scenario!) and started reassembling the receiver to the stock. Disappointingly, the receiver doesn’t seem to mesh properly into the stock, leaving me with a 1/8″ gap (maybe a little smaller). The problem is that I cannot get the receiver lock to go back into locked position now. This is quite frustrating, and I’m curious if you or anybody else you know of has had a similar problem. This is driving me nuts. My next option, I suppose, is to ship it to Steyr for a proper refitting (which means I will have to likely take off my TriggerTamer mod that I also made tonight on my NATO trigger pack).