That is what I thought. Drill and pin and live with it. Thanks
My point is if you think receiver to barrel tension/friction alone is sufficient to eliminate movement when firing, then a small pin (or even an old drill bit) is a good safety precaution (and also gives you an index point to where you previously set headspace).
And my concern is that w/o any sort of pin, you could potentially have enough movement of your barrel to detrimentally affect headspacing -- and while I don't think you'd get a kaboom situation after a few rounds, I also don't know that you wouldn't. Look at your locking block dimensions (or bolt lugs on AKs) -- that's the amount of steel that's required to safely and reliably stop the bolt carrier from moving backwards earlier than desired in the firing cycle (early in the firing cycle is when pressures/PSI peaks)...
