hard to say exacly what it might be. first off take the recoil pad off, then the forearm and then the barrel. take some canned air or a air compressor and give the reciever a few good blasts. if i had to guess, just based off the description given, id say there might be a washer in the stock that somebody forgot to put in before the screw. there shouldnt be anything other then the transfer bar fitting a loose in the NEF/H&R rifles. i have done a bit of fitting on my H&R rifles but even before that they are all tight fitting guns that lock up like a bank safe.