French 303 did this to me in '80s
I used to work on a shop that was established way before '68 so we had all sorts of old odd stuff. I bought a bunch of french mfg 303(may still have some, kinda sorta collect cartridges) It was dated in the '50s I think, and without fail, every round would hang like a flintlock, click bang. Never a dud in around 1k rounds, but still... I dont open the bolt for at least a minute, usually shooting multiple guns so that no problem. never had one go off after ~1 minute, but I open them quick when i decide to none the less. An interesting aside, was shooting an FN-49 Egyptian 8mm, with that two piece firing pin and sure enough it broke and bolt only partially closed when went off, peppered my face and blew my hat off, felt like got hit w/ a board. Was ok, looked sunburned, cant believe rifle didnt blow up. Replaced firing pins/springs, tied her to a car tire and fired a mag through it and all ok, though I havent shot it for 10 years, shot a few hundred after tire test and ran like a clock. Those FN-49s are known for this so be carefull. I cant remember, I may have put in a one piece firing pin in it, been so long. I have seen dozens of guns destroyed by muzzle obstructions, most shotguns used by duck hunters. be careful. people dont shoot my guns w/o eye protection.