And this is why we have bolt shrouds on some rifles and other safety measures built into rifles to vent explosive discharges. It could see it destroying the rifle for instance a 30-06 and 300 win mag are different case diameters, I could totally see the chamber not sealing and gases going all over the place doing damage. The firing pin could definitely strike a primer if the extractor held the cartridge case from foreward movement, not to say that it could in all circumstances, but the speed of a firing pin drop and the and the strength of either the hammer or firing pin hitting the primer hard enough to go off. I over heard guy trying to tell a customer at a local gunshop, he was a well known to the gunshop, it was ok to fire 40 cal smith & Wesson auto pistol ammo in a 10mm auto. I couldn't help myself overhearing that conversation, I stuck my nose in it and told the customer this guy was full of himself and under no certain terms should he or anyone else try shooting 40 cal ammo in a 10mm auto and here's why , the pistol extractor is going to hold the case from going foreward and it's going to go bang, but you are probably going to break your pistol extractor or other things. Now if it were a Smith 610 revolver using moon clips that's a different story. That really ticked me off when I heard that if it had not been a safety issue I probably wouldn't have made a scene and pulled the customer to the side and tell him don't listen to this moron. The know it all got pissy with me and he told me he was a master re-loader, you don't want to know what I told him he was a master of something else and he better go back to re-loading 101 before he get's someone in trouble. My point is take things with a grain of salt until you know for sure, ask questions, then ask more questions. I learn something new every day in fact this old dog just learned how to put Strelok ballistic app on my smart phone and I just about impressed the crap out of myself with this new toy, I think I'm going to really like it, but I still will use range cards.