Never had a failure to fire, except on an old Winchester semi-auto in 243. Bought it, didn't fire. Firing pin was broken. Took it back, they changed the firing pin, still broke on first fire. Traded it for a bolt action. Can't remember the model number, but they no longer make them. It was back in the early 70's. Had a Remington 1100 fail to load because it had a broken part in the loading assembly. Bought a spare part and repaired it myself. All guns to me, if taken care of will work fine.
Had cheap scopes get knocked off zero. Quit buying cheap scopes.
