hi this is my first post here. I got a 336 off my buddy awhile ago and i looked up the serial number and if i remember right it was made in 1977. Now when shooting i have to fire, pull the hammer back and shoot again to set off the round. i replaced the hammer spring with a wolf extra power spring and the problem persists. Also the primers appear to be backed out even with reloads. Does anyone here have any ideas? I cleaned the gun when i first got it, but i never took down the bolt, i am going to completely take down the bolt and clean it thoroughly when i am done posting, thats the first thing i am going to try. Has anyone else had this problem or heard of it or how to fix it? Thank you.