ive tried switching caps(cci,winchester,ther german rws)ive tried switching nipples taking sandpaper and thinning the top.it will do this to a usket nipple.i took lock off no gunk on inside.i put lock back on and shimmed it so it strikes the cap perfectly center of hammer.ive even took some sandpaper and lightly sanded the section where the hammer travels on the lock.ive had charles dalys,tradations and never had this problem.all it does is push the cap down on the nipple to where i cant remove without a knife.when it does that it will fire everytime.i even called cva to ask a tech and there response was the lock spring was weak(the bobcat was purchased new at walmart).its sentimental to me as my mammaw bought it for me and she has passed a few years ago.i killed my biggest buck ever with it and i had to pur a little powder under the nipple to get it to go off.my cva hawken does the excat same thing.its aggervateing.my hammer strikes the cap perfectly center and i cant figure out why it wont bust the cap.ive tried the cva perfect nipple,tradations nipples and get the same results.i have a musket nipple on it now and it will pop 6 out of 10 times.when i use a number 11 its 3 out of 10.the bobcat is a accurate little muzzleloader when i get it to go off .would like to get it right to use it again.ive got my trusty tradations ebolt 209 inline as my daily shooter but those sidelocks are calling my name to get used.ill try and sand some more where the hammer travels on the lock and see if that helps more.i think she gave 59 bucks for that thing back in 1999 and ive shot 3 deer with it but have pulled the trigger quite a few times and zilch.ive3 done shot 2 so far on this muzzleloader hunt and may try and take thursday when im off to see if it will not let me down.thanks for the tips greatly appreciated