i shot about 30 of the cci shells i had left through my other 22mag and all fired. i tried a clip full of super x in the marlin and two misfired, so it wasn't the bullets. after comparing the spent hulls from three different guns i could tell the marlins firing pin wasn't making the same mark as the other guns. i removed the firing pin and sure enough the striker end that hits the rim of the shell was defective, instead of it being square it was rounded with a small crater like a welding pit. i reground the the tip of the firing pin and it works fine now, makes a good heavy mark and has fired all the rounds so far. i got in contact with marlin and they are sending a new firing pin to my local gunsmith. the person at marlin told me that they have had a few of the guns come back with the same problem.