I recently bought a junker Marlin .22 bolt action at a show for $25 but I'm having a little trouble with it (as I expected). It will only fire about 1 in 5 tries or less. It gives a dimple on the case each time, but when it does actually fire the dimple is stronger. What could be cuasing these weak strikes (but not always). I've taken apart the bolt, cleaned it and oiled it, the firing pin looks good and the spring seems strong(?). I've also noticed that when I push the bolt handle down after cycling it, the cocking piece (the thing all the way at the rear) moves in a few milimeters (perhaps it decocks?). If anyone could tell me what the problem is and how to fix it I would really appreciate it.