I have a problem with a 15-2. It misfires occasionally. More often when shooting DA, but sometimes when SA. The cartridge has a slight dimple on the primer, but does not fire. The same cartridge can always be fired on a second attempt. The ammo is my handloads, but it works perfectly in other guns. I notice that the upper part of the hammer is striking the frame hard enough to leave a mark. Could the contact between the hammer and frame be enough to reduce the energy applied to the transfer bar? Might a light polishing of that part of the hammer face help? Any suggestions?