OK, I give up. The rifle came into the shop because the elevator was not rising. Apparently the elevator plunger retaining clip had broken or otherwise come off, and the elevator plunger no longer did its job. The plunger spring and retaining clip were missing. The customer had reclaimed the plunger. Checked for other broken or missing parts, and ordered the plunger spring and retaining clip. Installed the new parts, and the gun cycled dummies and live rounds normally. Straightforward so far. Went to test fire, and the firing pin just dimples the primer a tiny bit. I had not test fired prior to disassembly for the original complaint, but, of course, the customer indicates it fired just fine before bringing to the shop. I can find nothing wrong with the reassembly.
Researched what I could on the Internet. Re-watched Bob’s discussion of exposed rebounding hammer stroke systems. Disassembled and cleaned bolt body and firing pin tunnel, firing pin and rear striker. The only thing I found was a bit of swaged aluminum where the hammer strut can contact standoffs that support the hammer. Relieved and cleaned up this metal as well as the two front corners of the strut. Symptoms remain the same. Checked headspace. Bolt will not lock up when a 0.0065″ piece of masking tape placed on the head of a live round (sorry, no 30-30 headspace gauge at this time). Tape keeps the bolt from moving far enough forward to allow the locking block to rise to tip the striker into alignment with the firing pin tunnel. I believe I have the strut oriented correctly with the long lobe up. Maybe the mainspring needs more tension. Seems plenty heavy enough though. Any thoughts on this mystery?
Seems to me the gun is not in complete lockup. It is locked up enough to fire, but the striker may not be fully aligned with the firing pin to hand off the energy properly from the hammer blow.
I would do a process of elimination. Remove everything from the receiver that is not needed to fire the gun. Manually place a round in the chamber and try again. You will still need the lever and locking block (of course), but can do without the other parts like the elevator assembly.
Depending on if it fires or not, then you know if those parts are the problem or not.
Answer
Look at the marks on the locking block, see if it’s rising high enough in the receiver to push the rear firing pin into alignment with the front firing pin. If the locking block is not coming high enough, you can slightly bend the lever to get the locking block up a bit more. See what Bob has to say in the Marlin 336 course, it’s very similar. DC
Reply
Well now, this is mildly embarrassing. Being confident in the rifle reassembly and understanding the customer’s stipulation that the gun fired fine the last time he used it 1-1/2 to 2 years prior, I developed a mental list of things to investigate and recheck. Re-watching pertinent AGI videos, posting the problem on the forum, rechecking the reassembly and manual cycling, trying different ammunition, etc.
Apparently I hadn’t gotten to the ammunition part yet, because when I tried some old Federal rounds rather than the brand new-looking customer Remington rounds, the rifle fired perfectly normally. No hint of a misfire, and the firing pin dents in the primers of the two test rounds were both sufficiently deep and otherwise normal. The customer likes it. Just goes to show you, anyone can overlook a rather obvious cause to investigate right off the bat.
