Marlin Bolt Disassembly

[GregLaROCHE]

I have a Marlin in 45/70 from the eighties. I’ve been having some misfires, so have decided to replace the the multi part firing pin with a solid one. When breaking down the bolt, the last step is to bend back a keeper, that is cut out of the side of the main body of the bolt. I worry if I bend it to remove the firing pin and then bend it back, it may work harden and snap off. Can someone give me advice on how to do it.
Thanks.

[oconeedan]

Greg, I can not answer your question. But I have had the same problems you have and found a couple of issues that contributed. Especially since I started using CCI34 primers, which are known to be hard. First, there was fouling in the bolt that could have been rubbing on the firing pin, slowing it down. 2nd, through experimentation using a hammer spring kit (Paco Bills?) from Brownells, I determined that the threshold for the hard primers to fire reliably was 3lb 4oz, measuring the HAMMER by pulling on the hammer spur with a Lyman digital trigger pull scale.
I eventually ended up using a small brass washer, over the hammer spring strut, to shim the hammer spring and make it a tad stronger. I am still using my 2 piece firing pin. The force needed to pull the hammer back is now 4lb 14 oz, well over the threshold for firing the hard primers. And my trigger went up to 3lb 1oz, which is acceptable to me for a hunter.
I ended up not using any parts from that hammer spring kit, and only using a little washer from my spare hardware parts.
Dan

It is weird, and maybe total coincidence, I have not had this issue with other Marlins I have owned, only my 45-70.

[MostlyLeverGuns]

A 'keeper' on the bolt? My two Marlin 1895's (1980 and a Remlin)have the same parts, the bolt body, the extractor, two roll pins(one is under the extractor), front firing pin, rear firing pin, and a thin spring that offsets the rear firing pin spring. Disassembly consists of removing the extractor then driving out the two roll pins, the firing pins slide out with the thin flat spring. After cleaning, maybe polishing the firing pin tunnel in the bolt, the one piece firing pin slides in and the roll pins are driven in and extractor replaced. The bolt has a groove for the ejector, but I haven't seen a 'keeper' on a Marlin bolt (36,336,1894,444 or 1895). I have installed Wolf extra power springs in my Marlins along with a one piece firing pin in a few, but have not experienced misfiring unless headspace was in question. Marlin's will sometimes fire with a broken firing pin with just an occasional misfire. Some Marlin's have a second groove to place the hammer spring adjusting plate to increase spring pressure.

[GregLaROCHE]

Thanks Mostlyleverguns. I’ll have another look at it. It’s been awhile since since I got the new firing pin. I was postponing the project because I wasn’t sure. If it’s only roll pins that’s no problem.

The gun has had a long and hard life. I’m not surprised that there isn’t some wear in the two part firing pins. When it misfires, I only have to recock and it fires. I’ve had the bolt apart and thoroughly cleaned it. I rinsed the inside of the bolt where the firing pin is with solvent. I was shooting BP in it and at first that was the problem.

[MostlyLeverGuns]

I have come across round bolt Marlin's (336,444,1895) that have the rear firing pin just slighting dragging on the firing pin hole when hit by the hammer. Lowering the hammer all the way on the cartridge, then going to safety pushes the rear firing pin into alignment, helping with firing pin impact and avoiding the drag. Sometimes the rear firing pin develops a slight mushroom that slows the firing pin strike, wear on the locking lug can also keep the rear firing pin from properly aligning as it is that locking lug that pushes the rear firing pin into alignment with the front firing pin. I usually will slightly round the bottom front of the rear firing pin to avoid this problem. Straightening the little flat spring that pushes the rear firing pin down reduces friction and also helps reliability.

[upr45]

I like silicone spray which dries as a lube after cleaning for things i don't want oil residue on. I test it to make sure it dries. Silicone spray is available at most hardware stores