Marlin 336CS problems

[Woogie Bear]

I need some help and figured I would come to you guys first. I am trying to fix a Marlin 336CS for a buddy of mine. He has had it since he was a kid and always used it for hunting. Took real good care of it and never put it away dirty. He says about 3 years ago he took it out to go shooting and it wouldn't fire. The firing pin was leaving dents in the primer so he thought maybe he had a bad batch of rounds. Got a new box but was still having the same issue. I have taken it completely apart and can't find anything wrong with it. I was thinking that because it is an older rifle that maybe the firing pin got worn down over time from repeated use or maybe he was using cartridges with tougher primers. I can't figure it out myself. What do you guys think?

Also, I found a sight where I can get firing pins. They have two different styles for the same rifle. Both of them look very different in appearance but they supposedly work for the same rifle. Not sure if I should go with the new style or old. What do you guys think? The links for the 2 firing pins are below. Any help you guys can provide would be greatly appreciated.

https://www.gunpartscorp.com/Products/406640A.htm

https://www.gunpartscorp.com/Products/1054460A.htm

 

[Roaster's Gallery]

What did the hammer spring look like when you had it apart? May have been shortened at some point. Did you take apart the bolt & clean the firing pin channel good? If it is a 30-30, there shouldn't be head space issues, but a 35 Remington head-spaces from the shoulder of the ammo, so there could be an issue there. I would put a small washer or two under the hammer spring to get a stronger hammer strike, see if the spring may need replacing.

 

[Roaster's Gallery]

Another problem that could occur with a 2 piece firing pin - the locking bolt can be worn at the top, where it pushes the rear firing pin into position to strike the front firing pin when the hammer strikes. Make sure the lever is completely closed when firing.

 

[Woogie Bear]

Thanks for the info. I will take a look and see if maybe that is the issue. It still seems to have a lot of force behind it and he said it was leaving dents in the primer although he never thought to compare one that fired and one that didn't. Do you think it's some that I should replace anyway? I am new to working on lever actions and would rather go overboard on trying to diagnose and fix the problem rather than not having it fixed the first time.

 

[Roaster's Gallery]

I wouldn't replace the front firing pin before ruling out weak spring, clean firing pin channel, rear firing pin in proper position when lever closed and locking bolt properly aligning rear pin. Empty gun of ammo - empty it again - lever gun to cock hammer - make sure lever is closed - point gun in safe direction - push on rear firing pin button with a rod of some sort to see if it moves forward with ease. remove lever and remove bolt. Flip it upside down and familiarize yourself with the two piece firing pin gap - push the rear section into the channel & see if you can move it freely. Shake the bolt in a way to see if the front firing pin rattles back & forth freely. My experience has always been gunked-up lubrication causing firing pin(s) to not move freely. The reason a new firing pin always works - the bolt gets cleaned when owner takes it apart to replace pin. 30-30 or 35 Rem?

 

[Roaster's Gallery]

Oh - ask your friend if he ever uses WD-40. I have made a few dollars buying Marlins that wouldn't work, removing the WD-40 residue, then selling as operational firearms.

 

[bobinbusan]

Had that same problem years ago and it was the firing pin and thinking it was broken and in 2 pieces, replaced it and was good to go.

 

[Woogie Bear]

Roaster- disassembled the bolt and firing pin and cleaned it out real good. Everything seems to be functioning smoother now. Unfortunately I accidently bent the extractor ring and now its out of true. Kind of a bummer. I'm gonna get a new one on order, put it all back together and hopefully that will fix the problem. For now I am gonna use the same firing pin because I am pretty sure it was just fouled up pretty bad. I tried your method of testing the firing pin and there was no movement at all. I think its caused by the spring that goes into the firing pin. It looks like its pressed up against the other part of the firing pin. We shall see.

 

[Roaster's Gallery]

I hope it works for you. A one piece firing pin is an option, but using one of those bypasses an important safety feature of the two piece system.

 

[Woogie Bear]

Shake the bolt in a way to see if the front firing pin rattles back & forth freely. My experience has always been gunked-up lubrication causing firing pin(s) to not move freely. The reason a new firing pin always works - the bolt gets cleaned when owner takes it apart to replace pin. 30-30 or 35 Rem?

Is the front firing pin supposed to move back and forth freely? I figured the firing pin spring would prevent the firing pin from moving around a lot. It seems that there is a decent amount of pressure the spring is putting on the rear firing pin.

 

[Woogie Bear]

Oh, and its a 30-30.

 

[Roaster's Gallery]

You bring up a good point. In any case, with the bolt out, you should be able to push the front pin to see if it moves freely, and protrudes enough through the bolt face to do it's job. If I find a good video on the 336 bolt, I'll list the link here.

 

[Woogie Bear]

Everything looks to be in good working order. There was some grit in the firing pin chamber. Now I just have to get it to the range to see if it works. Not sure when that will happen but I will let you know if it works out. Thanks for all the help.

 

[Woogie Bear]

I was able to take my buddies rifle to the range today and it worked flawlessly. I wasn't able to shoot it as I am still recovering from shoulder surgery but I had two friends of mine put 13 rounds down range and it didn't have a single issue. Thanks go to you guys for your advice. I really appreciated it.

 

[Big Shrek]

Usually the only two things that bug a Marlin are failure to properly clean
and old, worn-out springs

See how springy you are after 40 years!!
Too bad we can't just swap ours out as easily as a Marlin's!!