Marlin 336 RC misfire fix?

[ba_50]

Hi,

I picked up a 1968 30/30 in EC condition that misfires. The rear firing pin is pushed down so far from the spring that it hits the bolt and not the firing pin.

Is this a common problem with 336's? Did Marlin come up with a "fix" for it? One other shooter tried a new spring which didn't work either. He straighted the spring till it worked.

I'm going to call Marlin this morning but they will probably say it is to old to get information on or mail it in.

What is the best home fix solution? Thanks.

[Cast Bullet Hunter]

The two piece firing pin is a safety device, and the spring is supposed to push the rear section down out of alignment with the front section, that is how it works. When the lever is fully closed the locking block pushes the rear section up so it is properly aligned. This cannot be seen! All your friend has accomplished by bending the spring is to disable this safety feature. The reason for the mis-fires is somewhere else, such as a broken firing pin, burring in the channel or on the pin, old oil and dirt in the channel, etc. It could also be a former owner, when he had the gun apart, cut the hammer spring so he could get it back together, they can be difficult. Any local gunsmith should be capable of repairing whatever the problem is. These guns are quite simple, but you need to know something about what you are doing, as your friend has already proven.

[Leverdude]

You can relieve that spring & still have it disconnect the rear pin. Matter of fact it'll drop with no spring as long as you arent shooting upside down. In my 55 336 I kept getting misfires & eventually determined that to be the cause. I straightened out the spring until it positively pushed the pin out of alignment but no more, canged the rear piece & its been fine.

[gon2shoot]

I bought a 336 that had been sitting a long time.
First time out I had couple light strikes, checking the pin I found it to be pretty stiff so I cleaned it with spray cleaner.
I haven't had it out again but, I can feel by finger pressure that it's moving more freely.

[O.S.O.K.]

The two piece firing pin is a safety device, and the spring is supposed to push the rear section down out of alignment with the front section, that is how it works. When the lever is fully closed the locking block pushes the rear section up so it is properly aligned. This cannot be seen! All your friend has accomplished by bending the spring is to disable this safety feature. The reason for the mis-fires is somewhere else, such as a broken firing pin, burring in the channel or on the pin, old oil and dirt in the channel, etc. It could also be a former owner, when he had the gun apart, cut the hammer spring so he could get it back together, they can be difficult. Any local gunsmith should be capable of repairing whatever the problem is. These guns are quite simple, but you need to know something about what you are doing, as your friend has already proven.

+1

That's what I was thinking - he said it all. Take the bolt to a smith or dissasemble, inspect and replace any "fixed" parts with factory new replacements. Then try it again.

[Leverdude]

The problem I think is compounded by wear where the pin rides on the locking bolt. In my case I think it set down just a tad & peened the bolt where it enters ahead of the locking lug recess. One of the first things I did was polish the opening to rid it of any burs. Once that was acvomplished I put in a new spring & pin & found I could set the hammer on it & it would hold the hammer up. No amount of force could get it to move forward, no reasonable force anyway. At that point I swapped in a one piece pin & used it like that until I bought a 1893 without any spring. I found it still disconected reliably.
Then I tried my 336 with no spring & it was flawless. So I put the spring back & relieved it until it functioned properly.
With all the folks getting rid of the two piece entirely, something I will never advocate, I'm surprised people are unwilling to try simply relieving the spring a bit.

[ba_50]

I took the firing pin out and everything was clean. Thanks for explaining how the back pin works. The coil spring and everything else looks original. I haven't altered anything. The 30/30 headspaces on the rim so I can't see how reloads would cause a problem with headspace.

The rifle looks like new, so unless the headspace was set wrong in the first place...

[J Miller]

My 2005 vintage 1894 Cowboy .45 Colt has a problem with the rear firing pin as well. What is happening is that with the lever closed the locking bolt is putting so much pressure on the rear f.p. that sometimes the hammer just can't hit it hard enough to fire the round. All springs are factory OEM. A lot of this is the way I grip the lever and stock. I always hold the lever tight up against the stock. When I do that you can try to push the firing pin forward by hand and it will not move until I release my grip on the lever.
There is a miss fit somewhere and I've yet to get it totally fixed. I haven't modified the spring as of yet. Might be something to look at.

Joe

[ba_50]

My 2005 vintage 1894 Cowboy .45 Colt has a problem with the rear firing pin as well. What is happening is that with the lever closed the locking bolt is putting so much pressure on the rear f.p. that sometimes the hammer just can't hit it hard enough to fire the round. All springs are factory OEM. A lot of this is the way I grip the lever and stock. I always hold the lever tight up against the stock. When I do that you can try to push the firing pin forward by hand and it will not move until I release my grip on the lever.
There is a miss fit somewhere and I've yet to get it totally fixed. I haven't modified the spring as of yet. Might be something to look at.

Joe

I pushed on the firing pin with the hammer back and it went ok except it would go a little farther with a little extra push. Not enough to stop it from firing I wouldn't think. It definitely doesn't hit the primer hard enough. The only thing I haven't tried is putting a #10 washer on the end of the main spring or taking it to a gunsmith.

[TomF]

Reloads and misfires are due to the occasional deep primer pocket. Most every used gun I buy will be taken apart, cleaned and reassembled. You'd be surprised how much crud collects in the firing pin channel.


TomF

[Leverdude]

My 2005 vintage 1894 Cowboy .45 Colt has a problem with the rear firing pin as well. What is happening is that with the lever closed the locking bolt is putting so much pressure on the rear f.p. that sometimes the hammer just can't hit it hard enough to fire the round. All springs are factory OEM. A lot of this is the way I grip the lever and stock. I always hold the lever tight up against the stock. When I do that you can try to push the firing pin forward by hand and it will not move until I release my grip on the lever.
There is a miss fit somewhere and I've yet to get it totally fixed. I haven't modified the spring as of yet. Might be something to look at.

Joe

Joe,
Try it with the rear pin spring out. If it still binds on you you can wrap some emry cloth around a dowel of the right size & work on the locking block where it aligns the pin pieces. JMHO but I think alot of this is that spring is stronger than needed.

[ba_50]

It looks like there might have been some crud in the bolt after all. It fired 6 out of 7 times yesterday. Next time I take the bolt out I'll soak the end in Hoppes #9. The firing pin is still hanging up a little bit.

It's nice to know how the bolt works. Thanks for the suggestions.

[J Miller]

Leverdude,

Thanks, I'll pop that spring out and see. And I'll do the dowel rod if needed.


ba_50,

Marlin bolts are a piece of cake to disassemble. The only tools you need is a punch and a hammer to take out the two roll pins that hold the two firing pin parts in. However what I'd try first is removing the bolt from the rifle and getting a can of aerosol carb or break cleaner and hosing it out from all directions. That will most likely dissolve and clean out all the built up crud. The only thing it won't remove is any debris from say a blown primer or something solid like that. Don't forget to lube it afterwards, the cleaners will strip all oils out of the steel.

Joe

[ba_50]

Update,

It looks like some CCI primers were too hard. Had a misfire in a M70 too. The rear pin in the 336 was peened and dragging so I smoothed it up. Winchester primers seem to be ok, but I haven't shot it enough to tell if the fix is complete.

[marlinman93]

You can remove the spring and stone it a bit to make it lighter. The old Marlins often had this spring break or removed, and it still works fine, as gravity will drop it out of alignment when the lever is opened. Any spring tension at all is enough to assist gravity.