Misfire on Marlin 336

[gambleone]

Hope someone can help. I have a Marlin 30-30 336 that has been misfiring about 1 every 5-6 shots. Seems like too light of a crater on the primer. I have taken the bolt apart & cleaned the inside with brake cleaner spray & long tips. I replaced the front & rear firing pins & the small flat spring in-between. I did not replace the hammer mainspring. Using Winchester large rifle primers. I'm kinda at a loss besides replacing the mainspring. It is an older rifle. Any thoughts.

 

[rockhound78]

I think you are on the right track and I would also replace the mainspring

 

[kevinbritvec]

If you are pushing the shoulder too far on your reloads you may be creating an artificial excessive headspace issue.

 

[Tommie]

If you are pushing the shoulder too far on your reloads you may be creating an artificial excessive headspace issue.

Not likely with a rimmed cartridge

 

[lb-ft]

Long shot but any chance you have brass with primer pockets that are too deep, or a burr in the bolt impeding smooth firing pin travel, or a transfer bar intermittently interfering with the hammer fall?

 

[lb-ft]

Thread 'Marlin 336 misfires'

Mar 23, 2014

I've got a 1968 336 in 30/30 that looks like new although I have put about 300 rounds through it. It misfires with either handloads or factory ammo. It leaves light hits on the primer.

The rear firing pin, bolt spring, and mainspring were replaced. They were out of front pins but I don't think that is the problem.

I smoothed up the bolt spring, firing pins, rear firing pin chamber, bolt, feed ramp, anyplace there might be drag. The bolt sat in Hoppes #9 for 3 days and cleaned using a bristle brush and drill. I put the original rear firing pin back in since it was tad longer than the...

• ba_50
• Replies: 9
• Forum: Gun Project Questions & Gunsmithing

 

[M-61]

If you are pushing the shoulder too far on your reloads you may be creating an artificial excessive headspace issue.

30-30 headspace’s on the rim.

 

[gambleone]

Thread 'Marlin 336 misfires'

Mar 23, 2014

I've got a 1968 336 in 30/30 that looks like new although I have put about 300 rounds through it. It misfires with either handloads or factory ammo. It leaves light hits on the primer.

The rear firing pin, bolt spring, and mainspring were replaced. They were out of front pins but I don't think that is the problem.

I smoothed up the bolt spring, firing pins, rear firing pin chamber, bolt, feed ramp, anyplace there might be drag. The bolt sat in Hoppes #9 for 3 days and cleaned using a bristle brush and drill. I put the original rear firing pin back in since it was tad longer than the...

• ba_50
• Replies: 9
• Forum: Gun Project Questions & Gunsmithing

Thanks for this. I will check it out. Never thought about primer pockets too deep.

 

[old codger]

Are these handloads or factory ammo?

 

[tmwinds]

If you are reloading, are you seating the primers snugly to the bottom of the pocket? Also might try a few reloads with different primers.

 

[ORjeff]

I started having a similar issue with my BLR years ago. It took a while to figure it out. When I was cleaning the primer pocket I was doing too good of a job and removing brass from the bottom, making the pocket too deep so the firing pin would only make a small dent with no boom. Now I have a drill guide bushing (used on a drill bit to keep from drilling a hole too deep, available at your local hardware store) set up on my pocket cleaning tool to keep it from going too deep. It took a little patience to get it set up right but it was totally worth it. I also started using a primer seater that sits in a ram press (RCBS, Lee, and Lyman make similar units). I install the primer in a batch of cases with my hand tool like normal and follow that with the ram tool to ensure that the primer is fully seated. Never had another misfire.

 

[gambleone]

Are these handloads or factory ammo?

handholds

 

[gambleone]

If you are reloading, are you seating the primers snugly to the bottom of the pocket? Also might try a few reloads with different primers.

Will do, thank you

 

[M-61]

I clean the primer pocket.
I never remove any brass, just clean
I never alter the flash hole in anyway at all, when using new brass I deburr in case there is is a piece the factory left there. That’s a one time process only. Burrs do not reappear. Lapua has the occasional burr just like any other make. Some say Lapua drills their flash holes. I don’t know or care if that’s true.
The primer should be seated to the bottom of the pocket and sit flush with the surface.
I usually sit the case on a piece of glass to see if it wobbles.

 

[kenhwind]

We had a Marlin 336 30-30 that would not fire all of the time. I tried everything.
Replaced parts, reloads factory, I still get emails from the Marlin forum, that rifle would not work for me.

My uncle has one and it has never failed him; he has used it hunting for years.

 

[M-61]

We had a Marlin 336 30-30 that would not fire all of the time. I tried everything.
Replaced parts, reloads factory, I still get emails from the Marlin forum, that rifle would not work for me.

My uncle has one and it has never failed him; he has used it hunting for years.

Still have it?

 

[gunsandgunsmithing]

I think you are on the right track and I would also replace the mainspring

Agreed, he's on the right path, sounds like. By far, the most common cause is old oil/dirt gumming up the free travel of the pins. If that's good, just make sure fp travels freely, check protrusion and if all looks good, I'd try a mainspring. Never seen the primer pocket too deep unless they were improperly cleaned/deepened..but I suppose it's possible. Check them against brass that goes bang with a depth mic. More likely IMO is the primers not bottomed out but I think you covered that. Might be worth a 2nd look though.

 

[swd]

After the obvious things like cleaning the pin and bolt and main spring and what does the firing pin indentation look like? I have seen lever guns that needed more protrusion. It needs be diagnosed how much each pin is pushing and which one to attack. It may need more at the back for the hammer to push farther or if the front doesn't have enough mechanical protrusion it needs to be modified. The system is a little more complex than it might seem to get the right balance at the front and back.

Edit, also many if not most of the lever guns I worked on also had excessive head space. Even new ones.

 

[N133]

30-30 headspace’s on the rim.

The rim can vary a lot. Just measured some 30-30 case rim thickness and they varied from .049" to .061". An .012" difference on that lot of brass, enough to cause a misfire on the thin rimmed ones if the firing pin protrusion from the bolt face happens to be a little on the short side and can be compounded even more if the primer pocket happens to be a bit on the deep side.

 

[JSH]

Yes it should headspace on the rim.
But if it was a run with last of a reamer could be undersized. Don’t laugh seen it on 35 Remington and 30-30 a couple of times. A bit of polishing fixed them
Virgin brass is just enough smaller it would chamber and fire with out any problems.
Some dies don’t size small enough as well.
How much primer protrusion do you have?