Sticky bolt on marlin 39

[uscra112]

Hadn't occurred to me. (adminsters dope slap). Revolver gunsmiths do that to "stretch" a hand that isn't rotating the cylinder all the way. The perfect solution for you.

Heating it that hot may have drawn whatever temper it had, though. Hope you cooled it down right away.

[Bazoo]

I’m guessing that temperature and I’m being generous. I heated the end maybe 10 seconds with my propane torch. Not enough that it got hot down on the handle, it still feels hard. I’ve tempered some knives and an confident I didn’t soften it at all.

[Bazoo]

I file tested it against the other bolt and both are the same hardness. I fitted it until it would accept a .045 rimmed Remington. Test fired it with aguila and Remington thunderbolts. It locked up I’m with the thunderbolts but the aguila was fine. It previously wouldn’t shoot them more than a couple shots without locking up. So I put some lapping compound on the mating surfaces and cycled it 100+ times. Shot some Remington and it it did lock it up but only one out of 18 this time. I’m thinking it needs to have the parts lapped more to mate them. Maybe just shooting it will wear them in enough. Not sure yet. Definite improvement though.

[Bazoo]

After thinking on it, I think the headspace being tight, and getting an occasional Remington that’s thicker rimmed, is causing the continued lock ups. Pinching a thicker rim would cause the bolt and lever to bind. I think I’ll measure some rims and cull out some thick ones and see, and maybe shoot it some with various ammos. Could be a bad batch of ammo in some way too.

[uscra112]

I think that's a good plan. Remington commodity ammo has been notorious for being sloppily made for at least a generation. I've done weight sorts that returned so pretty dismal numbers. I would be surprised if their rim thickness variation wasn't just as bad.

[Bazoo]

I opened the headspace up enough that it will accept the thicker rimmed ammo. It didn’t help. It is locking up with both thunderbolts and with golden bullets of new manufacture. It could be that I have fixed it for all others, and just Remington ammo don’t agree with the gun.

I did notice though that it will lock up solid if I fire it with the lever just short of touching the frame. Maybe .010 away.

I haven’t had the aguila lock it up since I’ve tightened the headspace. My buddy shot it today and it locked on him with aguila and I suspect maybe he just didn’t have it closed 100%.

The local gunsmith suggested that maybe something in the chamber was causing cases not to grab like they should. He suggested dirt from the Remington ammo. Since I do have some scratches in the chamber, I cleaned it and polished it with 1000 grit paper. I probably only polished the chamber 10 seconds using my drill. Not sure that would be enough to do much but im afraid to do much as I don’t want to open the chamber up. I figured if it was just a few minor burrs, it would knock the high spots off. While it never had extraction problems and ammo would chamber freely, there was some scores on the empties from the scratches in to the chamber. Not sure what’s going on as I don’t have a bore scope. I didn’t consider this a problem as it fed and extracted fine and since the headspace was generous, I just assumed it was all a headspace issue. Now I’m considering maybe the chamber being scored is causing some of the bolt trust.

Anyone have ideas in this? I’m not very familiar with polishing chambers. Anyone offer a link to a tutorial?

[uscra112]

I've always used fine crocus cloth or aluminum oxide paper on a balsa-wood stick. Balsa crushes to conform to the chamber shape. Being an RC airplane builder I of course have plenty around.

Flex-hone makes brush hones for bigger cartridges. They might have something for .22s.

Is it possible that the geometry of the lever face is such that it's going "over-center" the way toggle linkages do?

[Bazoo]

The geometry thing was mentioned to me by the gunsmith and when I fitted it I made sure it was not caming over. Make no mistake, it’s not “locking the bolt and I can move the lever some”, it’s locking both solid like a high pressure round in a bolt action rifle. When it locks the lever will not budge. Sometimes it takes a lot of force to move it. As if it was very high pressure.

[2152hq]

Does your 'local gunsmith' happen to have a No-Go gauge for a .22LR/
You really should start there and actually see what the set up currently is.
You mentioned that the lever closes w/a round in the chamber with just a little gap/daylight between the lever and the grip (.010 approx).
I can tell you from Factory experience at Marlin that that is the very picture the Final Assembler or Repair Dept Gunsmith wants to see with a No-Go gauge in the rifle and the lever gently closed.

HS should be checked with the bolt stripped but it usually is not.

Peening the lever to extend the arm a few .000" is a common repair on the 39 (and 97). It doesn't take much effort to accomplish, the part is soft even under a factory color case hardening on early rifles.
One thing to check is that after the peening is that the arm is then absolutely straight again and not twisted one way or the other.
During the peening, the metal will generally start to do just that twist and go off in one direction or another. It's just the way metal responds to the technique.
Not a big problem here. But make sure that tip is placed back in line where it belongs. It must engage the locking shoulder on the bolt squarely and not rub against the bolt when especially disengaging (opening the bolt after firing).
Even the slightest tweak in that tip can cause a hard lever opening and/or closing.
Check the side of the bolt where the lever runs along it in operating the bolt for any obvious signs of abrasions from the arm.

Check the cartridge guide spring in the top edge of the chamber.
It's planted in a recess betw the bbl and the frame and sits there only to guide the nose of the loaded rd into the chamber.
If it's bent it can jam up the bolt. You need to pull the bbl to remove it and replace it. Then reassemble the bbl to the frame.

The extractor should slide easily into the cut into the 3 oclock position in the bbl.
It should cam outward slightly on the cut in the bbl as the bolt closes. The point/hook on the extractor should only grab onto the case at the rim itself and pull it from the chamber.
If that extractor cut in the bbl is extended too far forward into the chamber, the fired case will expand into the open cut and the case can jam in that open cut sometimes depending on the ammo. Some worse than others. Some not at all.

It doesn't hurt to polish a chamber, but do just that,,polish it. Don't enlarge it or make it out of round in anyway.
Look carefully are the rear edge of the chamber and make sure the fireing pin isn't too long and leaving a burr on the chamber edge from hitting it.
That will make for tough extraction and can make all sorts of feeding issues as well if it gets bad enough.
RF Firing pin should fall a few .000" short of striking the chamber edge when struck.
Most used to be fitted to do just that.

About all I can think of at the moment.

[Bazoo]

Thank you for the suggestions. I forgot to ask the smith if he had a no go gauge. I could buy one though I spose.

I was aware not to make the lever end bent, I peered both sides evenly and it appears flat with t he rest of the lever. Though I didn’t put a straight edge in it, just sighted down it and it wasn’t obvious.

I didn’t strip the bolt but I see how that would be beneficial.

I will check the extractor cut, but best I recall it is not into the chamber. The firing pin is not hitting the barrel and there is no damage there.

I’m aware of the cartridge guide and it’s function and tuning. It feeds and extracts flawlessly.

I’ve read quite a bit on the gun, and all manner of problems associated with it. I have yet to come across a thread anywhere that has the bolt locking up like I do. If anyone is aware of a similar issue and could offer the link to it, I’d appreciate it. Sometimes the answer to a problem is just a search away using different wording.

I ordered the agi armorers dvd on it. We shall see if that helps any. I can y’all one thing. Few guns are as magical in their operations and use as the 39. If I can get this licked, it will be my favorite gun for a long long time.

[uscra112]

Check the cartridge guide spring in the top edge of the chamber.
It's planted in a recess betw the bbl and the frame and sits there only to guide the nose of the loaded rd into the chamber.
If it's bent it can jam up the bolt. You need to pull the bbl to remove it and replace it. Then reassemble the bbl to the frame.

My old 39 (Ballard rifled) has a spring in the frame, above the bolt, which might be this "cartridge guide spring". Acts to guide the nose downward into the chamber. Looking hard at it, I could believe that the end of that spring might catch the rim of a fired cartridge, preventing extraction. Especially if the rim has expanded on firing. (The rim O.D. is not supported in this design.) Fired case ought to show a witness mark once you get it out.

Taking the spring out of mine would not require removing the barrel. Just removing a screw from the top of the left receiver half. Is this different in a 39a?

Keep at it. I love puzzles.

Another thought: Measure the rim diameter of the rounds which bind the action and compare to rounds that don't. Are the bad ones bigger?

[uscra112]

Could the lever be catching on the lifter arm? Working the mechanism with two halves separated...looks possible.

[uscra112]

How far does the lever move before it binds?

[Bazoo]

The lever doesn’t move before binding. It is solidly stuck upon firing and then takes significant more pressure to move it. Once it unlocks, it cycles as normal.

The cartridge guide is not snagging the rim. And the carrier is not binding on the lever. It cycles without issue. But upon firing, will lock the bolt and lever unmovable except through greater than normal force.

[uscra112]

OK, only one more thing I can think of. There's the spring that holds the lever closed. End of it drops into a detent in the lever. Could anything be wrong there?

If not, I'm back to the cam surfaces.

[Gewehr-Guy]

One simple suggestion would be to re-snap the hammer on the breach block when it locks up. If it opens easily then, it would indicate its binding on the locking surfaces, rather than the chamber.

Another thing to look for is how much clearance is between the top of the bolt, and the reciever. If the bolt is worn on top,it can wedge upward and change the angle of the locking surfaces a bit.

Also, on my 70's model, the lever moves 1/4 inch off the frame , then retracts the firing pin about 3/16 of an inch, before the bolt starts to move. Could yours have a different style firing pin that could interfere with the bolt movement?

[2152hq]

My old 39 (Ballard rifled) has a spring in the frame, above the bolt, which might be this "cartridge guide spring". Acts to guide the nose downward into the chamber. Looking hard at it, I could believe that the end of that spring might catch the rim of a fired cartridge, preventing extraction. Especially if the rim has expanded on firing. (The rim O.D. is not supported in this design.) Fired case ought to show a witness mark once you get it out.

Taking the spring out of mine would not require removing the barrel. Just removing a screw from the top of the left receiver half. Is this different in a 39a?

Keep at it. I love puzzles.

Another thought: Measure the rim diameter of the rounds which bind the action and compare to rounds that don't. Are the bad ones bigger?

You are entirely correct! The cartridge guide spring in the 39 is held in with a small screw from the top of the frame.
I had a brain delete moment,,thinking of the same spring in the bolt action Marlin .22's. They are held captured inbetw the bbl and recv'r. They require the disassembly of bbl and recv't to replace.

Thank you for pointing that out!

[Bazoo]

The cartridge guide is not catching the rim. Also there isn’t any appreciable wear on the bolt.

The agi video was useless to me, I already knew all of that from my own observation and from my research.

After thinking it through more I think I have a 2 fold problem. One was excessive headspace and the other is a chamber burr causing casings to give too much bolt thrust. Some more than others. Originally before I did anything I had the locking up issue and I cleaned the chamber with a wire brush in a drill and the problem was better with some ammo.

Now I’m looking at polishing the chamber. I’m also looking at possibly replacing the barrel. This isn’t something that’s easily done it and is a last resort.

[uscra112]

If there is a burr in the chamber due to peening of the barrel metal by firing pin strikes, there is a tool to push the deformed metal back where it belongs. This situation is endemic in high round count .22 rimfires. Many of the old .22 caliber belly-shooting gamesters had this tool in their kit.

https://www.tandemkross.com/ChamberM...erIroningSwage

Stevens Model 44s and Favorites were changed about 1900 so the pin strikes on the extractor, probably for this reason. It hurt accuracy, but it surely reduced customer complaints.

More research seems to indicate that the Tom Menck tool (above) is discontinued everywhere. A reasonable substitute can be made from a hardened steel taper pin.

What you do NOT want to do is cut the burr away. That compromises the support for the rim where the pin strikes.

[Bazoo]

I know there is a tool for ironing out the firing pin peening. It doesn’t have that however. The firing pin doesn’t protrude past the bolt face.