Marlin 39A feeding problems - please help

[B. Adams]

I bought a used Marlin 39A, late 70's production. I got it home and cleaned it up, then tried to cycle a magazine through it. I had many failures to feed, most noticably when I tried to cycle it somewhat quickly. It seemed that if I cycled it slowly it fed more reliably, but would still lock up occasionally.

I've read of problems of feeding with these, but most of the ones I've seen involve the tip of the bullet jamming on the top of the chamber, and the fix is to either clean the gun or adjust/replace the extractor.

However, in this case, the tip of the bullet is jamming on the inside of the receiver, below the chamber, as seen in the first photo. I also included a couple photos of what I believe is the cause of the failure to feed. The bolt has a ramp on the front of it, that lifts the cartridge up to the bolt face as it closes. You can see this little ramp pushing on the back of the cartridge in the second and third photos. My feeling is that this ramp is too long, which is pushing the cartridge forward prematurely, and my instinct is to shorten this ramp by approximately 1/32". But I'm no gunsmith, and I don't want to screw something up and damage this gun, so I'd like to get opinions on this before I proceed.

What is the best way to fix this problem? Will filing down the little ramp on the bolt solve my problem, or is there a better way?

 

[BamBam-31]

How's the cartridge guide look? It's a little flat spring on the ceiling of the receiver. I'd suspect that first.

Edit: Wait, looks like it's jamming before it gets to the guide. Sorry, dunno why it'd jam that way. Best of luck, though.

 

[BamBam-31]

Hopefully, you'll catch dfariswheel's eye w/ "Marlin 39a" in your title....

 

[Fast Frank]

In those pics, it looks to me like the carrier isn't going all the way up.

The point on the extension under the slide should go under the bullet, not behind it.

I'll dig mine out and look at it...

will post more later.

 

[Fast Frank]

Mine is different. there's a spring loaded plunger where the lever meets the lifter.

My lifter is much higher than yours is in the pic.

Look at the point where the lever causes the lifter to move up.

Is it worn/damaged?

 

[Fast Frank]

Here's a vid I made a while back showing the action...

Click on the pic to watch it, and when it comes up hit the full screen button.

See how high the lifter comes up? you can clearly see it above the bottom edge of the ejection port when it's putting the round in the chamber. Is yours doing that?

 

[dfariswheel]

DO NOT FILE OR ALTER THE "RAMP" ON THE BOLT. IF YOU DO YOU'LL COMPLETELY DESTROY THE BOLT.

The small ramp on the bolt really has nothing to do with the chambering cycle.
The "ramp" is really to release the NEXT cartridge from the magazine and allow it to slide back into the "next to feed" position.

In a properly working rifle, the cartridge should not be able to catch the rim on the triangular "ramp".

FIRST STEP:
Try a different brand of ammo. Could be this rifle just doesn't "like" your present ammo.

How the Marlin works:
When the lever is operated, the cartridge that's laying on top of the cartridge lifter's freed trough is lifted up to the feed position.

When the bolt is moved forward by the lever the cartridge is pushed into the chamber, and the lifter drops back down.
When the bolt fully closes, the triangular "ramp" presses inward on the cartridge stop in the left wall of the receiver, and the next round in the magazine is allowed to be pushed back onto the cartridge lifter.
When the bolt is fully closed, the "ramp" forces the bolt into alignment with the chamber.

DO NOT file or stone the "ramp" since this is not the problem.

Things to look for:

Check the triangular ramp for sharp edges or burrs on the RIGHT side, that might be catching on the cartridge.
This ramp should be far enough over to the left side of the receiver when assembled, that the cartridge rim should not be able to be caught on it.

Look for a bent cartridge lifter. Cartridge lifters are loose enough in the receiver when disassembled that there is considerable movement side to side, BUT the lifter should be flat and not bent or warped.

Check the rear of the trough in the cartridge carrier for impacted fouling or for burrs that might be preventing the cartridge from sliding back far enough.
If there's a problem with the trough, the cartridge may no move far enough to the rear, and the bullet nose may jam against the receiver face below the barrel.
This causes the same problem as an over-long cartridge.

Check the cartridge carrier rocker (the spring loaded lever in the cartridge carrier) to make sure it's free to move in and out, has good spring tension, and shows no unusual wear or signs of being altered.

Check the notch in the operating lever that interacts with the above carrier rocker to insure it's not worn or altered.
If either part is worn or altered, the carrier may not be pushed up high enough, or the "timing" of operation may be off.

Check the firing pin lug to insure it's not been altered or worn.
The firing pin is a critical connection between the lever and the bolt.
If the lug is worn or altered, the bolt may fail to "time" correctly.

Look for sharp edges, burrs, or fouling on the underside of the barrel and the face of the receiver around and below the barrel.

Look at the cartridge guide in the "roof" of the receiver. This is a flat spring that guides the cartridge into the chamber.

If your rifle has a cartridge guide in the RIGHT wall of the right receiver half, check to insure it's present and working freely with good spring tension.
The early Marlin's used a formed flat spring in a slot in the right receiver wall.
Later rifles used a heavy steel bar in a bigger slot in the right receiver wall.
Late rifles have no guide at all, and no slot or opening in the right receiver wall.

Check ALL parts for signs of alteration or "polishing". Since this is a used rifle, God only knows what a previous owner might have done to it.
Trust NOTHING, suspect EVERYTHING.

Unless and until you diagnose EXACTLY what the problem is, and determine the correct repair, do NOT alter ANYTHING.
"Shooting blind" in the hopes something may correct the trouble is how small problems get to be major expensive repairs.
If you can't detect the actual problem, take the rifle to a gunsmith.

 

[351 WINCHESTER]

My 39a was doing the same thing. I took it down and had to adjust the carrier screw as it wasn't allowing it to come up high enough. Those 39a can be a little tricky.

 

[B. Adams]

First of all, I just want to let you know that I haven't done anything yet, other than make sure it was clean. I did try some different ammo, Remington Golden Saber, which did work a tiny bit better than the Federal bulk that I was using previously. It still jammed a lot though, so that shouldn't be the issue.

I checked the lifter, and it seems to be undamaged and working properly, and there are no burrs or rough edges on any parts. The cartridge lifter seems to be fully capable of lifting the cartridges effectively. FWIW, the lifter does lift further than in my photos, but I didn't post a photo of it because I didn't think it would be relevant. It raises until about 1/8" of it is visible from the outside of the gun.

The "cartridge carrier rocker" does show some wear, but the tension is good and seems to allow the lifter to raise to its proper position, even under some pressure. The notch in the operating lever appears to be in very good condition. The firing pin also appears to be in original condition. All in all, the internal parts appear to be in their original, unmodified condition. There is a gap between the "cartridge carrier rocker" and the lifter, of about .025". Could this be causing the lifter to be slightly too low as the bolt comes forward?

The guide spring in the top of the receiver appears to be flush with the receiver, and not really "springy" at all. This part may need to be replaced, but does not appear to affect this particular malfunction.

The "ramp" on the bolt that i'm speaking fo does not release a cartridge from the magazine, this is done by a protrusion on the bottom of the bolt. It does, however, guide the bolt to the proper spot when you close it, but I don't believe it controls vertical movement, just horizontal (i.e. keeps the bolt from coming out of the side of the gun).

In summary, the lifter seems to be lifting effectively, and everything else appears to be in good condition and functioning normally. I included an altered photo of the second from my original post, which may explain why I think it's the "ramp" on the bolt that's causing the problem. You can see where I crudely labeled the "ramp" I'm speaking of, the magazine release that lets the next cartridge out of the magazine, and where the tip of the bullet is impacting the receiver. Also, if you look to the back of the cartridge, you can see the gap between the rim of the cartridge and the back of the lifter, which is made by the "ramp" pushing the cartridge forward. This is why I think that "ramp" is too long, because it seems like it's pushing the cartridge forward before the lifter has fully raised. I could easily be wrong about that, but it seems to be the easiest solution I can come to.

Thanks for all the help so far, I really appreciate it. I took this gun out to test fire it, and it was so fun to shoot. I really, really, really want it to run right. It would be a blast to shoot if it didn't jam every other round.

Thanks again for all the help (great video, BTW), and hopefully I can get this figured out (without taking it to a gunsmith). I look forward to any other suggestions on how to fix this, or what I need to do differently.

 

[Seven High]

I suggest that you send your 39 to Marlin for inspection and service. My 39 will feed any 22lr ammo with out a problem.

 

[Fast Frank]

well, if the lifter is coming up like it's supposed to, it should work.

I'm running out of ideas.

The only other thing I can think of is the "Too simple" answer...

How tight is the take down screw?

If that thing is loose enough to allow the receiver halves to shift just a little bit, it will foul things up.

I like to use a quarter on these, and I bear down on it just enough that it is just starting to deform the quarter.

That's pretty snug, but not screwdriver tight.

If yours is just finger tight, it could be a factor.

 

[B. Adams]

I tried tightening the thumb screw, and actually that seemed to make a noticeable difference. It still locked up fairly often, but probably only a third as much.

I'm considering sending this to Marlin for a tune-up, but their website seems to be down. Does anyone have a phone number for Marlin's service department? Otherwise I'll just wait until their site gets back up for me.

Thanks again for all the help so far!

 

[bcp]

I had a 39A in the 1950's that would feed anything but Federal.

Your cartridges look like they have a flat nose and a little longer bullet than normal. Try some of the more traditional shaped round nose bullets.


Bruce

 

[dfariswheel]

I'd talk to Marlin on this one.

If you alter the bolt and that isn't it, you may have to buy a new bolt, which will require fitting. All Expensive.

Marlin's are too expensive to just start altering parts, and without actually inspecting the rifle no one can give you really definite info over the internet.

Here's the repair info from Marlin's web site:
http://www.marlinfirearms.com/customersupport/repairs.aspx

Address and phone:
MFC
100 KENNA DRIVE
NORTH HAVEN, CT 06473
PHONE: 800-544-8892

 

[BamBam-31]

I recently sent in my 39a to Marlin for service. Turnaround time was about two weeks, and they really went the extra mile. I wouldn't hesitate to give them a call. You're right, the 39a's, when functioning correctly, are a hoot to shoot! Send it in--Marlin will make it right.