Ithaca m37 locks up

[njluger 5]

I have an old Ithaca m37 (circa-1954) that I'm having some issues with. Every so often, the gun locks up after firing a shell. By "locks up", I mean that I fire a shell, and when I go to slide the pump back, it's stuck - I can't pump it back and therefore cannot extract the hull. I've been able to clear the jam, by very forcefully sliding the pump. When I mean forcefully, usually I need to prop the butt stock against the ground and putting all my weight on the pump, I can extract the hull. Yes, I look silly doing it in the field.

 

Can't figure out what could be causing this. Most of the time, the gun cycles just fine and the action is nice and smooth.

 

Anyone have any recommendations on a gunsmith who knows these old Ithacas in central NJ? I think all she needs is to be broken down and cleaned...action hasn't been apart since the 1960's! It's a passdown from the grandfather so I'd like to keep her running!

[Underdog 1,593]

Are you using 2 3/4 inch shells?

[axeman_g 128]

I had the exact same issue with a M37 in 16g. It is not the gun, and your are not going crazy. The problem is the ammo.

 

Does the gun unbind after about 3-5 seconds? What I found and I could never prove it 100%, it was purely a theory, but it held true. If you shoot cheap rem, estate, win etc etc shells... the thin brass OR the plastic heats up and expands momentarily locking up the action. What always confused me was.. why in Ithaca's only? Does not happen in my Rem 870s, Mossbergs or god forbid a semi like my A5.

 

Only gun I ever had the issue, and if I shot some high brass loads, never happened. Thats my two cents..

[djg0770 481]

I've had similar issues w my 12 ga m37 as well. I polished the barrel and cleaned up the slot in the barrel where the extractor rides.

 

For the record I have had more problems w the bulk Walmart shotgun shells than with Remington gun club shells.

[njluger 5]

Are you using 2 3/4 inch shells?

 

Yes, all occurrences have been with 2 3/4 shells - all brands, Winchester AA, Remington Gun Club (happens more often it seems with this brand), and Estate.

 

I had the exact same issue with a M37 in 16g. It is not the gun, and your are not going crazy. The problem is the ammo.

 

Does the gun unbind after about 3-5 seconds? What I found and I could never prove it 100%, it was purely a theory, but it held true. If you shoot cheap rem, estate, win etc etc shells... the thin brass OR the plastic heats up and expands momentarily locking up the action. What always confused me was.. why in Ithaca's only? Does not happen in my Rem 870s, Mossbergs or god forbid a semi like my A5.

 

Only gun I ever had the issue, and if I shot some high brass loads, never happened. Thats my two cents..

 

Yes, it seems if I sit there for a while and then give it a good whack to pump the slide, it frees up and the hull is ejected out the bottom. Interesting thought about the high brass ammo...what's inexpensive that's high brass?

[lunker 274]

I find that it is always easier if I rack the pump immediately after the shot is fired. If I wait, it requires more force to rack it. I always figured that either the hull was expanding or was getting the chance to catch on a small ledge or unpolished surface.

By the way (I'm sure you probably know), but your M37 doesn't have a disconnector either. It is fun doing a four round rack and shoot.

[axeman_g 128]

Try some Fiochi Pheasant I believe it is called. Real nice and not super expensive... about double the Win AA. And yep the Rem GC was the worst offender for me.

 

I like to think the Ithacas just had tolerances that tight, that even the expansion of the thin brass was not accounted for in those older shotguns... FYI I had a NEW Ithaca 16g that IT DID NOT lock up ever. It just patterned 12" left of POA (HA!) I really thought I forgot how to shoot for a few weeks there.

[lunker 274]

FYI I had a NEW Ithaca 16g that IT DID NOT lock up ever. It just patterned 12" left of POA (HA!) I really thought I forgot how to shoot for a few weeks there.

 

That would be upsetting. Especially for the gun that has the rep for the truest barrel because of the receiver lockup.

[axeman_g 128]

I was not impressed with my NEW ITHACA shotgun I bought in 2000. I would hope they got it fixed.. I am sure it was a fluke... they sent me a check plus shipping costs and transfer fees. I just could not push myself to get another one... and about two weeks later I laid my hands on my sweet sixteen and never ever looked back

 

 

[Parker 213]

It could be the shells you have, combined with a rough chamber. The steel bases today that are washed with brass, copper or zinc/nickel coatings are not as forgiving as the old-style brass bases. That's an easy issue to cure.

 

I would also check the action to make sure it's functioning properly. One thing that prevents the bolt assembly from moving rearward after the hammer falls and strikes the firing pin is the action release lever tab (slide stop) in the trigger group which drops down out of the way of the rear tab of the bolt assembly.

 

Read this link, look at the pictures, and ensure everything is working properly with yours: http://www.ithacaown...php?f=20&p=1523

 

 

Note: the trigger group, bolt and carrier assembly are removed from the rear of the receiver, so the buttstock needs to be removed if you need to get at them.

[jrfly3006 42]

+1 for the combo of dirty chamber and shells heating up after being fired and getting a little sticky in that chamber...our rem 870's at work have trouble sometimes ejecting slug shells when they start getting hot... like Lunker said eject that sucker as soon as you fire it might help