Winchester M94 Feed Jams

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Aaron posted this 1 weeks ago


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Aaron posted this 1 weeks ago


The situation description is as follows:




The gun is a Cimarron Arms (Uberti) Winchester M94 in 38-55 Winchester


It is brand new having only fired about 12 rounds – all single fed.


The gun will cycle 30-30 rounds just fine with their bottle-necked presentation and smaller caliber bullet which centers itself on the feed.


Every 38-55 round will jam up tight while getting fed from magazine.


The jam in a horizontal position AND a vertical position.


I am levering the gun hard. That only jams them up tighter.


3 different cast bullets (cartridges) jam.


I am using both Winchester brass with .377” bullets AND Starline 2.080” brass with .380” bullets.


Bullet crimps are deep and smooth.


Cartridge overall length is within limits (especially with the 2.080” brass).


Jamming occurs BELOW the crimp about 1/10” lower.


It seems the cartridges are too long to feed properly and get jammed on the angle each time.




Having researched this on the available chat rooms and web feeds, I have eliminated all the silly causes of these jams as well as the busted lifter theory and the guide rail springs etc.. These rifles are modeled after the pre-64 rifles with their internals.




I suspect that the Six O’Clock position of the breech face is grabbing the cartridges and may need to be smoothed. What say you guys?




Here is a video:


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RicinYakima posted this 1 weeks ago

My guesses, and only guesses, are the bolt face or excess extractor pressure on the top of the rim. You could also try a dummy cartridge at minimum length. FWIW 

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Aaron posted this 1 weeks ago

 It is with a very red face, bright red face, that I report the fix to this problem. I made up a new dummy cartridge and applied an even stronger crimp to the case. Problem solved. It was the crimp not being deep enough. So much for the fingernail test!

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  • Ken Campbell Iowa
Ken Campbell Iowa posted this 1 weeks ago

??? ...   so the front of the case neck was catching on the entrance to the chamber ?? ....

as in a similar cure would be to outside diameter  chamfer the case necks ?? 

if so i would consider chamfering the chamber entrance a little .. guessing 0.005 to 0.010 chamfer would do it.  starting with the 0.005 of course.  i think that would not affect safety at all, you are still on the solid part of the case head.

those 38-55 94s are quite the gun, a bud has a few of them, for sure all you need for white tails .  the Lee mold works great in his.


oh, oal isn't everything in feeding ... also the nose radius and ogive .

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Aaron posted this 1 weeks ago

That crimp on the bottom allows feeding. Looks like it was put there with a Lee "Factory Crimp" tool but it is the crimp in the Lyman seating/crimping die. I still am not happy with that Six O'clock lip on the chamber. I am determined to break that edge. Problem is the tool to use right? I think I will start with a dowel and 320 grit paper on it to knock the edge off it.

That Lee bullet is the ticket. The ogive duplicates the period bullets pretty well too. It carries enough SPG too. This cartridge, like the 45-90 in my 1886 will be a fussy little beast I am sure. Bullet selection for the 1886 is limited as you probably know but the 330gr Express Bullet (Lyman) really performs in that gun! With 20:1 alloy and 1600 fps, it mushrooms beautifully when pushed with holy black.

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Qc Pistolero posted this 6 days ago

You don't have to be ashamed(or red faced).It could happen to any of us.Thanks for sharing.One more thing to put in my bag of experience.

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