Feeding Issues, please help!

[Stuart Satterlee]

Frog Stealer,
I recently fixed a 404 Jeffery M-70 conversion rifle that had the exact same problem you are having with your rifle.
To fix it I cut the tabs off the of the magazine box, this modification to the box allows the bullet noses to spread out just enough so the cartridges will stay under the feed rails when the bolt is cycled back either forcefully or gently.
With the magazine box removed from your rifle you will see two vertical sheet metal tabs that project vertically. Use a dremmel tool with a cut off wheel and remove those tabs, debur the edges with a file and reassemble the rifle.
The rifle I fixed was done by some other Smith I can't recall his name at the moment, not that it matters much.
When looking at the M-70's there where three versions of the ultra mag actions, the main differences in them was how the feed rails where machined at Winchester. The first version had straight rails with out flared openings in the rails, the second had just one flare on the left side and the third had rail flares on both sides. The first version was the best action for doing a 404 because no flares means more rail metal which means the cartridges stay under
The rail until fed.

 

[frog stealer]

Frog Stealer,
I recently fixed a 404 Jeffery M-70 conversion rifle that had the exact same problem you are having with your rifle.
To fix it I cut the tabs off the of the magazine box, this modification to the box allows the bullet noses to spread out just enough so the cartridges will stay under the feed rails when the bolt is cycled back either forcefully or gently.
With the magazine box removed from your rifle you will see two vertical sheet metal tabs that project vertically. Use a dremmel tool with a cut off wheel and remove those tabs, debur the edges with a file and reassemble the rifle.
The rifle I fixed was done by some other Smith I can't recall his name at the moment, not that it matters much.
When looking at the M-70's there where three versions of the ultra mag actions, the main differences in them was how the feed rails where machined at Winchester. The first version had straight rails with out flared openings in the rails, the second had just one flare on the left side and the third had rail flares on both sides. The first version was the best action for doing a 404 because no flares means more rail metal which means the cartridges stay under
The rail until fed.

Stuart,

Thanks a bunch for this information. I will remove the box when I get home tonight and check it out!

 

[frog stealer]

Frog Stealer,
I recently fixed a 404 Jeffery M-70 conversion rifle that had the exact same problem you are having with your rifle.
To fix it I cut the tabs off the of the magazine box, this modification to the box allows the bullet noses to spread out just enough so the cartridges will stay under the feed rails when the bolt is cycled back either forcefully or gently.
With the magazine box removed from your rifle you will see two vertical sheet metal tabs that project vertically. Use a dremmel tool with a cut off wheel and remove those tabs, debur the edges with a file and reassemble the rifle.
The rifle I fixed was done by some other Smith I can't recall his name at the moment, not that it matters much.
When looking at the M-70's there where three versions of the ultra mag actions, the main differences in them was how the feed rails where machined at Winchester. The first version had straight rails with out flared openings in the rails, the second had just one flare on the left side and the third had rail flares on both sides. The first version was the best action for doing a 404 because no flares means more rail metal which means the cartridges stay under
The rail until fed.

Stuart,

Yesterday I had some time to work on the feeding issue with my rifle...I removed the vertical tabs like you suggested (I ground mine off with the dremel, as opposed to cut them out) and now my rifle feeds perfect! I loaded three dummy rounds and cycled them through the action fast and slow...I couldn't get them to fail! Thanks so much for your recommendation!

 

[Stuart Satterlee]

Frog stealer,
Good to hear. That's two M-70 404 Jeffery conversion rifles fixed that exhibited that problem and the beautiful thing is, it's such an easy fix.
Stuart Satterlee

 

[DHH45]

Frog Stealer,
I recently fixed a 404 Jeffery M-70 conversion rifle that had the exact same problem you are having with your rifle.
To fix it I cut the tabs off the of the magazine box, this modification to the box allows the bullet noses to spread out just enough so the cartridges will stay under the feed rails when the bolt is cycled back either forcefully or gently.
With the magazine box removed from your rifle you will see two vertical sheet metal tabs that project vertically. Use a dremmel tool with a cut off wheel and remove those tabs, debur the edges with a file and reassemble the rifle.
The rifle I fixed was done by some other Smith I can't recall his name at the moment, not that it matters much.
When looking at the M-70's there where three versions of the ultra mag actions, the main differences in them was how the feed rails where machined at Winchester. The first version had straight rails with out flared openings in the rails, the second had just one flare on the left side and the third had rail flares on both sides. The first version was the best action for doing a 404 because no flares means more rail metal which means the cartridges stay under
The rail until fed.

Stuart
having the same problem. Any pics of the vertical tab before I start removing metal
I have a Wea Mark V rebarred to 375 RUM

 

[Stuart Satterlee]

Stuart
having the same problem. Any pics of the vertical tab before I start removing metal
I have a Wea Mark V rebarred to 375 RUM

I'm not sure about Weatherby mag boxes vs Winchester mag boxes. How ever your problem exists because you've moved to a cartridge that has larger case dimensions than what your magazine box was designed for, say maybe a 300 Weatherby prior to rebarreling to 375 Rum.
My gut feeling here is we need to be able to spread your 375 Rum cartridge stack to enable the cartridges to stay under the rails until it's their turn for feed.
Get a Weatherby mag box for 30-378, 378, or 460 reason being those 3 are the biggest rounds going in a Mark v, the 375 Rum has similar needs from a magazine box, big and wide. What caliber was your Mark v prior to rebarrel.

 

[DHH45]

I'm not sure about Weatherby mag boxes vs Winchester mag boxes. How ever your problem exists because you've moved to a cartridge that has larger case dimensions than what your magazine box was designed for, say maybe a 300 Weatherby prior to rebarreling to 375 Rum.
My gut feeling here is we need to be able to spread your 375 Rum cartridge stack to enable the cartridges to stay under the rails until it's their turn for feed.
Get a Weatherby mag box for 30-378, 378, or 460 reason being those 3 are the biggest rounds going in a Mark v, the 375 Rum has similar needs from a magazine box, big and wide. What caliber was your Mark v prior to rebarrel.

It has been a 257,7mm Remington Mag I'veownedthisaction for 20-25 years. After rebarreling to the RUM I ordered a 378 drop box. I had to fold in the lips to keeping the 2nd round from popping out. It works but is still a little rough. I can live with it. Just not as smooth as I'd like.
Thanks

 

[Shootist43]

It is truly a small world. Sometime after this post was written I bought this rifle on / off Gunbroker not realizing its history. As frog stealer stated, it now junctions just fine. I posted an article about this rifle several years ago.

My Plain Jane has a Heart of Gold

My most recent acquisition was a Winchester that had been converted into a 404 Jeffery. Plain straight grain wood, no engraving and a barrel from a maker that I'd never heard of, assembled by a guy named Randy. The previous owner had all of the work done and I purchased the rifle as is off...

www.africahunting.com

 

[baxterb]

I'm not sure about Weatherby mag boxes vs Winchester mag boxes. How ever your problem exists because you've moved to a cartridge that has larger case dimensions than what your magazine box was designed for, say maybe a 300 Weatherby prior to rebarreling to 375 Rum.
My gut feeling here is we need to be able to spread your 375 Rum cartridge stack to enable the cartridges to stay under the rails until it's their turn for feed.
Get a Weatherby mag box for 30-378, 378, or 460 reason being those 3 are the biggest rounds going in a Mark v, the 375 Rum has similar needs from a magazine box, big and wide. What caliber was your Mark v prior to rebarrel.

I have a pic DArcy Echols sent me once of a 404 in a g33/40 dimension mag box. The front was so narrow that the front of the rounds would pinch together rather than lay correctly from front to back per Mausers rule. They would load in the mag very sketchily, but the second you bumped it, the rounds would eject. My guess is a lot of conversions to straighter cases are doing this for the same reason you state - too narrow for the case.