Can a Winchester .375 H&H model 70 Safari Expess be bored,rifled, and chambered to .404 Jeffery?? Plenty of barrel as it is also chambered in .458 with same contour. Looks like the chamber and throats would clean up and OAL of cartridges seem compatible. Feeding???

It can be done. Easy way is to rebarrel a RUM.

It can be done, but RyanBs suggestion is the best way to do it.

I already own the .375.

Cheaper to sell the 375 and buy a RUM. Significant costs with converting the H&H to the Jeffery.

Action costs, mag box, follower and floorplate. And the cost of making it feed.

Also, not sure who would rebore, I was looking for someone to do it for me.

thread below

http://forums.accuratereloadin...621015222#1621015222

quote:

Originally posted by Rockdoc:
Cheaper to sell the 375 and buy a RUM. Significant costs with converting the H&H to the Jeffery.

Action costs, mag box, follower and floorplate. And the cost of making it feed.

Is the Ultra Mag closer to the 404J than a 416 Rem Mag? Lots of those in Winchester M70's at a good price.

Ultra Mag based on 404J.

May be just a rebarrel. I have enquired here in Aus but no Mod 70 UM's were shipped here. Have thought about importing one for a 404J.

Others on here have made the conversion.

quote:

Originally posted by A7Dave:

quote:

Originally posted by Rockdoc:
Cheaper to sell the 375 and buy a RUM. Significant costs with converting the H&H to the Jeffery.

Action costs, mag box, follower and floorplate. And the cost of making it feed.

Is the Ultra Mag closer to the 404J than a 416 Rem Mag? Lots of those in Winchester M70's at a good price.

Interesting point about trying the feeding of 404 Jeffery through the .416 RemMag M70.
I never tried it, but now I got to.
Might be closer to feeding 404J than with a .375 H&H M70, might be little different?
Will check.

Definitely the easy way to go is to find an M70 RUM action and get the proper barrel and stock of your choice.
You can certainly rebore a .375 H&H barrel as long as you have about .700" diameter at the 24" muzzle diameter.
But that involves some time and expense and more uncertainty. Altogether more worthwile to rebarrel.
You need boltface work and feedrail work and magazine box work.
And not every gunsmith is going to be able to do it right.
The M70 RUM action that feeds 300 RUM is a no-brainer.
I bought one new, and found two others on the used-gun racks at Gander Mountain stores here and there, back when they were a going concern.
If Winchester ever makes more, sign me up for another, for a .410/404 Jeffery Justified,
to go with a .410/404 Jeffery Rimless Nitro Express CZ.

Comments on three M70-RUM-actioned rifles follow:



Above is a not-for-extended-pinky-finger-admiration, plain-ol' 404 Jeffery,
done with a #4 McGowen sporter, 24" long, 0.700" muzzle diameter.
Stock is a standard-weight (not a "Pounder") Brown Precision, re-manufactured by me.
It used to fit a .308 WCF M70 short action.
It has a lot of internal steel crossbolts, pillars, and JB Weld epoxy inside and outside.
Rifle weighs 8 lbs and 8 oz, bare and empty.
Since that is a .425-grooved barrel, this might be considered a .425/404 Jeffery.
Still does great work with all .423-caliber bullets, high velocity and low pressure with Varget and RL-15, not so good with slower powders.
Maybe the looseness of the bore is compensated by the tightness of the 1:10" twist?
This rifle is almost idiot-proof for handloading.
I could fix that by getting custom .425-caliber bullets and re-throating to a .426" diameter free-bore diameter.
The extra free-bore added to this standard 404 Jeffery chamber was only .424" diameter, so I cannot use .425-caliber bullets ... yet.

I recommend to anyone building a 404 Jeffery: Add some extra throat. The standard C.I.P. throat is just a narrow leade with zero parallel-sided free-bore.



Above is a .416 Dakota, a chrome-moly M70-RUM action with a stainless floorplate harvested from the rifle that got a Sunnyhill (below).
A Douglas #5 sporter of 1:12" twist was used for this, finished at 24" barrel length with muzzle diameter of 0.720".
HS Precision stock, with aluminum bedding block.
Weight of rifle is 8 lbs and 7 oz.



Finally, McMillan and Sunnyhill combo stock and floorplate were used on the M70-RUM action above.
The windowed RUM magazine box and follower and spring were retained from the original 300 RUM rifle,
though "windows were enlarged" for the .338 Lapua Magnum Improved necked to .500-caliber.
Barrel is a Pac-Nor #6 sporter, 24" length, 0.785" diameter at muzzle.
Weight is 9 lbs and 3 oz, with hidden steel crossbolts and pillars added to the McMillan "Magnum Fill" stock.



The "49-10" above is a 3 + 1 fourshooter.
If the boltface had not been opened up for the Rigby casehead, it could have been re-barreled to become a 4 + 1 fiveshooter as a 404 Jeffery.
The other two rifles above (404 Jeffery and .416 Dakota) are 3 + 1 fourshooters, with the standard M70-RUM bottom metal.

There is more than one way to skin a wildcat.
Riflecrank Incurable Permanente

Nice rifles there RIP!

Thanks, Rockdoc.
Usually with my rifles, only their mother could love them.
At least posting the above got me to measure a muzzle and weigh a rifle, on that .416 Dakota, after all these years ...
Now gotta go dig out a .416 RemMag and look at it.
Whatever, it will not be as slick as a RUM.

There is more than one way to skin a wildcat.
Riflecrank Incurable Permanente

By switching the 404J M70 bolt into the .416 Remington M70 and a .375 Weatherby M70, found some things of interest.

Here is the contour of the left feedrail on the M70 RUM action that feeds .416 Dakota, and is even slicker with 404 Jeffery,
less shoulder crowding, better feeding.
This action also has a windowed box which gives more shoulder room in the staggered stack,
and a flat-bottomed follower spring, with no space killing hump at the bottom rear of the spring.
Notice the left-side feed rails, biggest difference amongst the three M70 amigos:



I believe the above good feeder (.416 Dakota and 404 Jeffery) is just as it came from the factory, regarding feeding,
other than some polishing of the feed ramp.

Here is the .416 Remington, also just as it came from the factory. It works with .416 Remington. But it will not even retain 404 Jeffery ammo.
Three cartridges will go into the box, too tight to close on a 4th in the chamber with 3 in the box.
It is thus a 2 + 1 threeshooter. But if you bump the bolt, all three cartridges may fly out of it.
Or one cartridge might jump in early as the bolt is closed, and when it is ejected, two cartridges will eject,
one from the chamber followed almost simultaneously by a second one from the box:



Notice the rear part of the left rail is cut way back, compared to the 300RUM/404J/.416D-feeder.

And a great surprise is that my .375 Weatherby M70 will retain 404 Jeffery cartridges and feeds pretty smoothly,
though also tight with 3 down in the box, a 2 + 1 three-shooter.
It might make a serviceable 404 Jeffery if a windowed box is used, and maybe some experimentation with followers.
Of course the space-killing hump-bottom spring has been replaced with a M98 Mauser spring from Brownells,
and it is a good 3 + 1 fourshooter as a .375 Weatherby,
simply rechambered from .375 H&H, M70 Classic.
The feed rails may have been whittled on a bit:





This anecdote has been brought here, for what it is worth.
My factory .416 Remington M70 seems to be past turning into a 404 Jeffery. Left rear rail has been cut away too much.
The .375 H&H M70 might be a better candidate for a 404 Jeffery, 3 + 1 fourshooter.
Make it a 4 + 1 fiveshooter with the Sunnyhill-McMillan drop floorplate and stock with windowed RUM box.
Or maybe one of the Wiebe XRM boxes would add enough to the standard M70 stock and floorplate combo to make it into a fourshooter, 3 + 1, 404 Jeffery, re-barreling is smarter.
Or a .375/404 Jeffery (have to re-barrel or set back the factory barrel of a .375H&H).
Or a .410/404 Jeffery Rimless Nitro Express: Rebarrel with a Douglas .410-grooved barrel.
That will feed slicker than even the 404 Jeffery.
Duane Wiebe may have quit making those XRM boxes?
I have one left to try in the .375 Weatherby.
I used the only other one I have to turn my fiveshooter 400 Whelen into a sixshooter.
Brownells might have some RUM bottom metal?

There is more than one way to skin a wildcat.
Riflecrank Incurable Permanente

Look closer Jim.
There is not enough rear left rail left on the .416 Remington to do as you say.
A windowed box probably would not keep a 404 Jeffery from auto-ejecting.
They are popping free too soon at the ass end of the box ...

Well, I should have quoted Jim for discussion purposes. His comment is gone.
Mighty quick on the quote, comment, and delete, eh, Jim?

There is more than one way to skin a wildcat.
Riflecrank Incurable Permanente

Ron, Were the rails also modified on your Lapua based 12.8x68 Magnum?

quote:

Originally posted by RIP:
Look closer Jim.
There is not enough rear left rail left on the .416 Remington to do as you say.
A windowed box probably would not keep a 404 Jeffery from auto-ejecting.
They are popping free too soon at the ass end of the box ...

Well, I should have quoted Jim for discussion purposes. His comment is gone.
Mighty quick on the quote, comment, and delete, eh, Jim?

There is more than one way to skin a wildcat.
Riflecrank Incurable Permanente

Yep I deleted the post and was going to replace with an edited post... Boiled it down to my above posted question instead...

quote:

Originally posted by capoward:
Ron, Were the rails also modified on your Lapua based 12.8x68 Magnum?

Yes, they are different, more like on the .375 Weatherby above. I'll take more pictures later, for another anecdote, but right now I gotta go have a life.

There is more than one way to skin a wildcat.
Riflecrank Incurable Permanente

Yes I did look closer at the photos just before I deleted my post...

And here's what I intended to re-post:
I had a number of discussions with a custom gunsmith and with my metal smith (before he retired) regarding modifications required to the M70 action for the 375 Ruger based cartridges.

Main pearl of wisdom was - it would be less difficult to modify the bolt face, rails, and magazine (where required also the bolt stop a ejector) of a M70 LA factory chambered in 25-06 to properly feed the 375/416 Ruger cartridges than to use any standard length belted cartridge action (totally hit and miss with these due to the existing factory rail cuts). Any of the 03/06 factory based actions were usable for cartridges of larger diameter than the 375/416 Ruger cartridges.

This is why the 404-375 exists

quote:

Originally posted by boom stick:
This is why the 404-375 exists

Very good reason! The only downside right now is a reliable source for barrel re-boring...