Home Forums Hunting & Shooting Express Rifles and Big Bores Only Winchester 70 458 build

For Sir Joe and anyone else interested:











Supplementary views:







XRM: "Extra Round Magazine" for Winchester M70 Classic.
The XRM box is not much bigger, but it did allow me to get an extra cartridge into a rifle
and close the bolt over it, for both a .400 Whelen-B and a .458 WM+ with 3.6" COL.
No need to restock with a drop belly stock and drop magazine
like with a Sunny Hill-McMillan combo which allows only one extra cartridge also.

Nicely done. Thanks for taking the time!

Let me add to this, as I stated previously on the .458 thread that I converted a Model 70 .458 Super Grade to .416 Remington with the magazine changed out to accommodate longer cartridges by having a 95mm internal OAL capacity fitted and even those longer than factory spec cartridges loaded and ejected fine with no changes to the action opening whatsoever so, as Ron has stated, the .458/.30/06 action was left intact. It is not complicated and it is reliable, which is the main objective with dangerous game cartridges.

John

AKwolverine,

Welcome. My pleasure. It is for my understanding too.
I never took the time previously to note how little size difference there is
between the unblocked-standard M70 mag box and the Wiebe XRM.
If the standard box is tight with 3 down, it will be tight for getting 4 down with the XRM.
Cartridges fatter in the shoulder area will be tighter.
The .375 H&H ought never be a problem.
Heck, the Pre-'64 M70 mag box holds 4 down with the factory standard .375 H&H sheet metal box.

HEAR, ALL YE GOOD PEOPLE,
hear what this brilliant and eloquent speaker has to say !


Except for the part about rebarreling a .458 WM to a .416 RM. Tisk tisk.

So, Sir Woods had a magazine box inside length of 95mm or about 3.75", .416 Rigby length, and the M70 Classic action ejected that COL.
Superb.
Winchester actually made a few .416 Rigby rifles on the M70 Classic action:
2001, one year production for the MODEL 70 CLASSIC CUSTOM AFRICAN EXPRESS .416 Rigby.

I have a windowed M70 Classic magazine box that is 3.85" inside the box,
ordered it from Brownells years ago.
Now there is an idea for converting an M70 Classic that already has the rear bridge milled for the .375 H&H pattern receiver.
I am going to sleep on it first.

Sir Ron,

Thanks for taking the time to do the detailed description with illustrations and measurements.

Great work and very useful info.

Welcome, Sir Joe.
Then there is the Pre-'64 Win M70 mag box for .375 H&H
that is 4+1 for that cart,
and probably one of the few mags that is "Mauser Cosine" perfect
for its application,
on a true .30-06 action length, opened up.

All very useful and a pleasure to read.

I have a semi-Frankenstein 375 H&H, M70 New Haven Classic stainless.

A New Haven Classic 7mm Remington mag/ 338 Winchester/ 300 Winchester mag action, with the ejector blade shortened and magazine block removed; with a 375 H&H New Haven Classic stainless barrel fitted. Original cartridge unknown, I bought as is, without looking at the rifle closely. I certainly noticed when I went to install rear scope base.
Appears, through redneck tape measure use, there is about 1/4” more action opening on a factory 375 H&H New Haven Classic.

With that said, this rifle feeds 375 H&H factory loads fine. The only advantage that I can reach for with the 375 H&H factory action, is that extra 1/4” action opening gives a little more room for loading the magazine.

I rather like that Winchester M70 Classic or FN Frankenstein look.
The action is longer overall than the Pre-'64 M70 African .458 WM or .375 H&H Alaskan action,
yet retains that long rear bridge.
Africanized, or Africansteined, one might say.

That longer rear bridge with wider hole spacing and more rear scope base contact for J-B-Welding does not hurt strength.
I always load by pushing the cartridges into the rear of the magazine, and find no impediment with the uncut port,
which obviously is long enough to handle 3.600" COL, for ejecting unfired rounds.
Yep, I prefer the Africansteined M70 Classic & FN for a .458 WM+
with which to open a can of whoop ass on the SAAMI .458 Lott.

I know sacrilegious, but I ran some 458 Lott, 500 grain factory loads through the action. Fed fine, up to the chamber restriction. No issue on the ejection of these either.
Agree on the habit of pushing cartridges to the rear when loading.