Currently available way to get a 4 round magazine Winchester 70 375 H&H

[MaxM25]

I have read about the Duane Weibe XRM magazine box that was available for the Winchester 70 in 375 H&H. Unfortunately, it does not seem to be available anymore. Is there anyway that is currently available to increase the magazine capacity? I read something about changing the magazine spring to one without a hump using Winchester P/N U356420930 Magazine Spring L/A; does that work? It really seems a shame that the XRM stopped being available.

 

[nomspc]

I have read about the Duane Weibe XRM magazine box that was available for the Winchester 70 in 375 H&H. Unfortunately, it does not seem to be available anymore. Is there anyway that is currently available to increase the magazine capacity? I read something about changing the magazine spring to one without a hump using Winchester P/N U356420930 Magazine Spring L/A; does that work? It really seems a shame that the XRM stopped being available.

Jim Brockman, http://www.brockmansrifles.com/index.php has made a few extended Model 70 magazine floor plates for me.

 

[odonata]

I know nothing about this company or the product. I'm just sharing a link:

Sunny Hill Enterprises - 70 Winchester

 

[MaxM25]

I thought it was interesting that there is mention of a spring and follower change that can get a 4th round of 375 H&H in the magazine.

It looks like that bottom metal had an Oberndorf release. Is there anyway pro/con to that style compared to the push button on the Winchester from the factory?

 

[Philip Glass]

Whatever you decide to do just make sure that it works very well before going on a DG hunt with it. These kind of modifications scare me so just be careful.

 

[MaxM25]

Jim Brockman, http://www.brockmansrifles.com/index.php has made a few extended Model 70 magazine floor plates for me.

View attachment 647766

That is great.

 

[Ontario Hunter]

When I ordered bottom metal for my 404 build on 98 Mauser, Swift-Blackburn offered both 3+1 and "extended" 4+1. But it is my understanding that 4+1 requires custom stock. It will not drop into a standard 98 Mauser stock. I went with 3+1 because I didn't want to wait for a custom stock to be made. If I can't stop a buffalo with four rounds of 400 gr 404 Jeffery, perhaps I deserve to get stomped. Anyway, I modified the extractor to snap over on a round dropped in an empty chamber so fifth round can still be loaded quickly if needed.

 

[MaxM25]

I know nothing about this company or the product. I'm just sharing a link:

Sunny Hill Enterprises - 70 Winchester

View attachment 647768

That Model 640 bottom metal looks interesting. It seems to have an Oberndorf release. Is the Oberndorf release for the magazine an OK thing to have on a dangerous game rifle?

 

[Ontario Hunter]

That Model 640 bottom metal looks interesting. It seems to have an Oberndorf release. Is the Oberndorf release for the magazine an OK thing to have on a dangerous game rifle?

The Oberndorf style was all I could find when I was shopping for 416 Rem bottom metal when building my 404J (Sunny Hill would make 404J bottom metal for me but $700 pricetag was too much). I don't think it's that big an issue if the release is stiff enough. Some makers sell them with adjustable release. Mine from Swift-Blackburn required some fine tuning. Any hunter holding a 375 so loosely that his finger hits the release during firing will probably have other issues to worry about. Like scope or thumb hitting him in the face. I don't see accidentally releasing the floorplate being much concern if you spend some time learning to shoot your gun.

Again, note that the magazine box is deeper on NECG Model 640. It will hang below your current stock. If the floorplate is wider than the magazine, and most are to conceal the contact area around the magazine box, then that would be a problem for you. Besides being unsightly, the exposed floorplate overhang could get caught on stuff. It is hard to tell from the photo if the edge of floorplate is flush to the sides of magazine but I seriously doubt it. If not, then a custom stock with deeper mag well would be required.

 

[odonata]

I cannot give you an opinion based on in-field experience because I've never been DG hunting. Any reply I give will be based totally on intuition.

Whenever I look at classic African rifles at places like Griffin & Howe or Westley Richards, this type of release is often seen on the bottom metal. There is currently an active thread on building a large 50 caliber rifle where pictures of the Weibe bottom metal shows that it uses this type of release as well. The main thing you would want the release to do is not move under heavy recoil and spill all of your backup rounds of ammo all over the dirt while you have something big & irritated heading directly for you. As mentioned above, the strength of the spring release being stiff enough is the main factor.

Compared to other "inside the bow" releases I've seen, this one looks similar & pretty substantial. But how it works & fits is unknown to me:

My expertise is mainly on how to use Google well to find stuff not rifle building.

 

[MaxM25]

The Oberndorf style was all I could find when I was shopping for 416 Rem bottom metal when building my 404J (Sunny Hill would make 404J bottom metal for me but $700 pricetag was too much). I don't think it's that big an issue if the release is stiff enough. Some makers sell them with adjustable release. Mine from Swift-Blackburn required some fine tuning. Any hunter holding a 375 so loosely that his finger hits the release during firing will probably have other issues to worry about. Like scope or thumb hitting him in the face. I don't see accidentally releasing the floorplate being much concern if you spend some time learning to shoot your gun.

Again, note that the magazine box is deeper on NECG Model 640. It will hang below your current stock. If the floorplate is wider than the magazine, and most are to conceal the contact area around the magazine box, then that would be a problem for you. Besides being unsightly, the exposed floorplate overhang could get caught on stuff. It is hard to tell from the photo if the edge of floorplate is flush to the sides of magazine but I seriously doubt it. If not, then a custom stock with deeper mag well would be required.

Yes, it seems the McMillan Safari stock is setup for this dropped magazine Sunnyhill.

https://mcmillanusa.com/shop/browse-mcmillan-rifle-stock-models/flat-top-only-stock-models/winchester-safari-flat-top/

 

[MaxM25]

It would be perfect to get a Duane Weibe XRM magazine box that allows an extra round in a Winchester. It is unfortunate that he stopped making them.

 

[Challer]

I used the Sunny Hill model 70 McMillan setup with great success

 

[Ontario Hunter]

You should explore the modified follower and spring method further. Very intriguing. Sounds like something a good machinist would be able to tackle.

 

[Ontario Hunter]

I used the Sunny Hill model 70 McMillan setup with great success

Can you supply a photo? I'm curious, does the magazine extend below the stock?

 

[Jack Stevens]

The magazine of my old BRNO 602, a Lon Paul custom, can hold six (6) .375 rounds, although typically I run it 5+1 so as not to stress the mag spring.

 

[cajunchefray]

That Model 640 bottom metal looks interesting. It seems to have an Oberndorf release. Is the Oberndorf release for the magazine an OK thing to have on a dangerous game rifle?

Do you have a Pre-64 made Model 70, or a post 1994 Model 70?

The Sunny Hill model 640 is for the Models 70s built prior to 1964, and the bottom metal, as pictured, is one piece magazine box and floorplate, a la Mauser 98.

The post 1994 made guns (marked "Classic" on the barrel), utilize a separate magazine box from the floorplate.

The Sunny Hill model 740 is correct for this. Personally, I prefer the classic look of the Oberndorf floorplate release. I have a Williams made floorplate on my M70 Classic 30-06, Oberndorf release and have had no problems.

Personally, I would not just change the follower and magazine spring to get a 4th round. The geometry of the follower, spring and mag box are designed to insure proper feeding. Not a chance I am willing to take.

I bought a recent production, used M70 Alaskan, 375 H&H for an (almost) too good to be true price on GB. It would not feed the 2nd and 3rd round worth a damn. I removed the bottom metal and found that the magazine spring was slightly kinked, out of alignment. A new spring from Winchester, of proper dimension, and it feeds perfectly.

 

[Challer]

Can you supply a photo? I'm curious, does the magazine extend below the stock?

Slightly. Now sold I went to the dark side of the R8

 

[Ontario Hunter]

Do you have a Pre-64 made Model 70, or a post 1994 Model 70?

The Sunny Hill model 640 is for the Models 70s built prior to 1964, and the bottom metal, as pictured, is one piece magazine box and floorplate, a la Mauser 98.

The post 1994 made guns (marked "Classic" on the barrel), utilize a separate magazine box from the floorplate.

The Sunny Hill model 740 is correct for this. Personally, I prefer the classic look of the Oberndorf floorplate release. I have a Williams made floorplate on my M70 Classic 30-06, Oberndorf release and have had no problems.

Personally, I would not just change the follower and magazine spring to get a 4th round. The geometry of the follower, spring and mag box are designed to insure proper feeding. Not a chance I am willing to take.

I bought a recent production, used M70 Alaskan, 375 H&H for an (almost) too good to be true price on GB. It would not feed the 2nd and 3rd round worth a damn. I removed the bottom metal and found that the magazine spring was slightly kinked, out of alignment. A new spring from Winchester, of proper dimension, and it feeds perfectly.

You are incorrect. The Sunny Hill Model 640 is not one piece bottom metal and floorplate. The hinge pin through the trigger guard for Oberndorf floorplate release is clearly visible in the photographs. Also, Model 98 Mauser has two piece floorplate and bottom metal. But the floorplate release is recessed push button ahead of the trigger guard and floorplate is not hinged on 98 Mauser. It can be released and removed.

I also had problems with magazine spring when I built my 404J. New 416 Rem bottom metal was of course substantially longer than original 98 Mauser 8mm. Many doing this build simply use the 8mm follower in the longer box. I guess it works. But New England Custom Gun sells longer magnum followers for 98 Mauser so I bought one. The shorter follower would be unsightly, allow dirt etc to fall past the end of follower (admittedly not a big deal for hinged floorplate magazine), and possibly poor feeding/jamming due to tipping of narrower/shorter follower inside larger mag box. Longer and wider NECG follower allows for custom fit side to side. Tabs front and back on left side can be trimmed as needed. And of course length can be cut back if needed. I had to trim the forward tab and just a bit from the corners to make it work consistently in my build. Easier than removing more metal from feeding port in receiver. But I was still having issues with the follower becoming fouled in the box. Problem was military 8mm Mauser follower spring is tapered down in width at the end that locks into follower. NECG follower is designed with spring slot and keepers for spring that is not tapered in width. The spring kept slipping cockeyed on the follower causing it to tilt and catch on magazine walls. Magnum Mauser springs are apparently full width throughout but no one sells them anymore (except maybe Mauser = $$$$!). I tried reversing the spring so full width end snapped into follower. That just shifted the problem to floorplate. Solution: carefully squeeze both sides of the follower in a vice at the point where the spring keepers are located. Hey, if it didn't work, I could always fall back on the military keeper. But it did work. And the deformity is barely noticeable (although the deformity from carving into follower to adjust for proper feeding of second round in magazine is quite visible - but who cares, it works!). The squeezed point is visible on the lip of follower about 2/3 way to front. This photo was taken before final polishing. The carved out portion is now not so obscene.

 

[cajunchefray]

You are incorrect. The Sunny Hill Model 640 is not one piece bottom metal and floorplate. The hinge pin through the trigger guard for Oberndorf floorplate release is clearly visible in the photographs. Also, Model 98 Mauser has two piece floorplate and bottom metal. But the floorplate release is recessed push button ahead of the trigger guard and floorplate is not hinged on 98 Mauser. It can be released and removed.

I also had problems with magazine spring when I built my 404J. New 416 Rem bottom metal was of course substantially longer than original 98 Mauser 8mm. Many doing this build simply use the 8mm follower in the longer box. I guess it works. But New England Custom Gun sells longer magnum followers for 98 Mauser so I bought one. The shorter follower would be unsightly, allow dirt etc to fall past the end of follower (admittedly not a big deal for hinged floorplate magazine), and possibly poor feeding/jamming due to tipping of narrower/shorter follower inside larger mag box. Longer and wider NECG follower allows for custom fit side to side. Tabs front and back on left side can be trimmed as needed. And of course length can be cut back if needed. I had to trim the forward tab and just a bit from the corners to make it work consistently in my build. Easier than removing more metal from feeding port in receiver. But I was still having issues with the follower becoming fouled in the box. Problem was military 8mm Mauser follower spring is tapered down in width at the end that locks into follower. NECG follower is designed with spring slot and keepers for spring that is not tapered in width. The spring kept slipping cockeyed on the follower causing it to tilt and catch on magazine walls. Magnum Mauser springs are apparently full width throughout but no one sells them anymore (except maybe Mauser = $$$$!). I tried reversing the spring so full width end snapped into follower. That just shifted the problem to floorplate. Solution: carefully squeeze both sides of the follower in a vice at the point where the spring keepers are located. Hey, if it didn't work, I could always fall back on the military keeper. But it did work. And the deformity is barely noticeable (although the deformity from carving into follower to adjust for proper feeding of second round in magazine is quite visible - but who cares, it works!). The squeezed point is visible on the lip of follower about 2/3 way to front. This photo was taken before final polishing. The carved out portion is now not so obscene.
View attachment 647952

Well, I misstated the obvious: If we are talking about Oberndorf bottom metal, then I assumed (we know how that goes), that a reader would understand the mechanism, with the hinged floorplate that opens and swings down.

The point is Pre-64 use an integral magazine box, properly dimensioned for the cartridge(s), and the feed rails of the action correspondently dimensioned for proper feeding (a la M98).
Post 1994 Classics use a separate magazine box, that dimensions determine the feeding for the cartridge(s).

Interesting about the NECG Magnum follower and trimming to work with .404 Jeffery.
I bought one for an Interarms Whitworth .375 H&H, that was not feeding properly. That and a new magazine spring, problem solved.