Question for Real M-70 Smith's

[INTJ]

I know I rarely post anymore. No time. I am now the Director of Operations. I also don't have to do any chambering or threading for customers. I do get to chamber my own stuff at home, which I enjoy.

I recently built a 30-28 Nosler on a CRF M-70 Classic. I opened up the action to run a Wyatt's 3.825" inside length box and then chambered the barrel. Everything came out great.

I thought I was doing the right thing by using an M-70 that was originally a 300 RUM. Well, not so much.

The M-70 RUM action has a cutout in the left feed rail, about in the middle. It corresponds to a protrusion in the follower.

The rifle won't feed the cases from the left side. It works great from the right side. On the left side, as soon as the case shoulder gets to the cutout it pops up.

This isn't an issue with the non-RUM
actions. I also have a 33-28 Nosler I built on an M-70 338 action, also with the Wyatt's box, and it feeds so well that I thought about barreling it into a DG cartridge. The non-RUM actions have no cutout in that left side feed rail.

Has anyone ever found a fix for this cutout on the M-70 RUM actions when long Wyatt's boxes are installed?

 

[kendog]

I know I rarely post anymore. No time. I am now the Director of Operations. I also don't have to do any chambering or threading for customers. I do get to chamber my own stuff at home, which I enjoy.

I recently built a 30-28 Nosler on a CRF M-70 Classic. I opened up the action to run a Wyatt's 3.825" inside length box and then chambered the barrel. Everything came out great.

I thought I was doing the right thing by using an M-70 that was originally a 300 RUM. Well, not so much.

The M-70 RUM action has a cutout in the left feed rail, about in the middle. It corresponds to a protrusion in the follower.

The rifle won't feed the cases from the left side. It works great from the right side. On the left side, as soon as the case shoulder gets to the cutout it pops up.

This isn't an issue with the non-RUM
actions. I also have a 33-28 Nosler I built on an M-70 338 action, also with the Wyatt's box, and it feeds so well that I thought about barreling it into a DG cartridge. The non-RUM actions have no cutout in that left side feed rail.

Has anyone ever found a fix for this cutout on the M-70 RUM actions when long Wyatt's boxes are installed?

I cannot answer your question, but I can sure tell you for certain that getting rounds to feed from a receiver designed around a different cartridge can cause all kinds of gray hair and heartache. Of all things riflesmithing, this is an area where angels fear to tread.

 

[INTJ]

I cannot answer your question, but I can sure tell you for certain that getting rounds to feed from a receiver designed around a different cartridge can cause all kinds of gray hair and heartache. Of all things riflesmithing, this is an area where angels fear to tread.

One you do it a few times it isn't that bad. Aside from have it someone tig weld the rail back--then milling it smooth, or making my own mag box--don't have the sheet metal tools, I can't think of a solution

 

[CCM]

Can you post a photo or 2?

Does the Wyatt's box allow the cartridges to sit far enough outboard? If there isn't enough friction on the bottom side of the feed lips it can make the cartridges pop prematurely.

Also, have you looked into center feed?

 

[INTJ]

Can you post a photo or 2?

Does the Wyatt's box allow the cartridges to sit far enough outboard? If there isn't enough friction on the bottom side of the feed lips it can make the cartridges pop prematurely.

Also, have you looked into center feed?

The width is fine. I have looked into center feed. No one really makes an extended center feed box for an M-70, at least that I can find. I have tried a 3.8" center feed box for a 700. It almost works, but the bent-in sheet metal center feed lips at the top of the magazine interferes with the anti-bind cut on the M-70 bolt. I might be able to make an offset center feed by bending those center feed lips.

However, it feeds perfectly from the right side. If that left side cutout wasn't there it would feed perfectly. The issue is the shorter 28 Nosler cases, when pushed another .200" back in the extended mag box, pop up when the shoulder hits the left rail cutout. With full length 300 RUM cases in a standard length mag box this isn't an issue.

 

[X Count]

The action will warp TIG welding on one side. What about welding and extension to the mag box that protrudes up into that area, effectively blocking that gap without modifying the action itself?

 

[INTJ]

The action will warp TIG welding on one side. What about welding and extension to the mag box that protrudes up into that area, effectively blocking that gap without modifying the action itself?

That has been my latest thought. Take a mag box and silver solder a piece to function as a rail in the cutout.

 

[Fast14riot]

Yeah, for a stagger feed I'd look into shimming the inside of the box on that side. At the very least above the follower with one round (last round) loaded.

 

[X Count]

Yep and you can re work it as much as you need without harming the action.

 

[AlNyhus]

I'd either epoxy a piece on the underside of the feed rail cut out or bend a 90 degree piece and epoxy it to the outside of the mag box. No reason that wouldn't work. -Al

 

[Bill K]

Safest way to probably solve this issue and not harm the receiver would be to alter the magazine as some suggest, which will probably work just fine.

 

[INTJ]

I'd either epoxy a piece on the underside of the feed rail cut out or bend a 90 degree piece and epoxy it to the outside of the mag box. No reason that wouldn't work. -Al

I didn't think about putting a strip underneath the whole feed rail. That should work well.

 

[Jonnyofalltrades]

Solder in a slip of steel to make up that slot. Low temp silver solder won't even discolor the surrounding metal.
That's what I would do, anyway.

 

[CCM]

I didn't think about putting a strip underneath the whole feed rail. That should work well.

I just got on to suggest the same. I think epoxy would be a whole lot easier than trying to solder on a thin piece of metal.

 

[eddief]

I thought the same as Al, but I would JB quick a piece of spring steel on the bottom of the rail to test. If it works, you could then have the piece laser welded in spot.

 

[kendog]

One you do it a few times it isn't that bad. ...

Except for this one...

Let me get some popcorn.

 

[mace2364]

a little different, but I had an issue what you’re having on a Pre-64 M70 that a customer had me do some modifications on. It was a fairly significant change and the follower was binding the cartridges as they got into the receive. Different cause, in that there was no cutout there like yours. Anyway, after I messed with it for a while, I discovered that if I put some shims on the inside of the mag box, it would feed how it was supposed to. I just epoxied them, as when the rifle is assembled the follower and cartridges would help hold them in place.

 

[Machinist John]

Hey Blaine, I will send pics via Text in a few minutes for a solution. Think wide and long!

John

 

[Sniperhandle]

The width is fine. I have looked into center feed. No one really makes an extended center feed box for an M-70, at least that I can find. I have tried a 3.8" center feed box for a 700. It almost works, but the bent-in sheet metal center feed lips at the top of the magazine interferes with the anti-bind cut on the M-70 bolt. I might be able to make an offset center feed by bending those center feed lips.

However, it feeds perfectly from the right side. If that left side cutout wasn't there it would feed perfectly. The issue is the shorter 28 Nosler cases, when pushed another .200" back in the extended mag box, pop up when the shoulder hits the left rail cutout. With full length 300 RUM cases in a standard length mag box this isn't an issue.


View attachment 1595624
View attachment 1595625

Looking at the action, Someone has opened up the rear of the action to accommodate for a long cartridge, It's possible this action was not originally for Ultra mag.

 

[Sniperhandle]

D'arcy Echols website has a lot of info and I have shared this before. Go on his blog, There are a lot of pics and a whole lot of useful info on converting bolt guns, Especially win mod 70's and Mauser 98's. This is just one sample, I have read most of the articles at one time or another. I wish I had his knowledge.

Converting a Pre- 64 Mod-70 action from 30-06 to 300 H&H Part 1

In the late eighties as I began to set up or build more 375 H&H's for hunters and finding suitable actions/rifles to do so could be a chall...

echolsrifles.blogspot.com