Lengthening a model 70 magazine

[Slimbo]

Looking to increase the mag box length in my M70 classic 300 winchester. I understand you can modify the mag box, but I'd like to get a purpose built box. What is everyone using, and where do you purchase them in canada?

 

[Magellann]

Wouldn't it be easier to just carry a second mag in your pocket? It seems like a lot of effort to carry an extra couple rounds, if it can even be done.

 

[unstableryan]

I'm thinking to increase the cartridge OAL, not to hold more ammo.

 

[Magellann]

Why would you need to increase the OAL unless you are switching the rifle to a different caliber. And then you just need to buy the correct caliber mag?

 

[nomad 68]

You're limited in mag length by the bottom metal.

 

[silverfoxdj]

I'm thinking to increase the cartridge OAL, not to hold more ammo.

Is this so your closer to the lands?

 

[Leeper]

You should be able to order the mag box for the 375 H&H. The ideal would be to try to get a mag box from D'Arcy Echols but there are some mods necessary to the receiver to use this box.

 

[unstableryan]

Yeah, or for case capacity reasons, if he’s shooting really heavy and long VLD Bullets, you don’t want to be limited by an overall length that was determined by whatever hunting Bullets were common at the time. Some of the heavy vld Bullets look like lawn darts

I found a better picture, but it was like 3000x4000 pixels so I found this one.

Is this so your closer to the lands?

 

[mbogo3]

Also a 7mm Rem mag re-chambered to 7 mm STW would require the same.

 

[BigUglyMan]

Wouldn't it be easier to just carry a second mag in your pocket? It seems like a lot of effort to carry an extra couple rounds, if it can even be done.

Length, not capacity.

Order a H&H-length mag box and follower and you're in business. You will have to modify the rear frame rails (they are radiused at the rear and need to be squared) and relieve the ejector so that rounds on the left side can ride all the way up against the feed rails. its not hard but if you're not handy any gunsmith can do it for you.

 

[silverfoxdj]

Yeah, or for case capacity reasons, if he’s shooting really heavy and long VLD Bullets, you don’t want to be limited by an overall length that was determined by whatever hunting Bullets were common at the time. Some of the heavy vld Bullets look like lawn darts

I found a better picture, but it was like 3000x4000 pixels so I found this one.

That makes sense...

 

[Dogleg]

Looking to increase the mag box length in my M70 classic 300 winchester. I understand you can modify the mag box, but I'd like to get a purpose built box. What is everyone using, and where do you purchase them in canada?

You can get the mag box for a .375, or take the spacer out. The follower for a .375 will be proper, but in reality the old one will probably work.

That gets you started but the next thing you come up against is the bolt stop has to be shortened or replaced so the bolt gets back to the new location. Shortening is easy but the part isn't that much. Next is the ejector which has to be modified or replaced. Its not all that hard to do if you like playing and grinding but it isn't something you want to pay someone by the hour to do.

You may or may not have to grind into the corners.

If you're still reading; the ejection port on the Express length M70 is 3.750 and the standard length is 3.100". That might or might not make any difference to function but you might want to consider that someone probably thought 5/8" mattered. If it turns out it does, you can scallop the rear action ring.That sort of thing used to be done when building on Mausers.

Western Gun Parts will have what you need, or Wyatt will have some even longer ones.

 

[Slimbo]

Thank you for all the info. Just got the rifle and its my first 300 win. I think ill wring it out a bit and see if I really even need more than 3.34''.