mod 70 .338 win to .340wby

[Boman]

Hey guys, I am thinking of buying a Winchester model 70 extreme weather (stainless) model in .338 win. But what I'd like to do is turn it into a .340wby. Besides the rechamber what else would need to be done? Thank you

 

[Cold Trigger Finger]

Is the action long enough?

 

[Boman]

Great question, how do I find out? The .338 win isn't much shorter I don't think

 

[Cold Trigger Finger]

The 340 is longer by over. .3" the old model 70 were all Long actions that had a magazine block for the standard and I believe short action cartridges. I don't know if the new ones are size specific actions or still a one size fits most.

 

[Boman]

Ok got it. I should measure the magazine box. I'll try calling winchester as well.

 

[Cold Trigger Finger]

Open the floor plate or take the barreled action out of the stock. You should be able to see. The standard length carts had a block in the magazine so they would hold the 3.4-.5" ammo correctly. I know the stainless 338 model 70 that I had did. It would have been an easy conversion to 340 . . I now wish I had done that. But hind sight is always 20/20 .

 

[MagnumManiac]

Sorry, but you'll need a 375 'magnum' length action for the 340 Weatherby, I know, I have one on a Model 70 S/S 'Classic' action.
I think you could buy a new 375 or 416 and have it made into a switch barrel, that's what I did.

Cheers.
gun)

 

[J E Custom]

Hey guys, I am thinking of buying a Winchester model 70 extreme weather (stainless) model in .338 win. But what I'd like to do is turn it into a .340wby. Besides the rechamber what else would need to be done? Thank you

The 338 RUM is almost the same length as the 338 WIN and might be a good replacement for it.

The 338 Win is 3.340 coal , and the 338 Rum is 3.350 Coal and does not have the belt and has more powder capacity than the 340 Weatherby.

Just a thought

J E CUSTOM

 

[Boman]

Ok well I can look at both options. I was looking at doing this with a kimber Montana also so I guess I need to see which is best to convert. Thanks guys

 

[Boman]

JE Custom,
Thanks for chiming in. I didn't realize the 338 rum was that close lengthwise. Can I pm you to discuss further?

 

[rwk]

WHY!

 

[Cold Trigger Finger]

The 338 RUM is 3.6" oal

 

[J E Custom]

The 338 RUM is 3.6" oal

That is the maximum COAL for any 700 long action. the 338 rum has a minimum COAL of 3.450
and the win has a Max of 3.340 depending on the mag length of the mod 70. (There is a difference
in them)

So you need to measure the mag length to determine which Mod 70 you have to make sure.

On some mod 70's you can build a 375 H&H length cartridge. and some have a spacer in the magazine for the shorter cartridges .

Once you know the mag length that will tell you what cartridge it will take.

And yes you can PM me any time.

J E CUSTOM

 

[Boman]

JE thank you. I'll be pm'ing you.