Win Mod 70 Extreme Weather rechamber from 300 Win to 300 Ultra Mag.

[victorc]

I'm interested in constructive thoughts regarding taking a factory Winchester Model 70 Extreme Weather chambered in 300 Win Mag, rechambering the factory barrel to the 300 Remington Ultra Mag, and reinstalling it to the factory action. Wyatt Outdoors has an extended magazine box to accommodate the Ultra Mag cartridge. I'm not interested in weather or not it will shoot super accurate, or why waste time and money at the attempt, just what it will take to make it functional. Thank you in advance.

 

[David Emerson]

Getting the feed rails right will be a bit tricky but you can get plenty of length with the wyatt,s box. And I believe all the extreme weathers have the 1 1/16 by 28 thread so all should be good. Much easier would be to just drill out the spacer in the back of the magazine box and long throat the 300 win.

 

[elkaholic]

I'm interested in constructive thoughts regarding taking a factory Winchester Model 70 Extreme Weather chambered in 300 Win Mag, rechambering the factory barrel to the 300 Remington Ultra Mag, and reinstalling it to the factory action. Wyatt Outdoors has an extended magazine box to accommodate the Ultra Mag cartridge. I'm not interested in weather or not it will shoot super accurate, or why waste time and money at the attempt, just what it will take to make it functional. Thank you in advance.

I would do my 30 SM. A big performance boost and everything would fit. ADG head stamped brass and will shoot 300 PRC ammo very well in a pinch.

 

[MagnumManiac]

Being a standard length action, you will have trouble extracting loaded and fired rounds.
The 375 length Model 70's have the rear bridge milled to accommodate the extra length. The rails, follower and ejector blade will all need to be changed, as well as the mag box.

Cheers.