I posted this question on the gunsmithing forum and have received two different answers which both sound plausible. I want to rebarrel/ convert a win mod 70 classic (New Haven) into 300 H&H (I have a supergrade stock ready to go). I was wondering what would be the best donor action to start with in order to minimize the amount of gunsmithing need to make this work. The two response are use a 7mm STW, 300 Weatherby length setup. The other is that the rails on the models 70's are all the same and one only needs the correct feed box to make it work. Can anyone who has done this conversion please chime in since I'd like to solve this mystery so I can start shopping for a doner action.

Thanks Brad

Email Mike Cuypers at Bijou Creek Customs. I believe he's done some...a 404J for JudgeG on a Win 300 RUM action, for one.

I own both a 7mm STW, and a .338 Wim mag in Winchester M70. The actions are identical. I had to mark the bolt to keep from mixing them up. In the .338 you can see where the feed box has been shortened, and how it would be easy to open it up to make it identical to the STW's box. Of course I have no idea why anyone would ever want to rebarrel a 7 STW to something else.

I have several M70 Classic in various caliber. There is a difference between the actions for 338 WIn Mag and the 7mm STW. I have both. The overall length of the actions is the same and the bolts are the same, so yes, a 338 can be converted to a 300 or 375 H&H length cartridge. But the factory original 7mm STWs were built using the Express Action, same one used for the 375 H&H, 416 Rem Mag, etc. Look the the rear bridge. It is shorter on the Express action, requires a different rear scope base (.330 hole spacing on express vs .860 on the long). This opens up the loading/ejction port for the longer cartridge. Also, the magazine does not have the spacer in the rear, and the bolt stop and ejector are moved further to the rear to accommodate the longer cartridges.

I am not sure about the availability of parts from Winchester at this time, but the bolt stop, ejector, and magazine can just be replaced. The ejection port will need some work of you want to open up to make it easier to load and eject loaded rounds.

David:

I think your correct regarding the length. Thanks again for the help.

Brad

My son had Lee Christianson(sp), posts as Redneck on the campfire, build one on a 7mm Rem. Mag. Classic. If I remember correctly, they used a new box, shortened the stop and lengthened the port. Very nice rifle.

should be a very simple procedure to use any magnum action. Plenty of 300 Win and 7mm RM donors out in the wild at good prices if you don't already have the action