I have this rifle SN G 956XXX, currently in .243 Cal. This is the full size receiver and not the short action. IN THEORY, this rifle can be converted to most other calibers by changing the barrel, complete bolt, magazine box, follower& spring and bolt stop when necessary. Of course-it does not make sense due to cost but I got the gun cheap and have a 7mm Mag barrel... my only concern is the receiver rails - did Winchester save money by having the magazine box lips regulate the feeding for each caliber without depending on the receiver rails? What mag box, bolt stop and follower number CODE should I be looking for? Yes, I have too much time on my hands but I am interested. Trading the .243 parts for 7 mm mag parts? Maybe... Mel

Good luck finding the bolt... Find that first - the rest is a piece of cake..

I have converted an 8x57mm 1908 Mauser, a 7x57mm VZ24 Mauser, and a 91/30 7.62x54 Mosin Nagant to 7mmRemMag.

I lengthened the magazine, widened the feed lips, opened the bolt face, and changed the extractor. In the Mosin I designed an ejector over-ride button for removing unfired ammo out the short port.

But so far I have not done any action alterations to M70 Winchesters. It is not the same as sporterizing cheap old military surplus. The M70 actions cost money and are already what they are.

I did just get one of these M70 extractor relief cutters.
http://pacifictoolandgauge.com/slot...el-70-extractor-slot-cutter-carbide.html

The classics are easy to convert.. But not so the PF actions..

Redneck is right. It would be easier to go to a 280. I imagine a M70 with its style of extractor would be easier than a 700, but it's a more difficult than it may seem. You have to open the face of the bolt and modify or replace the extractor. Then you'd need to alter the rails and change the bolt stop and modify the magazine.

Best thing is to sell your rifle and buy a 7mm RM.

I borrowed a magnum bolt and it fits the 243 , I swapped the firing pin assy and it also fits. I don't see markings on the bolt stop, tho...Mel

I'd keep an eye open for a take-off .280 Rem barrel if I were you. Shortest route around the barn!