As my title suggest; Is the Win. M-70 CRF, 1990's vintage Magnum action (ie. 7mm Mag., 300WM) long enough for a 300 H&H cartridge? And also what about the magazine well? Is it feasable/possible to modify?

Yes - and quite easily as they were chambered in the 375 H&H

I once asked my local gunsmith the same question and he told me this is what he did:

1. Remove the spacer block from the rear of the mag box.
2. Alter the bolt stop
3. Removes a small amount out of the rear of the action so a loaded round can be extracted easily and drills and taps another scope base mounting hole.

Some people claim step 3 is not needed but I am just reporting what my smith would do. Your smith may do it differently.

I've converted several to 7STW. As others have stated I have done it both ways. Using the existing parts and removing the spacer and shortening the bolt stop and ejector. I have also simply bought the proper long action parts from Winchester. If they are available I would go that way. If not it is simple enough to alter the originals.

While the factory H&H has a slightly longer port I din't alter mine and had no issues. They will ejected a loaded round perfectly. Loading seems to work best with a slight forward move then back and down. Sure not an issue to me.

quote:

Originally posted by Snowwolfe:
3. Removes a small amount out of the rear of the action so a loaded round can be extracted easily and drills and taps another scope base mounting hole.

Some people claim step 3 is not needed but I am just reporting what my smith would do. Your smith may do it differently.

Step 3 of course is to change the rear receiver ring to be the same as a 375 M70. It is the CRF actions that will most likely have a problem if not done. The reason being the CRF does not eject until the bolt is fully rearward and that means bolt face/case is well inside the long receiver ring. PF on the other hand is ejecting when the case neck clears the action and that why Rem 700s don't do it.

Thanks for the info gentelmen.