I am considering having my Model 70 (Classic Sporter, with CRF), which is currently chambered in .300 Win Mag, rebarreled in .338 Magnum. I am trying to figure out whether I would need any work done to the magazine, feed rails, follower, etc. for this conversion. It appears from the cartridge diagrams that the brass is identically dimensioned, except that the .338 is .002" wider at the shoulder than the .300. The two cartridges seem to have the same OAL.

Will this conversion require any work other than screwing on a new barrel and headspacing it (aside from possibly enlarging the barrel channel for the new barrel, of course) ?

Have you run the numbers on selling the perfectly good .300 WM and buying a .338?

If you take off the .300 WM barrel you have destroyed it's value and it's installation value. Unless you really know you want a special barrel in .338 WM another rifle is out there right now for you.

Here is an even easier idea! Load up your .300 WM with 200 gr Partitions to 2972 fps with some IMR 4831 and at 450 yards it will have more energy by 120 foot pounds than a .338 WM with a 210 Partition!! Not only that but it will drop less and drift a lot less in wind.

There, I saved you $400. Send a check in my name to the NRA ILA.

[ 03-04-2003, 07:34: Message edited by: Savage99 ]

If you look a bit closer you'll find the 300 Win Mag with a 200g bullet, will have superior energy way out beyond 400 yards, and better ballistics, than a 338 Win Mag with a 225 bullet. The biggest difference will be the sectional density of the two slugs.

But, for years I hunted with a 300 Win Mag. Had a couple of unusual experiences with the 300 and opted to go to the higher sectional density of the 338, and I've never looked back.

It's the ballistic coefficient that determins how a bullet will carry and not the sectional density.

I am not big on sectional density as bullet construction matters more but for the record the SD of a 200 gr .308 bullet is .301 and that of a 225 gr .338 bullet is .281.

In any case these are both powerful cartridges and are good for all around use.

I have exactly one 300 Winnie load - the 200 Partition at 2940 or so. Shoots flat, hits hard. I doubt you could tell any difference between that and 'most any .338 load under ordinary conditions. Keep the 300 or better yet, buy a matching .338! Woo-hoo!

Redial

Like redial, the only load I use in my .300 Winnie is a 200 grain Partition, at about 2950 fps.

About the only thing I would think you might be better off with a .338 Win Mag for is using 250 grain bullets on Brown or Polar bears.

Of course, you never know when you might need that extra oomph, so I also vote for getting a .338 WM in addition to the .300 Winnie.

BigBrass, back to your question, which everyone seems to have ignored: There should be no work required on any part of the action or magazine to rebarrel a .300 Model 70 to a .338.

Now, despite the similarity in power of the two cartridges and general suitabliliy of both for the same types of game, you would gain the advantage (likely) of a much better fitted chamber and more precisely headspaced barrel with a new custom barrel. This offers potential advantages in both accuracy and reloading.

Whatever your reasons for desiring this conversion, it's your gun and your choice, and it is as simple as any rebarreling project gets.

Thanks, Stonecreek.

And thanks to the rest of you for your comments. As to my reasons for converting my .300 Win Mag. Model 70: I am having a good new .300 Win. Mag. built on a Mauser action; and so I thought that rather than just rebarrel my Model 70 in .300 Win Mag. again, and end up with two of them, I might like a .338.