The 300 win mag was not yet born. It should be a 300 H&H.

I had an early 50's in 300 H&H and it too was marked 300 Magnum.

Note, some were rechambered for 300 Weatherby, if a 300 old Magnum is fired in the rechamber it will fire form to the Weatherby case size.

I did not realize this post predated me here until I happened to notice the date part way down page 1.

rough count, I've owned 3
SG's in 300 Mag, 375 H&H Mag and a low digit pre war 30-06.

I've owned 6 or so pre war models, 10 or so transitional models in 20, 30-06, 257 Roberts. I've owned 4 or 5 264 magnums in the standard, 1 featherweight 264, 1 featherweight in 243 and one in 270 Win. I've owned probably 15 early 50's to 63 ones, most were in 270 and 30-06 and a standard 375 H&H. I've had 2 custom ones and still have one of them.

I do have Rules book, Mrs Model 70 bought it for me one Christmas.

Speaking of Mrs Model 70, her first deer rifle was a custom pre 64 model 70 she flat stole from me. I had a custom 6.5 Swede on a new commercial mauser action, perfect for her, nope she looked at the guns in the safe and pulled out my favorite one, the one I used. This was almost a disaster. Luckily I had 10 or so scoped pre 64's sighted in and 6 or so off brands, like Weatherby, ready to go.

The gun has worked well for her, she has shot many deer with it.