The 760 mags are all the same box. The difference is the followers and the spacer blocks used in short action calibers. If you look at the photos above you can see the spacer blocks. If you can find followers for te 35 Rem you can use any of the short action cartridge mags.
And I recall that the magazines for the 742 will work as well but I don't think they made those in 35 Rem.
Short or long doesn't make much of a difference. The 760/7600 mags suck. I had a .35 Rem that wouldn't feed for squat with the .35 Rem marked mag. I put in a 30-06 and tried it...fed flawlessly. Tried a .270, flawless, tried a .308/243/7-08....yep, flawless. Not one of them looked the same. If you have trouble with your gun feeding, bet your wife's paycheck it's the mag.
