Given that I am a lefty, I know of no recent manufacture bolt guns that are factory std in either caliber. It will be a semi-custom proposition.
Zastava's 20" FS and standard 22" both are available in LH, and at very decent prices. In Canada, that is. I don't know about the States.
After having owned a M7400 Remington in .35 Whelen (and a single-shot NEF in .35 Whelen), I'm very impressed with that cartridge when the chamber/action allows long-seating of bullets. I'm talking 2550 fps to 2635 fps from the 250 Speers and Hornadys. Shot a good bear with the 7400 using a 200-X at 2835 fps.
I went looking for another .35 Whelen and came home with a 9.3 x 62 Tikka T3 Lite. It will fire the 286 Nos Partition at the same max speed as the 250 in the Whelen. Easily over 2700 fps from the 250 AB and over 2400 from the 320 Woodleigh PP. There is really not a lot of comparison between 3750 ft-lbs from the Whelen and 4365 ft-lbs from my 9.3 x 62. The 9.3 x 62 is readily available in Canada, as well as components for handloading. You would be hard pressed to find new .35 Whelens and ammo. Remington is the only source when available. It isn't all that popular on this side of the border. The 9.3 x 62 has become a hot number.
In my considerable experience with a number of mediums, including .338 Win Mags, a .340 WBY, .35 Whelens and a couple of .375 H&Hs, the 9.3 is the overall best in my view when ballistics, weight, handiness and recoil are all taken into account. And at over 2000 ft-lbs at 500 yards from the 286 Nos Part, it isn't just a medium-range rifle. Think of it as a .30-06 on steroids.
Bob
www.bigbores.ca
