Great cartridge with a lot of history behind it. Reading Whelen's pre-war writing as a kid back in the early 60's, it sounded like just the ticket to me if I ever got out to Colorado. At the time, with only a .22 Winchester single shot and a Remington 722 .243 for woodchucks, I knew I was under-gunned.
Then later when Remington came out with their model 700 in .35 Whelen, I had the bucks and immediately indulged in one of my boyhood fantasies. I had the gun glass bedded by Gary Roman, here in Louisville, & began load work ups. Sierra 225's were flat shooting out to ~250 for me, and I found I could easily boost them to over 2550 fps with the then available IMR 4320. With that bullet I've killed three elk, one at a paced off 250 yds; the others much closer in, as well as several deer. The gun truly loved them, and if I didn't shy away too much, they'd go into inch and a quarter for the first three.
But the gun, while a bit heavy for deer in the timber, is quite as good with 200 gr Remington RN Core Lokts, Sierra 200 gr RN's, and Hodgen's equivalent. Loaded to ~2500 fps, these are comfortable to shoot and practice with and will flat out hammer whitetails. While I'm a long time fan of Marlin's in .35 Rem with these same bullets the Whelen will push the easily 200+ fps faster giving some spectacular expansion. As a result, that old 700 still gets some local use. It's been my one and only elk rifle since '88, but now at 77 yo, those days are behind me. Son #1 will probably get it one of these days.
The .35 W is a reloading round, always has been & yeah, you've got to pay attention to die adjustment with regards to head space. For the most part, I make my own cases from LC match brass, fire forming them with Unique and RCBS's 35-200 gr FN. That bullet, BTW, pushed over 2000 fps is a heck of a deer killer. Gas Checked, and cast from 50/50 wheel weights & pure lead, it'll mushroom nicely on ~130 lb. (dressed) KY whitetails and give through and through penetration no matter where you hit them. I load mine to ~2300 fps and get no leading either. SR4759 is my powder of choice with any low velocity cast bullet in the .35 Whelen and 4895 or 3031 will do for faster velocities.
Lastly, if you've got a supply of .357 bullets revolver bullets, any of the 158 gr SP or JHP's make up into great practice rounds, and are also great woodchuck killers. I've not tried any that are lighter, but suspect they'd do OK too. For my .38's and .357's, I cast up a lot of Lyman's famous 358156GC, and have found that it's a suitable, light recoiling practice round. Unique is good for this as are Herco, and 2400. I size them to 0.359" and cast with a straight wheel weight alloy sweetened with a bit of tin for good mold fill out.
Overall, IMHO, the .35 Whelen is a good choice for the guy looking for one rifle from the big bears down to whitetails...IF: he's a reloader and accepts that this cartridge is not for cross the canyon shots. Shots to 300 yds are the limit IMHO, and only then if the shooter's done quite a bit of range and wind estimation to place his shots well. A bit heavy for deer when scoped properly, that same weight is a plus with heavy recoiling 250 gr spitzers. And with 200 grainers, it's down right pleasant...about the same as an '06 with standard 180's.
Just a last thought: For a one bullet for all uses, Hornady's 220 gr FN, pushed a bit will do well on both elk and deer inside 250 yds. I've had good/great accuracy with it, and killed several deer, tho no elk.
Best Regards, Rod