Would a 358 Norma clean up an existing chamber in 35 Brown Whelen?

The 358 Norma mag was introduced along with the 308 Norma mag in the late 1950s or early 60s after Winchester introduced the 338 Win Mag. Just a necked up design. That would easily clean up the 30'06 based chamber of the Brown Whelan. You may need to set the barrel back a bit but it should not be an issue IMHO.

The Brown Whelen shoulder neck junction if further forward than the 358N. You would need to set the barrel back.

Naki may be right, but I would check the neck length before I made a decision. The Brown Whelen was a cartridge made by moving the shoulder on a 35 Whelen, and improving it somewhat. It is not strictly speaking a 30-06 based cartridge. Since the 358 Norma and the 35 Whelen are both the same length OAL, the rechambering won't work without a barrel setback, unless the 358 has a short neck to start with. (Don't have my references here to check).

Sorry

Ramrod posted while I was typing. Didn't mean to walk on him.

That's what I remembered too, but I couldn't check to be sure.

. . . . or, you could rechamber to the .35/.300 Winchster, .358 STW, or a .35 on the .338 RUM case. All of these will have a chamber longer than the Brown-Whelen. This assumes your magazine is a full-length of about 3.6".

Found some case drawings, the Norma is actually a longer case over all. Everything looks good until the shoulder/neck junction. Again going by these dimension drawins, .005" longer for the B-W.

It is a 1903, so a longer cartridge won't work. And setting back isn't as easy because of the extractor cut out. Well hell, guess that barrel is pretty much a tomato stake now! I really don't want to go through the BS of reloading the B-W. I see that cases will be available very soon from QualCart, and aren't expensive...but dies are still 200$+ and long wait special orders. Oh well, it was a thought