If I recall the history correctly, the 25, 30 and 32 Remington were rimless versions of the 25-35, 30-30 and 32 Special Winchester cartridges. So those three should have the same rim diameter. The 35 Remington may have been based on the 30-40 Krag, but without a rim plus other dimensional changes. In a way I'm amazed that the 35 Remington is still produced today, there must be a lot of Marlin 336 rifles in 35 Remington out there!
The Remington family of 25, 30, 32, and 35 were direct competition to the Winchester .25-35, .30-30, and .32 Special. Winchester had no round to directly compete with the .35 Rem until the 50s.
While they were a "family" of rounds, and were all in the same rifles (models 8. 81, auto and 14, 141 pump and the rem bolt gun of the era (model 30??) they weren't all the same case. The .30 and .32 are, but the .25 is a bit smaller and the .35 is bigger (head size), so there's no making .35s from the smaller head size brass.
Remington dropped those rifles with WWII and by the 50s stopped making ammo as regulr production. The .25,30 & .32 faded away. What kept the .35 Rem alive (barely) was Marlin and their 336 lever gun in .35 Rem.
What kept the .35 going was despite the unimpressive numbers on paper, in the deer woods, it hits like the hammer of Thor. Observed results, not paper ballistics kept a loyal though small following. The .35 knocks em down, hard!
For nearly 3 decades if you wanted a .35 Rem, the only choice was a Marlin 336, and that suited a fair number of deer hunters just fine.
The .35 Rem got a boost in popularity and interest when Contender shooters discovered it could be used in their single shots, where, again, it still hits like the hammer of Thor.
when you can find it, ammo or brass buy it, and buy more than you need if you can. Its a good round, does its job better than the paper ballistics imply, but its not popular enough to be a regularly produced thing, and in today's situation none of the "niche" rounds are getting the production they had even a few years ago.
I hope you can find enough for deer season this year, good luck! When you do find some get enough for a few seasons (at least) IF you can.
(and if you think finding ammo for a .35 Rem is bad, try finding some for a .350 Rem Mag!
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