.255 Dean

Found one of my Stevens Tip-ups is chambered in .255 Dean. The .255 Dean was the predecessor of the 256 Winchester Mag and conceived by Harry O. Dean in the early 40's. I've found a bit of information on the cartridge and Harry Dean, but no load data. Anyone have this info?

I will look in my old PO Ackley Books

https://imgur.com/a/TsfKoC0

Hope this helps, so many old cartridges :shock:

Thanks for the reply. I think the loads listed are for 25-20 Winchester. Still looking for info on . 255 Dean

Correct, but reading the text mentioned.255 dean is a short necked sharp shoulder 25-20 offering increased velocity.

I checked v1 and v2 and this was the only mention of it.

http://www.sportingshooter.com.au/as...-is-a-256-dean

I also found another source online that I can't seem to forward.
Essentially it sounds like a 25 WCF AI.


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Thanks for the info. I had not seen that post. I guess I question the writer's evaluation of the .255 Dean as others claim velocity is 2700-2800fps. That's quite an improvement over the 25-20 Winchester. Wish I could find loading data.

I wonder if someone could plug in the case dimensions into quick load or similar and get an estimate for pressure.

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I had an old man as a pal who knew a friend of Harry Dean. Dean was apparently a postman. Seems like Mr. Dean was always the broke sort of gun crank and the word is that he rechambered a .25-20 Savage single shot ( Model 219?) by running a drill bit into the chamber to change the shoulder angle. No one alive anymore can prove or disprove this, but it doesn't sound unreasonable.