I have had several people call me asking about 257 WSM Ammo. I have heard that the 300 WSM can be sized down. Have any of you folk had any dealings with this. I know a little about case forming but have always ben able to purchase the dies to do it with. Help me out with this with the procudure if there is one.

I ran it through the computer-modeling program with a number of powders, shoulder angles, and shoulder diameters. It looks cool, but it’s just a 25-06 class round. Go for it if you feel the need to be different. It’s not close to a 257 Weatherby though.

I will advise, thanks!

actually, i did this this round 12 years ago this month .. as soon as the offical 300 wsm drawing was released, kiff made my reamer, straight necked to 257 .. when the 270 WSM case came out, i immediately swapped to that case, as the necking was easier.

as for dies, just a 300 wsm REDDING with the bushing sizer

Mick, you need new software! the 257 wssm is a direct pairing for 25-06

ammoguide lists the following in terms of capacity
78.5gr 270 wsm, 270 weathrby 80.9gr
803gr in the 257 weatherby ... so the wsm would be within 1.75gr of the 257weatherby

i was within 100fps of advertised 257 weatherby, with a 24" barrel, and wasn't showing supr high pressure...

the round is BORING as white toast and plain scrambled eggs ... worst groups were under 3/4 of an inch, far less whooha than a 257 weatherby, and just, flat out, boring....

this is also, of course, when i was bitten by the bigbore bug badly, and was spending most of my range time with 577ne, 470 mbogo, 458 ackley/lott and winmag ....

it loads to faster than 270 wsm, btw...

but, unless your heart is tied to the quarterbore, it does nothing of merit better than the 270 wsm ..

i tore mine down and rebarreled that rifle to 416 AccRel

I'm down whith that. I have an excited customer that has caught the custom wildcat fever. I think he has already bought the rifle and if he just has to have it, I will get the bushing and make the ammo for hin. I think its a waste of time but its his pockets. I had a friend tell me that he was reading one of the gun publications and that Winchester was comming out with the .257 WSM in 2012. I called the folks @ Winchester and they said that it was not so. The pockets will decide on this one I guess. Thanks a heap!

get the 300 or 270 wsm bushing dies, and a 25cal neck sizer and crimper... and then get bushings rounds what, .257+.03 or so? i've get a measurement off the neck of a fired case and a loaded case..

quote:

Mick, you need new software!

OOPS, Sorry guys, it’s not the program, it’s the operator. When I import cartridge data into QL there are a number of data fields I have to manually enter a value. I didn’t get that done properly (entering 16 instead of 26 in the barrel length field) so the 257 ended up handicapped in the comparison between the other two.

I didn’t save the work so I would have to start over but I think Jeffeosso cleared the waters that I muddied.

I have a 25/300 wsm.
No regrets what so ever. I have a chronographed hunting load of a 75gr. vmax traveling at 4278-4285 fps.

it has killed many whitetails, in fact my 12 year old killed one at 330 yards this fall with it.

this load gives me 1/2" moa after third shot, barrel is warm, it opens to 1 1/2" But while hunting never shot more than once.

Bad ass, now I want one.

I built and own a 6mm WSM. I've used a 6.5 WSM on elk but I don't own that one.

The 25 would hit somewhere in the middle... of course.

With the 6mm WSM I'm not trying for raw speed, I want high BC, long range type stuff. I use the 115 gr DTAC bullets at 3310+/- FPS. It's shooting between .24 and .53. That's about what I would expect.. It's fun fun fun!

Zeke