This is the .300 WSM case necked down to a .25 while the shoulder blown out to 50 degrees.

He said that he was getting .5" groups with 100 grain bullets @ 4000 FPS!!

Sorry I don't have more details.

This is not the actual case. This is a prototype.

The real case has a little longer neck.

I think that I know what I will build next-

[This message has been edited by Tunacan (edited 05-14-2002).]

Tunucan, who is your gunsmith?

I'd bet Reloader 22, or even R25 would be great in this cartridge with a 100 grain bullet. I've been getting 3,600 fps (24" barrel) out of a 25-06 Imp with 63 grain of R22. And on the Reloading pages of this site, under 25-300 Winchester Magnum, they get 3,813 with 73 grains of R22. So a stiff load of R22 should be able to give you 4000 fps in a 25 WSM "Improved."

To me, this cartridge would be the ideal deer or antelope cartridge. Yah, its' a barrel burner, but are you really going to shoot a deer rifle more than 500 times.

My friend has a 25-06 Improved that I load for him - it produces 3,600 fps with a 100 gain Barnes - X bullet with moderate pressure. And the recoil is much less than my .270. The terminal and trajectory results are incredible. Sighted in 1.5" high and assuming the scope height is 1.5" above the bore, this bullet is only 2.53" low at 300 yards and is still going 2,850 fps! Speed kills.

A .25 WSM, with a case somewhat larger than the '06 improved, MIGHT reach 3600 in a 26" barrel, with luck, but you'll be pushing the pressure envelope.

By the way, nothing you can do the the WSM case will allow it to equal the case capacity of the .300 Winchester, and despite all the new-gun-speak and unadulterated advertising hype, a smaller case cannot generate higher velocities than a larger case in the same bore without higher pressures, period.

BE SAFE!!!

Somebody's always wanting to rewrite the laws of physics with a new shoulder angle, or a less tapered case, or a more tapered case, or by turning off the belt or some such other world-shaking modification to a cartridge case.

Larger capacity cases with larger bores will ALWAYS produce higher velocities and/or lower pressures with a given bullet weight than the smaller of each, assuming the barrels they use are substantially similar.

I don't doubt that someone shoved a bullet of some weight out the end of a barrel at some particular velocity. It could have even been done within acceptable pressure limits, since some individual barrels are "fast" and give much higher velocities than seemingly similar barrels.

But to claim that one can reasonbly expect to achieve higher velocities with a smaller case and smaller bore without higher pressures is nonsensical, and should it happen by chance on occasion, not recreatable in another gun.

quote:

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Originally posted by DB Bill:
Those must be Canadian feet per second!

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That one tickled me