Now that RH Outfitter has enlightened me to what will fit my action.........

Which is ballistically superior?? .257 or 6.5 STW?? I'm guessing the 6.5 but don't know.

quote:

Which is ballistically superior?? .257 or 6.5 STW?? I'm guessing the 6.5 but don't know.

Personally I believe the smallest bullet that belongs in the STW case is a 30 caliber.....

Obviously the 6.5 would have a very slight advantage over the .257.....the .264 Win Mag offers very little over the 6.5-06.....using the STW case is more of the same I suspect.

Both would be barrel burners that would not offer much increase in velocity over the 257 Weatherby or the 264 Mag... both of which are already overbore....

6.5/06 or 25/06 are about max for those bore dimensions before you are just burning up powder, and causing faster barrel erosion....

and in my opinion only, both bores are about max efficiency when using the 57 mm case...

6.5 x 57 or 257 Roberts ( the AI adds a little more, but I am not an AI user)...I am a 6.5 x 57 user...

but good luck on your choices...

cheers
seafire

A wider variety of heavier hunting bullets are available in 6.5mm, making it somewhat better suited for medium game at long ranges. Expect a 6.5 STW to give you possibly 50 fps more than a .264 at similar pressures. It will also burn some bit more powder.

As to "barrel burning", it is true that higher pressures and a proportionally larger volume of fuel per bore area both contribute to throat erosion. If you're going to use this as a serious hunting rifle and only shoot it for load development and sight checking rather than using it as a varmint plinker, then your greatgrandchildren will need to worry about replacing the barrel someday.

athe 25 stw is not any harder on a barrel than any othe high velocity round i have put 1500+ rounds through mine and it is still sub moa at a 100 yds

Well just my 2cents. I have a 25-06. Had a 257Wby and 25Gibbs. The last two did not gain much over the 06. I have a 6.5 Gibbs and it will match a 264Wmag. I have a 280, 280Gibbs, 7rem mag and 7STW. Loaded to the same pressure and barrel the STW does not gain you much over the 7mag except the ability to burn more powder.

For my money I would build a 264wmag and set it up for the max OAL for my planned bullet. If I really had to have the STW case then I would not go smaller than .264.