Re: JDJones75, 257 STW information...
Donham, I agree that the number of revolutions per minute achieved by a bullet is the key to it being stabilised and also being accurate.
Unfortunately the Bullet manufacturers don't publish the number of revolutions on the side of the box, only sometimes they publish that it needs a 1 in 7 to 1 in 9 twist, etc.
I agree that increasing the velocity sufficiently can stabilise the bullet, but often the velocity increase needed is beyond the capacity of the case being used.
I have found out that in many cases you have to shoot to find out, and will use several personal experiences.
About 5 years ago, I decided to try the Hornady 75 grain Amax in my .224 Clark, and thought that the extra velocity I would be achieving should stabilise it in my 1 in 10 twist barrel. However, despite recording 3,830 fps and 275,760 revolutions per minute the bullet keyholed into the target. I subsequently found out that some benchresters had done extensive research into the 75 grain Amax and they found that you needed 280,000 rpm to stabilise it, best accuracy was around 290,000, and that the bullet started to come apart when 320,000 rpm was reached.
In 1986, I had a 220 Swift AI built up and used a 1 in 12 twist which my gunsmith thought would stabilise the newly released 69 grain Sierra HPBT. Despite achieving 3680 fps and 220,800 rpm, the bullet keyholed into the target.
Yet my 1 in 10 twist barrel (that was formerly used for a .224 Clark, and currently is a 22/250AI), will stabilise the 69 grain Sierra HPBT at velocities ranging from 3100 fps (223,200 rpm)to 3400 (244,800)
My 25/06 AI with 1 in 10 twist barrel is achieving sub 0.5 moa from the Nosler 115 grain BT at 3250 fps (234,000 rpm), and I estimate would push a 130 grain bullet to about 3150 fps and 189,000 rpm, which seems a low number for what is probably a long bullet.
The 257STW should achieve 3400 fps with the 130 grain bullet and with 244,800 rpm, may stabilise it. However, long bullets require high rpm to stabilise, as in the case of the 75 grain Amax.
However, I agree with you suggestion that twist rates used for 140 - 150 grain bullets in the .264 calibre should work for the 130 -140 grain bullets in the 257.It will be interesting to see if this eventuates.