When I was using the 257 STW as my deer rifle I started with the 100 gr BCFBHP and loved it. Hit 3950 fps with 1/4 moa accuracy at 100 yards. My wife popped a record book class pronghorn with this rifle which worked extremely well. IT did show us though that the 100 gr bullet at these velocities(30" barrel) was to light for anything heavier then pronghorn.
Switched up to the 130 gr BCFBHP and velocity dropped to 3450 fps and accuracy at 100 yards was in the 3/8" range. The biggest advantage was the velocity spread, really tamed down with the heavier bullets.
Also, when compared agains the 100 gr FBHP at 500 yards, the 130 was far more accurate producing averge groups in the 1/3 moa range compared to a bit over 1/2 moa for the 100 gr pills.
I used that bullet for several head of game and it worked very well. That bullet was built on the J-4 jacket and at closer range, it was still stressed pretty severely but performed very well on deer size game. Remember though that it is a bonded Core bullet.
At the velocity potential you have with the STW I would highly recommend you use a bonded core if you will be hunting any game that is much over 150 lbs unless it is all past 400 yards in shooting range.
When I developed the 257 AM, Richard designed a beefed up 130 gr BCFBHP specifically for this chambering and its 3650 fps velocity potential. It is a stouter jacket, lead right to the HP tip and with a much tighter Meplat then the J-4 jacketed bullet design. As such, expansion is delayed just enough to perform better on deer size game at the higher end velocity ranges.
I would drop Richard an e-mail and tell him what you have and what you will be doing with the rifle. He can then recommend which bullet he would recommend.
WHile the ULD RBBT will offer higher BC for longer range shooting. If you are hunting deer size game at ranges under 300 yards, I would personally look at a Flat Base Bonded Core bullet from Richard. 130 gr would be my choice.
From bullet drop numbers, the J-4 jacketed bullet produced a BC of .550. The slightly shorter beefed up version for the higher velocity rounds produced a BC in the .500 range. Basically the same as a 180 gr Accubond so that puts it into perspective. Pretty impressive at long range with your velocity potential.
If your just punching paper or game no larger then pronghorns or if all your shooting is at ranges past 300 yards, then the ULD RBBT will work fine for you.
Again, ask Richard, he will tell you what he recommends for your specific needs.
Your 1-10 will handle anything up to the 130 gr with your velocity potential. I even tested some prototype 145 gr FBSPs from Richard in my STW and out to 200 yards then shot pretty well, 3/4 moa anyway!!
Good Shooting!!
Kirby Allen(50)
