I'd be absolutely shocked it if gave any more than 1500 fps from a 16" barrel....just not enough powder in the little case to get much of an improvement. My Sierra manual shows a max of 1350-1400 fps with a 16 1/2 " carbine. A +P+ round would likely do a little better, but that would depend on the burn rate of the powder. A .357 Mag filled with H110 on the other hand should do 1900 fps.
Sorry for the not so great news.
