im just built an 7mmstw on rem action vith lothar walther ss match barrel 28".vhat velocity can i expect from that barrel im going tho juice 160gr accubond vitsh powder is best i have mrp and mrp2
linkan

you should expect about 1,160 M/sec

You should be able to get velocities in the range of 3450-3600FPS. With the heavier bullet and the large overbore of the 7STW I would look to the slower powder of the two.

My experience with the STW and both a 28" PacNor and a 28" Krieger with 168gr MK in a 1K benchrest rifle is about 3200 to 3300 fps. If you try to push it past that, the life of your brass will be considerably shortened. I was able to get 3400 with 168gr bullets, but the brass only lasted for about 3 shots before the primer pockets had enlarged so much, the new primers would just fall out.

Winchester brass seemed to be a bit harder than Remington brass and would last a bit longer.

BTW, the reamer used for both of these barrels is a custom BR reamer with and a tight neck and chamber dimensions such that there was very little room for the case to expand. The main reason I was so concerned with the life of the case is that I have turn the necks on all my cases and initial case prep is very time consuming for BR type shooting.

My two 7mmstw's with 26" barrels produce just under 3300fps with 160gr bullets.