You might check with Berger et.al. and see what they recommend for twist rates on their bullets. They might be too long to stabilize.
3100 +/- fps. in your Rem is just about the limit even loaded long. The old Rem factory data showed 3050 in a 26 in. barrel. The 3-4 grains difference in the Mashburn is probably worth 50-75 fps. max. not including individual variation. All 3 cart. are 3050 +/- fps. guns with 175's.
Warren Page did it all with one of these using a 22 " barrel and 3050 fps. from that barrel (Rem factory chroned)! That's why I think with modern powders and a 26" barrel 3100 is doable.
