Montana Rifleman, I think you will be able to get to 3050 fps with the 180s on the 7 Dakota
improved. The 300 Dakota improved, necked to 7mm will get you to 3200+ but the case life will be a bit short. The guys that I did that version for, backed their loads of to about 3180 and the primer pockets have held up since then. The 7mm RHB does 3240 with the 180s but shoots best at 3150. Best accuracy is with 86 to 87 grs. H 50 BMG and the 180 Berger jammed .010. The 200 Wildcats ran at 3020 but my gun didn't like them? I have 250 left if anybody wants them?
The 7mmRHB bbl is 28" long and the gun weighs 9lbs total. The base dimensions stay the same with .010 taper removed at the shoulder and tight neck . ( .0025" total clearance.)
Good luck with your projects ---- 7mmRHB