The 7mm STW is an awesome round.I have a heavy barrel Sendero and it's quite pleasant to shoot without a muzzle brake
.I am using Winchester WXR powder in mine.I use 80.0grs,Win. Large Rifle Primer,150gr bullet=3450fps on the chronograph,no pressure signs and 1/2" groups.This powder is double base and made in Sweden.Reloader 22 is also double based and made in Sweden,may even be by the same company.They seem to be loaded very similar,I have some loaded with Reloader 22 to try out,just haven't made it to the range yet.I also had excellent groups too with 82.0grs. of H-1000 at 3226fps with 150gr bullet and 81.0grs. of IMR-7828@ 3244fps with a 150gr bullet.If you don't have a chronograph,I'd get one,they sure are a good tool when working up your loads.