RE: WSM
 

Bearhuntr-The original poster was asking about the 7mmwsm so I never bothered with the 270wsm.Yes it will produce more velocity than the 270win but not more than the 270wby as browning and winchester would have you believe.

No mercy-You compared one factory load in two rifles.We chronographed several loads in a few rifles and the larger 7mmremmag and 300win mag did produce more velocity with all loads tested.
You say that the rifles that you tested had equal length barrels.
Winchester does use the same 24" length barrels for both the regular magnum and wsm's in the model 70 featherweight model but they use barrels 26" long for the regular magnums in their other models.In most browning rifles the wsm's use 23" barrels while the regular magnums use 26" barrels.The bars use 24" barrels for the regular magnums while the wsm's have 23" barrels.Therefore in that one specific model you might possibly find a specific wsm rifle that makes the same velocity or possibly slightly more velocity than a specific rifle chambered the regular magnums(due to tolerances in rifles) but in all other models the regular magnums have a definite velocity advantage due both to their larger case capacity and their longer barrel lengths.

The big selling point for the wsm's is that they produce nearly the velocity of the regular magnums in slightly shorter and ligher rifles.That they do.But if the wsm rifles are slightly lighter than the magnum rifles the recoil will be very similar as well .

The bottom line is that with the possible exception of one specific winchester model where the gap is so small that it could go either way,the regular magnums do produce more velocity than the wsm's.