The operative words being "energy levels" and "loaded", not store bought ammo. Like I said, I'm not arguing how bad the .357 in a rifle is but how good it is with limitations. I just don't want anyone making it out to be something it isn't, because as sure as you do there will that person that thinks it is a 200 yard gun just because someone else said they use their 30-30 out to 200 yards and they read the .357 is as good as the 30-30.
Truth is I've never used the Buffalo Bore ammo so it is wrong of me to say they are not truthful but you have to admit the speeds they give for the 158 and 180 grain bullets sure raises a eye brow. I'm loading 180 grain hard cast lead with gas checks and Hornady 180 grain XTP's and I can't get enough powder of any kind in there to reach the speeds they claim. Sure would like to know what they are using........ a little nitro maybe.
Buffalo Bore ammo is store bought, and it can match the energy levels of all but the hottest .30-30.
The Buffalo Bore 158 grain at 2150fps gives 1622 ft-lbs. That's a chrono'ed value out of a 18.5" Marlin 1894.
Now yeah, that 170-grain bullet at 2200 fps and the 150-grain load at 2390fps you mentioned would put the .30-30 well ahead of the .357, except.....that's not really what they do. Out of a 20" Winny, you're looking at 2012 fps and 2234 fps respectively. That puts the 170-grain energy level below that of the BB 158 .357 and the 150 grain right about equal to it.
There are a couple premium .30-30 loads that it can not match, (Federal Fusion 150 and Hornady Leverevolution 160), but your average or even slightly above-average .30-30 isn't going to do any better in terms of energy.
And Buffalo Bore doesn't have to load them over allowable pressure, they just load them with non-canister grade powders not available to us. Same goes for the Leverevolution and Fusion.
Here's an article that sheds some light on some of these .30-30 loads:
http://www.realguns.com/archives/120.htm
Maybe they do better in some guns, but it's not uncommon for factory ammo to fall well below advertised ballistics. On the other hand, Buffalo Bore is one of the few companies I've heard of that from time to time actually delivers more performance than advertised.