When I was developing my own 10mm loads, which included a weaker 180gr hard cast at 1300 fps for plinking, and a 1250 fps 200gr jhp, I fired several factory loads over the chronograph to see what factory full power loads did.
I also shot some target loads over the chronograph.
Here's what I found:
(5.3" barrel so 0.7" longer than factory glock barrel and tighter...and a 22# recoil spring)
Buffalo Bore does what it says it will do. I tried the low recoil stuff and the high power hard cast and their velocities were spot on.
Underwood was 50 fps below the 1250 they claimed in with a 200 gr jhp. I tried two different boxes/lots and they were 1200 fps in a 5.3" Alpha Wolf barrel and 1160ish in the factory glock barrel.
Double tap was slower also. In the 200 gr hard cast.
I fired some federal hydrashock and target ammo over the chroney and they hit the box flap velocity too, but they do not claim to be high velocity.
It was a small sample, but if I was buying factory 10mm for hunting or carry, I would buy buffalo bore. I will say Underwood was very accurate though and not "weak", just not as stout as buffalo bore.
However, my own load does fully utilize the 10mm's potential and I would bet my life on it.