Here is your evidence...
If you want evidence, go to the Ruger website and download the 2008 DA revolver catalog. You will find this exact information in the catalog.
.327 FEDERAL BALLISTICS (3 1/16’’ REVOLVER)
Caliber Bullet Wgt. Pressure Velocity Energy Free Recoil
[gr] [psi] [fps] [ft/lb] [ft/lb]
.32 85 20,500 990 185 1.46
H&R
Mag.
.327 85 35,000 1330 334 3.08
Federal 100 45,000 1400 435 5.58
Mag. 115 45,000 1300 431 5.62
.38 129 20,000 925 245 3
Spl.+P
.357 125 35,000 1300 470 7.22
Based on the ballistics, .327 magnum is superior to the .38 special +p. With the smaller bullet diameter, these rounds would have a better sectional density than the .38 special round and the .357 magnum round. Given the sectional density and the velocity, I would expect that the .327 magnum would out penetrate both of those rounds. If you look at the Gunblast review on the .327 magnum sp101, you'll see that Jeff Quinn shot completely through a 16" wide pork shoulder with the FMJ version of these Federal rounds.
http://www.gunblast.com/Ruger-SP101-327.htm
The .327 magnum will not be as effective as 125 grain .357 magnum rounds, but what round is? The 125 grain .357 magnum round is the king of hand gun "stopping power". By the numbers, it the .327 magnum is a very formidable round. I want to get this gun for the wife, but if I do, I will shot the darn thing a lot after I get set up for reloading. This is one of the guns that I am really excited about.