Over the years I have tested many loads in a consistent manner: a round fired through a bath towel folded so there are 4 layers to penetrate (simulating moderate to heavy clothing) into my swimming pool---straight down of course! The towel is laid on the water and the round fired before the towel soaks up very much water, like within a second. I have tested many different calibers and loads this way, all for consistency's sake. I have also chronographed many different rounds out of different barrel lengths. Obviously this used to be quite an interest of mine!
Some observations:
***Gold Dots, regardless of caliber or velocity, seem to do quite well until you fire them through the simulated clothing. Then they don't open up very well. I won't carry them for that reason. CAVEAT--> I haven't tried the newer "short barreled" rounds.
***Ditto with HydraShoks.
***CorBon's Sierra JHP's work well even after clothing, regardless of caliber or velocity.
***CorBon's DPX loads work well also, even after clothing (tried .40 and .45).
***Remington Golden Sabers are "okay", but the clothing retards expansion to a degree (but you still get SOME).
***Factory published velocities are utter BS. They are almost always a good deal less than advertised. CorBon, however, seems to be pretty close to advertised velocities.
***Don't believe the "50 fps loss of velocity per inch of barrel" rule. It's more like 50-100 fps per HALF INCH. This is regardless of manufacturer. Example: a CorBon 135gr .40 load does about 1300 fps out of a Glock 23 (4" barrel). However, it drops to a little over 1200 fps out of a Glock 27 (3.5" barrel). So that's what, maybe an 80-90 fps loss? This DOES affect bullet performance, trust me.
Oh, BTW. The Winchester 155gr .40 Ranger load penetrated the towel and about 48" of water to punch a hole through the bottom of my pool! A little too much penetration. I stopped carrying them and my wife stopped my testing!
Thank God for underwater patching kits!