Originally posted by Hal
I fail to see any significant difference between a 124 gr 9mm out of a Browning Hi Power or any 125 gr . 357 out of a 3" or less snub.
The difference is that you're comparing a full-sized service gun to a compact CCW gun. If you want to compare a 9mm to a .357 Magnum snub, do so in comparable guns. For example, a S&W M60 with a 2 1/8" barrel is 6.56" long while a Glock 26 with a 3.43" barrel is 6.54" long. If you start shortening the barrel of the 9mm to 3" or 3 1/2" (common lengths for compact or subcompact 9mm's) then the .357 Magnum is going to be going substantially faster. Also, I think there's a pretty substantial difference between a 147gr bullet from a Browning Hi Power and a 158gr bullet going 100-150fps faster
from a .357 snub, much less if you chronograph the 147gr 9mm from a small gun.
I've said this numerous times in the past. I don't get all excited about a couple/three hundered fps for one load or caliber vs another.
Simple, there's a significant chance that two round, fired back to back from the same revolver, can vary by a couple hundred fps.
That's pretty bad news because a couple hundred fps is more than enough difference to be inside or outside a particular bullet's designed velocity window. In nearly every chronograph test I've ever seen or read, an extreme spread of 100fps or more is highly unusual and may indicate a problem with either the gun or ammunition such as a weak recoil spring or inconsistent powder charges.