You know Dale, I used to think that was just so much "hooey" that I never really took the time to do it. I would change components at random with no thought about the outcome. Let me state first of all though that 99.999999% of all of my loads are target type in nature. Most of them are smack dab in the middle of the data. Nothing barn burning to be sure. 200gr LSWC in 45ACP doing about 850fps hardly qualifies for "smokin' hot", that's for sure.

Then I loaded some different bullets with the same setup and powder and weight and ..... ended up with a load that was a good 30fps faster from the same gun. These loads were in the same velocity range only in the 40S&W, a cartridge well known for pressure issues.

Take a look at the thread I have about my 40S&W loads using SR4756. Something to consider to be sure!