255gr SWC in 45 acp and 45 Auto Rim

[BKSSNIPER]

I bought some 255gr SWC to use in my 45acp and 45auto rim.
I loaded the first rounds last night and shot them today. I loaded the acp with 3.5grs of Bullseye and the AR with 4.0grs.
Both bullets loaded to the crimp groove.
Shooting them thru the chronograph today they both averaged 680 +/- fps. But there were huge velocity variations on both loads. They both shot well. The revolver AR rounds had several cylinder fulls where there were 3-4 rounds cutting one hole at 15yards off hand.
I’m looking for any suggestions on lower the extreme spread.

I’m weighing each charge and using a Redding profile crimp die.

I know there is some room to increase the powder charge or change powders.

Does anyone have any experience with this combination that can offer some advice?

 

[Lightning8]

You may have to search some very old pistol competition sources for 255 load data. Back before the wondernines, etc. took over, there was interest in 1911s shooting 255s (slow) for perceived reduced recoil but you could basically watch those rounds fly down range. Measuring SD/ES was not a thing back then. Some loaded the 255s as hot as possible for bowling pin matches too. Most competitors quickly moved back to 185/200 SWCs for competition. Clays (just plain Clays not the other versions) was the powder for the slow 255 loads.

 

[Aftermath]

Fillers for Reduced Rifle Loads - Shooting Times

Two classes of fillers for reduced rifle reloads are 'puffballs' and granular. Puffballs are the most troublesome, but granular is no cure-all.

www.shootingtimes.com

You are going to want to find a powder that fills the case better.