They'll be stronger I'm sure, Sarg, but have slightly less capacity. The added strength should outweigh the loss in capacity for sure. That's what I'd do. The Casull SAAMI data far exceeds lever gun pressures at 57,000PSI.

The Casull data in Barnes book has a 2 1/2 thousandth's smaller diameter at the head, with the .460 being 2 thou. smaller - both than the standard for .45 Colt. The .460 has a .002" larger rim - probably not a problem at all.

I don't have any .45 Colt brass that isn't loaded in my 'ctg. sample's' bin, Homer. Actually I only have WW solid head, like yours and Dominion balloon head brass there.

I'll check with my Bro - he might have some RP brass and/or Fed. I or he can weigh.

With the Starline brass being lighter, I'm prety sure they do not have the strength of WW cases - but it depends on the brass thickness, composition & temper at the web & head.

I found the easiest load to check first, was Ross Seyfried's .44 mag pressure duplication loads for the .45 Colt.

I used Hornady bullets. Ross noted that Fed brass were the strongest, but I've a feeling he checked only WW and maybe Starline brass too. Yes - Federal was stronger than those in my testing as well.
I was using Fed brass to get a ground floor base expansion on the back-end-scooped chamber of my M94, it's weakest spot. Too bad they felt they had to build the loading ramp at the rear bottom of the chamber, weakening the chambering at that point. Having a .44 mag pressure line to load to, helped a lot.

After finding that RP brass was stronger yet, I was able to load to it's strength and when switching to W680 powder actually bypassed 1,700fps with both 300 and 340gr. cast bullets.

Recently, while looking for an article for another forum meember, I found someone elses loads for a .45 Colt Winchester that looked very good.

44 mag pressure loads gave 1,584fps with a 300gr. duplicates using W296 powder and is the black powder .45/90 Winchester load. To do that in a .45 Colt case is a wonder in itself, and with safe pressures. Fun gun to plink with, or shoot pigs or camels even, I'll bet. They sure worked well on our Rocky Mountain Elk.

Right this moment, I cannot put my hands on my .45 Colt manual - it's there somewhere in the great mess down below & when I find it, I'll scan it for you, Homer.

Edited:: I can not find my old data - so I removed what I thought were the loads that Ross provided in W296, as they were from memory & might have been in error- and that can be a fleeting thing, sometimes and errors are made. I suggest to use only published data, or that which is carefully worked up by yourself.

NEVER use someone else's maximum loads - NEVER!