Well, learning has occurred. I had read that large rifle primers were too tall for pistol brass but never tried them. After reading this I primed six new Starline .44 Magnum brass with six Winchester large rifle primers. Lo and behold! They fit just flush with the base of the cartridge and I test fired one each in my .44 Ruger #1 and my Ruger Super Blackhawk without issue. Since a lot of my .44 ammo will be shot thru the #1 and my 1894 Marlin this will work nicely even if the revolvers would balk at ignition.
When the component drought got real I discovered that the only thing I was low on was LPP and you sir have just relieved my tension. Thank you.
Alliant Unique used to have a warning against using magnum primers due to pressure excursions. Have you seen any issues with that powder and rifle primers in pistols? FWIW I’ve shot a lot of Unique fueled .45/70 ammo in rifles without any problems.