Awesome photos that show exactly why I sold my Ruger .454 Alaskan, and I live in Alaska.
That .454 cartridge was just never meant for a 2.75" barrel. The internal pressures were designed to accelerate slugs out of a 7.5" or longer barrel, in order to generate those high velocities & energies that Dick Casull liked to brag about and advertise.
A couple of things that will help (but not completely eliminate) those therm-o-nuclear muzzle flashes: (1) change to gunpowder with a faster burn rate and flash retardant properties, (2) use heavier 325-360 gr bullets, preferable hard-cast lead & gas-checked. This will contain the combustion relatively longer and burn the powder-charge more completely. Plus, heavier slugs loose proportionately less velocity in shorter barrels, compared to lighter projectiles, so, you will get better energy efficiency. They also tend to produce deeper penetration, which is what that snubbie Ruger Alaskan was designed for; i.e. point-blank protection from very large predators, not long or even medium range hunting of herbivores.
But eventually, I got tired of the excessive blast associated with any .454 load that I tried, and switched to a .480 caliber Alaskan, due to the superior internal dynamics.
To confirm agtman's observation of trends up here, I've also recently acquired a Glock 40 MOS in 10mm and keep it loaded with Underwood 220 hard cast loads. The longer 6" barrel boosts muzzle energy into the mid-700 range. While that's not close to .480 Ruger ballistics, it's not too shabby, and allows for MUCH faster multiple follow-up shots.
But hey, if you enjoy making maximum "shock & awe" on the firing line, don't change anything. Looks like a great crowd pleaser for the range.
Again, awesome photos!