Last first: Suppressors are basically muzzle brakes that divert and slow the gases, rather than let them exhaust as either a coherent stream straight ahead or in a pattern more or less perpendicular to the bore. That reduces recoil and the extra weight also helps. That said, when I fired Hornady 500 grain loads through the suppressor, it still kicked like a 12 gauge slug. Didn't make a lot of noise besides the sonic crack, but not something I would do all day. That 20-round box may be a lifetime supply of that load for me.
Subsonic loads with heavy bullets, 400 - 600+ grains are a pleasure to shoot. Perhaps you might try that type of reduced recoil load will still a lot of whuump downrange. That leads me to next to last .
I bought 100 rounds of Starfire brass for the 500 for about 60 bucks delivered. Several of those have been reloaded 5 or 6 times. My load is 10 grains of Unique over a Large Rifle Magnum Primer. I have a Lee mould that throws 440+/- grain bullets, and I built the 617 grain mould myself. Primer, powder, bullets and all, these rounds cost somewhere around a dime apiece plus my time. Less than double cheap .22 cartridges. So with these loads, I can literally shoot all day for $10.
Just had a thought. Why couldn't a gun that shot .303 British, 7.62 x 54R, or other large rimmed cartridges be re-barreled and have the magazine, bolt face, and feeding tweaked for the 500 Magnum girth and length? Coments?