I recently got this to see how quiet I could get subsonic ammo
It was quieter than offers I've made with 12" barrels but not really quiet enough for one job I need it for so built a 22" Model Seven which is much quieter
I wanted to use it for a muzzle brake test so shot some Hornady 250 FTX ammunition through it to get the velocities, I was very impressed with its accuracy
Here is the video I made, its difficult to reduce the recoil a lot with the 450 & its heavy slow projectile especially with the small amount of powder it uses.
https://www.youtube.com/watch?v=9CXc4Dxok4c&t=2s
I have shot a few animals with it using the Cutting Edge & Lehigh pistol/subsonic projectiles, it works extremely well, a big step up from the 30 cal