Re: Subsonic .44 magnum loads?
What kind of bullets do you want to shoot?
My suggestion would be to get the heaviest 44 bullets you can find. I know 300 XTP's exist, I've made 460gr lead ones from a 500gr mould designed for 45 cal and then individually turned 20 thou off each bullet, sized and seated a gas check.
Look at Red Dot for a powder to use. It's very fast, and some people find it to be very dirty. In a suppressed, slow application like this it is surprisingly clean burning.
Start with them being supersonic and work backwards.
In my revolver I can shoot 240 LRN @ 1000fps with about 11gr of Unique. It goes supersonic from my dad's 20" barreled handi-rifle combo gun.