Am getting a supresesed ruger 77/44 wanting to find a load for the 240-300 gr bullets in the 1000fps range for maximum quietness. Any help appreciated.

Not sure of the barrel length on the 77/44
I would think that you would want a light charge of a fast burning powder to produce the least amount of gas and the lowest pressure at the muzzle.
I put some numbers into quickload
44mag 18" bbl
240 JHP 6 gns Unique 1001fps 798psi muzzle pressure
5.4gns Red Dot 1013fps 637psi muzzle pressure.

300 JFP 6.5gns Unique 1005fps 767psi muzzle pressure.
This is where I would start.

I use 8 gr of N310 with 240 gr XTP. Av velocity is 1034fps. 7 grs of Clays also works well at 1000fps. With 300 gr bullets 10 gr of N340 works very well at 1020 fps. I have found that the Vitivori powders produce the quitest loads with the suppressor. Here is a picture of my suppressed 77/44. If you want loads useing other powders let me know.