I been running heavy hard cast LBT's for a long time here in Alaska out of a bushel basket full of .44 mags. of many different S&W revolvers. I lean towards the 260 to 280 grain LBT's out of my S&W Mountain Gun. I would search the internet for a clean burning powder that tosses the bullet weight you like with good results. Powders have changed since I started with 2400 long ago and then WW 296 ad H110. I quit using Unique as it is a dirty powder for my needs.
I gave up using .44 Special loads long ago, but did use them with 246 grain round nose lead bullets on our snow shoe hairs in the winter. The old rumor is hard cast lead bullets give faster velocities then jacketed bullets with equal powder charges.. I found this true when shooting 300 grain hard casts and 300 grain jacketed bullets years ago.
You could try e-mailing gun writer Brian Pierce, he does lots of .44 mag. shooting.
