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WW-296 and Lil Gun are NOT the same powder. I think you might be confusing Lil Gun and H-110. Pressures are much lower (generally speaking) with Lil Gun than with H-110, but in some instances it lacks the accuracy of H-110.
Some (if not all) of the lots of H-110 are surplus WW-296. There is also WC-820 which is a surplus powder that loads and shoots just like 296/110. Not trying to be a smart A--. Just did not want someone to get hurt, or disable their gun.
At one time Midway carried two different R-P 158 gr. HP bullets in .38/357 caliber. One was made specifically for the Max and had a slightly different profile and a smaller HP cavity. They are considerably tougher than the standard 158 JHP 38/357 bullet. It has been some years since I ordered some, and I am not sure if there are any left.
I have tried a number of different bullets in my .357 Maximums, but seem to have better luck with the CPBC 180 and 200 gr bullets. I tried the Nosler 180 Partitions, but for some reason pressures were unusually high. Just be sure you are using the correct primer. As previously mentioned the R-P 7 1/2 is pretty much the gold (no pun intended) standard for this cartridge.
The Maximum will pretty much do most everything the .35 Remington and the .357 Herrett will do in a Contender, but without the aggravations of poor extraction and extensive case forming. Good luck.