Question, right to the point.

I run out of adjustment bottoming the rear sight. So the other option is to speed up fps. Then recoil gets to be an issue. A scope cheats the issue. You will just have to try it yourself. The gun was designed around the 240 gr. bullet. The heavies came later, so did the Redhawk.

In order to get the maximum powder charge in the 44mag case to exploit the 300/305/310 etc, bullet weights I crimp on the bottom groove; as recommended This resulted in the OAL exceeding the length of the SBH cylinder. The Redhawk was designed to handle the longer (heavier) cartridges. Problem solved with the Redhawk (a.k.a. TANK). You may be able to get the OAL down by crimping on the top groove, but that will limit your powder charge, and sort of defeat the intent. I'd also be a bit leery of a six-shot cylinder vs. a 5-shot cylinder in a SBH. I run heavy Garrett's and heavy handloads through my Redhawk and sleep like a baby.

bullets or ammo to use. I have 3 S&W model 29s in 44 Magnum. One will not shoot anything except 180 grain or 200 grain jacketed bullets. The other 2 like the heavier bullets, especially the 265 grain jacketed round nose Hornady bullet. None of the 3 will shoot anything heavier than the 270 grain Speer. So try some of each and see which ones you guns like and shoot best. And let them decide, not someone on here.

calibers made. You are worrying way too much for nothing. I personally would stay away from Buffalo Bore ammo and anything listed as +P. The 357 Magnum and 44 Magnum are already +P rounds so there is no reason to go farther. If you really want to run the 44 to the max you can have a 5 shot cylinder made for it. Nothing is idiot proof so stay away from things marked +P and any handloads that you didn't load and you and the guns will be fine.

ONLY FOR THE REDHAWK AND SUPER REDHAWK AND .357 FOR FA ONLY. IN THE EARLY '60s KEITH REPORTED ON TESTING OF HEAVY LOADS TO SEE WHAT THE SMITH 29 AND SUPER BLACKHAWK WOULD TAKE. THE SMITH STRETCHED AND SUPER BLEW.