Hello General, those are some great looking old S&W's, something about the deep blue on these old guns that makes everybody like them.
Most people, not all start out buying cast slugs that are too hard, the rule of thumb is, don't shoot a soft bullet fast or a hard bullet slow, you will get gas cutting/leading right from the start. Bullet fit is the #1 thing when using cast. Everyone needs to measure their cylinder throats/bore to see what they actually measure, there are many surprises! A easy thing to try is drop a cast slug down each cylinder, it needs to be snug but be able to push it through each one.
I'm sure you've used plated bullets before but one precaution is, don't get carried away with the crimp, you don't want to break the thin plating by over doing it. Also they usually can't be run up too high velocity wise, normally there is a velocity chart available from the dealer.
Running cast bullets fast is easy & you should never get leading if the bullet hardness matches the velocity. I'm running the 250 Keith slug right at 1600 fps in my 10" Ruger 44, its had lots & lots of them down the bore, I haven't cleaned the bore once! I would if it needed it. My slugs are sized .431" & your 44's probaly need to be + or - one thousandths of that to be correct. Most jacketed slugs are .429" or .4295", thats too small for good fit with cast.
Of the 50 or so head of big game I've taken with revolvers in Idaho, Utah, Wyoming, Montana, Alaska & Africa, all were taken with cast. Actually I did take one of my elk & a couple of deer with jacketed but not for a long time, if I thought they were better I'd use them & do think it might be better on deer for close up tree stand type hunting.
Almost forgot & sorry this is a little long. I've made my own cast slugs since 1966, mostly using just wheelweights, the good thing about them is you can make them harder quite easy. You can water quench them, this is the most common way, or you can heat treat them & take the hardness up into the 30+ BHN range. There is nothing out there that will compare to a good cast slug for big game, especially for odd angle shots. Shoot an animal with a cast slug & you can usually eat the bullet hole, that is, it won't be all blood shot normally like a jacketed, expanding slug. That big flat nose just works, always, from any angle.
The cylinder gap at .004" is about normal for S&W guns, we don't change this on my competition guns.
This is a nice cased model 57 in 41 magnum.
Early model 29 S&W 44 magnum nickel, also has the walnut case.
Took this buck last fall at 106 yds, Ruger 357 Maximum & the Keith 173 gr cast.
Freedom Arms 475 using a 370 gr cast.
Lion taken with an 8 3/8ths nickel 357 & the 173 gr Keith cast, shot at 5'
Dick