Ruger Blackhawk revolvers are allowed in Cowboy Action Shooting. They will put you in the SASS category "Modern".
I usually shoot Rugar Vaqueros and my 66 year old eyes do alright. Handgun distance is from 5 yards to a maximum of 25 yards, but usually 10 to 15 yards. Rifle is not suppose to exceed 35 yards, but there are often "Bonus Shots" out to 50.
Targets usually start either all White or All Black, but turn grey as they get shot. To prepare for this; use some 8.5 x 11" grey construction paper at a25 yard range and see what you can see!
Shotgun: Any SxS or model 87 or model 97 20 gauge or larger. Federal made a run of Cowboy shot shells once, They were Paper Hull 12 gauge. 7/8 ounce, 7.5's at 1275fps I fell in love and used that in all my 12 gauge shooting, only I used AA Hulls.
There are 4 guns needed to shoot a SASS shoot. 2 single action revolvers 32 caliber or larger the afore mentioned shotgun and a Lever action or slide action rifle in pistol calibers 25-20 or larger.
I like to take my sons with me so I have 2 sets in 45 Colt/12 gauge, 1 set 357/20 gauge (my wife's and second son's) and a 44 Russian/44 Special 1873/12 gauge set, and can put together another set or two! So I always take two sets of guns so I have back up if there is a breakdown. Fo my club a full season of Cowboy shooting will be 9 one day shoots and 1 three day shoot. A day of shooting will require 6o rounds of pistol, 60 rounds of rifle30 to 40 shotgun shells. plus ammo for reshoots so I take a minimum of 200 45 Colt and 3 boxes of 12 gauge. Times 12 days of shooting is 2000 Metaullic cartridges and 500ish shot shells I shot 3 times that much for weekly practice. I say this because one year of matches equals a normal lifetime of shooting and Colt SAA's & Clones do not hold up as well as Rugers! My first pair of Vaqueros have way over 50,000 rounds without a stoppage! Most SAA's don't make it 20,000! (It doesn't matter who makes them!) Model 92 and 1894 Marlins hold up almost that well. Shot guns need more maintenance!
Ivan