I believe you are getting two different revolvers mixed up. The Single-Six is normally a .22 rimfire. The .357 is the Blackhawk. Both are very fine firearms.
What length barrel does it have? $600.00 is a good price for what you describe.
Came real close to buying a Mossberg 990 aftershock. After doing some research before buying , I found several people stating it was very picky on ammo and had lots of failure to extract fired shells.
Anyone have any first hand info?
Many tests have been done concerning the .380. The best round out of all the testing was the Hornady XTP 90 GR. .380. Any of the .380 rounds that expand don't penetrate.
I will continue to carry my LCP II with the XTP ammo in it.