As built, this was intended for black powder ammunition. Smokeless didn't become approved by S&W until some years later. US factory ammo in these older calibers has been loaded to very mild specs for years, largely due to the existence of so many older BP era guns and the fact that many people simply used whatever ammunition was available to them.
There have been endless discussions on the use of smokeless in BP era guns on this forum. Many people use smokeless loads without any noticeable issues but the arguments about increased wear and tear, parts failures, etc. can be entertaining to say the least. If you want to stick to what the gun was designed for use black powder loads and be sure to clean properly when done.
