It is from the black powder era, so I would not advise any extensive firing with modern smokeless powder cartridges.
Howdy
Around the turn of the century, Iver Johnson redesigned their revolver line so they could safely shoot Smokeless Powder. Yours is not one of those.
There are three features that make it easy to differentiate between the Smokeless Iver Johnsons and the earlier Black Powder revolvers.
1. The little owl on the grips faces backwards.
2. The bolt stop notches on the cylinder have a hard edge both top and bottom.
3. If you remove the grips, the hammer spring will be a coil spring.
Here is a photo of an Iver Johnson Hammerless revolver from the Smokeless era exhibiting the three identifying features.
Here is an Iver Johnson revolver from the Black Powder era.
1. The little owl on the grips faces forward.
2. There is only one hard edge on the cylinder stop notches, the hand keeps the cylinder from rotating backwards.
3. The hammer spring is a leaf spring, as can be seen in one of your photos.
Although your revolver has most likely been fired with Smokeless ammo at some time, it is not recommended.
