Usually 3 strikes to roll a stamp over a rounded surface that won't allow it to imprint in one wack, or doing a large imprint stamp onto a flat surface .
The style of cut of the stamp makes some much harder to use than others. Some imprint the background into the metal, leaving the figure standing. Those are particularly difficult to hand stamp as a tremendous amount of metal has to be displaced. They are easier to make as the figure is simply cut out instead of relief cut, but much harder for the user to punch into place. I've seen some of the English stamps made this way
Use a large hammer, one that you can confortable handle. You don't want to have to raise it much higher than the back of your head and then come down squarely on the stamp. If you need to raise it farther back to get more force,,the hammer is too light. The farther you have to raise it, the more off the mark your hammer strike can be. If the hammer is too heavy to lift, you'll have the same accuracy problem when trying to strike the stamp.
I usually put a piece of tape on the surface where I want the stamp to be. That'll be the bottom edge of the imprint. Not as important in proof marks and the like but it gives you something to work off of if you're like me and has to get in close to see correctly.
Place the stamp down (oriented top/bottom correctly of course!) on the surface and pull the bottom edge up against the edge of the masking tape you laid down.
Now roll one the stamp up one one edge,,either right or left,,does make a difference.
Stamp that edge into the metal. You should have approx 1/3 of the image in place and a nice depth at that.
Replace very carefully the stamp into the imprint at the same angle it was struck. You must make sure it is correctly seated again.
Now roll it back to the upright position and strike it again. That imprints the 2nd 1/3 of the print on a rounded surface,,it will imprint the entire image on a flat surface (but not very deeply).
Roll over to the other side and complete the last 1/3.
After you do a bunch of these, you can do them w/o ever lifting the stamp from the metal. A quick 1,2,3 as you roll the stamp over from one side to the other on the rounded surface.
Vibration or 'give' in your set-up is your worst enemy. The part must be dead solid when struck. Bounce-back is commonly seen in hand stamp markings. That double image thing. It can be from the impact of the stamp,,the part recoiling and bouncing back and restriking the stamp again. Or too light a hammer bouncing off the stamp after punching it and restriking it a second time.
Careful w/barrels. It's easy to imprint the metal and have it show on the inside. Many M/Loader bbls are softer steels. Muskets can be thin. It's easy to 'make your mark' on the inside,,not that it's going to be seen too easily. It's just something you don't want to do.
(I will always remember the imported O/U shotguns in one custom shop I worked in in the 70's that were refused because everyone had their bbl marking so heavily imprinted they could be seen inside the bores.)
Filling the bore with Cerro-Safe helps with deadening the strike & any vibration for a nicer imprint, but it does not lessen the chance of a signiture of your work on the inside of the bore if you get carried away.
Wear safety glasses... stamps are file hard. They can chip and chatter, I've had them escape and fly away right out of my gnarly digits too when struck. I'm still missing a 7.
