You want to put your metal over the dent and hammer it with the ball end of the ball peen hammer.
Cold forming sheet metal with a hammer.
This involves forming a feathering by hammering the edges of the sheet to about half their original thickness and then cutting slits at right angles to the edge.
For this example we will hammer form some tank end caps.
Move the metal around to get a smooth bowl shape.
This is a handy metal fabrication technique you need to learn.
And while it s not the only way to make a barrel for ar15 patterned rifles it is likely to be the most common.
The cold hammer forged marking chf is stamped into millions of rifle barrels around the world.
Lots of little hits will make your piece of metal take shape.