Sort of yes. They are the same physical size. Trouble is the foil is much thicker-harder than a pistol primer, so your pistol might not have the oomph to fire it. Also, there is more primer compound in them. They will fire with more vigor and could maybe give you some pressure issues if you have loads on the high margin. My first recommendation would be to sell or trade them for the correct ones. If that does not float your boat load a small number cases without a charge or bullet and see if you pistol will fire them. All that being said, it is a bad idea. Maybe not a critically bad idea, but a bad idea nevertheless.