The Firing Line Forums - View Single Post - DOUBLE TAP DEFENSE derringer range reports?

Ljutic · November 16, 2013, 12:06 PM

Morning Biff.

I always had a concern that when firing one barrel, the other firing pin would place a witness mark on the primer of the unfired round. The photo below shows a fired case in the lower barrel and an unfired round in the top barrel with a witness mark left by the upper firing pin during recoil. I understand that Derringers leave witness marks on the primer of the unfired round, but to me these witness marks seemed excessively deep and strong. Strong enough to ignite the primer.

The photo below shows 4 recovered brass cases from my last trip out with the DoubleTap. Two fired normally and two fired at the same time. To me, the primer marks look virtually identical on all four brass cases. By design the DoubleTap hammer only contacts one firing pin at a time so the other firing pin must have been driven forward by recoil alone.

It's obvious to me that the firing pins have some measure of float and will move forward under recoil and not just when struck by the hammer. If they didn't float, we wouldn't see witness marks on the unfired primer. Before I would own another DoubleTap, I would need to see no witness marks left on the primers of unfired rounds.

Thanks for the comments about the review and I hope I provided the information you were looking for. If not, please let me know.

November 16, 2013, 12:06 PM	#12
Ljutic Junior Member Join Date: August 4, 2009 Location: Arkansas Posts: 5	Morning Biff. I always had a concern that when firing one barrel, the other firing pin would place a witness mark on the primer of the unfired round. The photo below shows a fired case in the lower barrel and an unfired round in the top barrel with a witness mark left by the upper firing pin during recoil. I understand that Derringers leave witness marks on the primer of the unfired round, but to me these witness marks seemed excessively deep and strong. Strong enough to ignite the primer. The photo below shows 4 recovered brass cases from my last trip out with the DoubleTap. Two fired normally and two fired at the same time. To me, the primer marks look virtually identical on all four brass cases. By design the DoubleTap hammer only contacts one firing pin at a time so the other firing pin must have been driven forward by recoil alone. It's obvious to me that the firing pins have some measure of float and will move forward under recoil and not just when struck by the hammer. If they didn't float, we wouldn't see witness marks on the unfired primer. Before I would own another DoubleTap, I would need to see no witness marks left on the primers of unfired rounds. Thanks for the comments about the review and I hope I provided the information you were looking for. If not, please let me know.