Most important firearm innovation

[A.M. Baer]

1 - John Moses Browning
2 - The Second Amendment
3 - Rifling
4 - metallic cartridge

 

[Dr. Tad Hussein Winslow]

Probably rifling, followed closely by the self-contained metallic cartridge.

 

[Gottahaveone]

Primers. Without them metallic cartridges would be nothing more then single-use powder horns, and forget about any semblance of multi-shot firearms.

Bingo. We can all be thankful to a duck hunting preacher