Most American is very subjective. With that said on pure numbers alone it would be .22LR, 30-30, 30-06, 45 Colt, 12ga
But do pure numbers make it the most American?
IMO, no it's not the numbers. Obviously the 06 isn't AS popular as it WAS for DECADES.
I'd agree with whoever said the 308 is seeing more use today than the 06. What about 'collectively' over the years ? that's another question. However the 308 is @ 1/2 the age of the 06.
We have many American proprietary cartridges and I'm GLAD.
The
270 Win certainly IS American w/o Question.
Maybe it's my "maturity"
, aka age, but when asked or someone mentions 30-06 >>> WW I, WW II, Korea, etc. comes to MY mind.
AMERICAN? Yes Indeed.
Jerry
