[saemetric]

I know Colt has I,J,D frames and S&W has N,K,L,X, and J. Which maker uses the F frame designation?

[KyJim]

I don't know who makes an F frame but SW also used to make an I frame.

[Virginian]

I think that was what Colt put on the Walker. Everyone who saw it excleimed F*** !