I have 3 Challengers in 3 different barrel lengths. 4 1/2", 6", and 6 3/4". Originally I thought there were only 2 different lengths but I found a third. I'm not sure if the barrels and frames are matches.
The 4 1/2" has manufactured date of 1965 with stamps on the
left side
BROWNING ARMS COMPANY
ST LOUIS Mo & MONTREAL P.Q.
and right side
MADE IN BELGIUM
22 LONG RIFLE
The 6" has manufactured date of 1964 with stamps on the
left side
FABRIGUE NATIONALE D'ARMES DE GUERRE
HERSTAL - BELGIQUE
and right side
BROWNING'S PATENT DESPOSE.
22 LONG RIFLE
The 6 3/4" has manufactured date of 1970 with stamps on the
left side
BROWNING ARMS COMPANY
and right side
MADE IN BELGIUM
22 LONG RIFLE
The 4 1/2" has manufactured date of 1965 with stamps on the
left side
BROWNING ARMS COMPANY
ST LOUIS Mo & MONTREAL P.Q.
and right side
MADE IN BELGIUM
22 LONG RIFLE
The 6" has manufactured date of 1964 with stamps on the
left side
FABRIGUE NATIONALE D'ARMES DE GUERRE
HERSTAL - BELGIQUE
and right side
BROWNING'S PATENT DESPOSE.
22 LONG RIFLE
The 6 3/4" has manufactured date of 1970 with stamps on the
left side
BROWNING ARMS COMPANY
and right side
MADE IN BELGIUM
22 LONG RIFLE