Atmos Serial Numbers
Caliber / Model
519
532
522
526-5
526-6, 528
540's
Serial Number
25,000-59,000
Unknown, identical to Model 522
60,000-69,999
70,000-107,000
107,001-599,999
600,000 and up
Approximate Year Manufactured
Late 1940's to 1950's
Unknown, only a few manufactured
1950's
1950's
1960-1980
1980 -1998