Parker SN 1500 (c. 1878) - 4200 (c. 1884) patterning was done at 45 yards in a 18 x 24 oval or possibly a rectangle. Between SNs 4500 and 86000 patterning was at 45 yards in a 24" circle.
After 1896, Parker used the standard 40 yards in a 30" circle. (Courtesy of Chuck Bishop)
12g Parker SN 71792 c. 1891 was patterned with 1 1/4 oz. No. 7 and 42 grains (3 1/4 Drams) DuPont Bulk.
A 1900 Parker hang tag states that 12g 2 5/8” chambered guns were patterned at 40 yds. in a 30” circle using a 2 5/8” shell with 1 1/8 oz. No. 7 chilled shot and 40 grains ( 3 1/4 Drams) of DuPont Bulk Smokeless powder. (Courtesy of Bruce Day)
1920s tags listed both 1 1/8 oz. and 1 1/4 oz., still with DuPont Bulk Smokeless.
A 1924 16g was patterned with a 2 9/16” shell, 1 oz. No. 7 Tatham chilled shot (291 per oz.), and 2 1/2 Drams Bulk Smokeless.
A 1925 20g tag lists a 2 1/2” shell, 7/8 oz. No. 7, and 2 1/4 Bulk Smokeless.