Here is a list of FX Bobcat Mark II O-ring sizes, quantities needed, and the parts numbers for Maryland Metric. They do not show the O-rings for .177 or the .25 but do for the .22 and .30 for the breach.
NBR 70
11354 4.0x1.5 qt. 1
10719 5.28x1.78 qt. 3
11377 6.0x2 qt.1
11394 7.5x2 qt. 1
10721 7.66x1.78 qt. 1.
11118 10.1x1.6 qt. 2
11452 11.0x1.5 qt. 1
10799 13.95x2.62 qt. 2
11551 18.0x4.0 qt. 2
11668 30x2 qt. 2
NBR 90
15831 2.5x1.5 qt. 2
15867 8x1 qt. 1
15687 9.3x2.4 qt. 2
16028 28x3 qt.1
NBR 70
11354 4.0x1.5 qt. 1
10719 5.28x1.78 qt. 3
11377 6.0x2 qt.1
11394 7.5x2 qt. 1
10721 7.66x1.78 qt. 1.
11118 10.1x1.6 qt. 2
11452 11.0x1.5 qt. 1
10799 13.95x2.62 qt. 2
11551 18.0x4.0 qt. 2
11668 30x2 qt. 2
NBR 90
15831 2.5x1.5 qt. 2
15867 8x1 qt. 1
15687 9.3x2.4 qt. 2
16028 28x3 qt.1
