What weight recoil spring do I have?

Your current recoil spring weight can be determined by measuring the diameter of the spring wire with calipers. 

Spring Weight (in pounds) Conventional Coil Variable Coil
5 n/a .034
6 n/a .035
7 .038 .036
8 .038 .038
9 .040 .040
10 .041 .040
11 .042 .041
12 .042 .042
13 .043 .042
14 .043 .043
15 .045 .044
16 .045 n/a
16.5 n/a .045
17 .046 n/a
17.5 n/a .046
18.5 .047 .047
20 .047 .047
22 .048 .048
24 .050 n/a
26 .052 n/a