If you look on Weaver's web site there is a listing of all rifles and the various 2 piece, rails etc that fit them. Says the M15 front and back. 16s fit the model 64 rimfire
https://www.weaveroptics.com/w-mount-charts.html
B-MAG (WSM ALL CALIBERS) 15M
(48015)
15M
(48015) 48480 602 (48305)
B-SERIES (RIM FIRE ALL CALIBERS) 15M
(48015)
15M
(48015) 48480 606 (48309)
93R17,MARK I, MARK II, CUB 5,26 16
(48016)
16
(48016) 601 (48304)
64 16
(48016)
16
(48016) 603 (48306)