Used as front base on these rifles:
Ithaca LSA-55. LSA-65, Shilen Flat Top Reciever
 
Used are rear base on these rifles:
Anschutz 1568, CIL 950, 950C, Ithaca LSA-55, LSA-65, Savage 110, 111, 112R, 112V, 110E, 110S, Shilen flat top receiver
Stevens 110E