Yup it's a rimfire. 1919,1922,23A,23AA, and most M-19s were rimfire.

23B 25-20,23C 32-20,23D 22 Hornet and there were M-19 Hornets as well.

B & C were made in both slow lock and speed lock, Ds and M-19 speed lock only.

Don't buy a repro 23A magazine as they are junk.

Here's a correct one on Ebay that will probably bring $150, of course you could buy a whole beater 23A w/magazine for that price.

http://www.ebay.com/itm/Savage-23A-19-NRA-Magazine-/141898259220?hash=item2109cb9b14:g:klcAAOSwPc9Wt-VR

NOTE: in rereading the original post, he may have an M-19 speed lock. Magazines for them are quite common.

OP how about a pic of the action ?

Last edited by spalding; 02/08/16.