This is a Savage model 87 series, 66C, 5 series, 6 series, and early 187 (no letter) inside magazine tube in .22 long rifle. It is a reproduction made exactly like the original. The brass tube alone measures 18 1/4" and 18 7/8" over the knerled tip to the end of the brass tube (not counting the follower).
It also fits the following models: Savage 5, 5A, 5B, 6A, 6AB, 6B, 6C, and 6D. Stevens & Springfield models 187, 87A, 87AB, 87AT, 87B, 87C, 87D, 76A, and 87K.
PLEASE NOTE: If your outside magazine tube measures 17 7/8" you need the tube found here as they made a few guns with a 1" short inner and outer magazine tube without modifying the model number or letter.