Red Navy M1891/30?!

[Mosin Shooter]

After having my M91/30 since Christmas, I was looking over the stock, hugging the rifle(taking my Mosinitis medication), and I noticed the Cryllic letter ф, forward of the magazine, under the gun,which is also the same letter seen on the Soviet Navy insignia:
The International Encyclopedia of Uniform and Rank Insignia around the World.

Is it possible that my M91/30 was used by the Red Navy Guards?

I found other marking to among them,2 Cryllic letter Л's in circles on the stock just behind the cocking piece,БЅ behind the trigger guard,я,К,И in stamped in circles on the left side of the shoulder stock and 3,Б and Ь stamped in circles on the right side of the stock. Lastly there is a large letter И behind the sling estucheon.

[SwedeSteve]

Again look at: 7.62x54r.net Guide to proofs and Markings. Understand though, a lot of stock cartouches are just the maker's mark, refurb marks, or are just not known.