The Russian Mosin Nagant Forum

I recently purchased a New England Westinghouse rifle (see pics). It is stamped 1915 and with what I understand as experimental marks of an eagle head with each number #1, 4, 5, 7 under each head. So, could possibly be a surcharge US or expeditionary forces. Every search on the web is a Nagant 1891 or M91, but nothing looks like or matches this gun. It seems newer to me but stamps look legit (hope its not a good fake) There is no SA marking identifying it as Finnish, so should not have been reworked. Serial numbers all match including bolt, however there is not one stamped on trigger guard. There is a notch in the stock and screw holes in receiver for possibly a scout scope or side attached sight? (Would like to know what's missing).The crest logo appears to have all feathers pointing up with diamond on breast. There is no caliber reference anywhere on rifle. No sling attachments, nothing resembles a nagant.
Any info would be greatly appreciated!

The poor thing was sporterized. Unfortunately collector value is nil, but it should be a good shooter.

Higher quality of sporterizing than I am used to seeing, looks like it even had a peep sight attached to the side of the receiver at one time. Unfortunate this was done, but there is nothing that can be done about it now probably 60 or more years later. Just shoot it and enjoy it as it is. From what I see the issue will be that you have no rear sight on there, maybe no front one also? You will have to seek out a replacement commercial rear sight Who made these? Anyone remember, I am having a senior moment trying to remember the name.