It would be hard to say what your rifle is worth. You have what looks like a New England Westinghouse M91. All N.E.W.s were dated 1915, marked 1915r. The r stands for year. The barrel shank should look like this.
One that is all original and in good shape will bring top dollar. The ones that are all original never left the US and are still hard to find.
Here are a few of the M91s in my collection. I have added a few more since this pic was taken. The rifles cost me from $75 to $200.
The 4th rifle in the pic is an all original US property marked N.E.W M91.
From top to bottom:
#1 New England Westinghouse, SCW, dice mark.
#2 New England Westinghouse, Finn marked.
#3 New England Westinghouse, Finn marked, SN# 1911A.
#4 New England Westinghouse, US Property marked.
#5 Remington 1916 Finn marked.
#6 1899 Tula Imperial 1st pattern. SCW.
#7 1916 Tula "Perter The Great" Imperial.
#8 1916 Sestorryetsk Imperial.
These days most M91s are going for $150 to $250.
Here are some pics of a Finn marked M91 that I picked up for $150