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The bolts are simple, an M1917 is small face and P14 is very large. You must have a cartridge to see if it will fit...they are shaped the same.

The two last pics clearly show you that one at least is marked to caliber .303. If this is the rifle you ask about then...yes, .303.

The one that looks jumbled is "Notenglishmade", all in one line. Because it wasn't. Second and third pic.