Ross Mark II**
You have a good rifle there. The Ross Mark II** was developed as a target rifle, and was available with several options. You have a stamped rear sight base, but a milled rear sight base was also fitted to this rifle.
This is the rifle that Sir Charles Ross thought about as to what he would like for a Target rifle. It has a heavier barrel, with 16 threads per inch instead of the Military 3 thread per inch barrel. As stated, your rifle was intended for the shooter to supply the rear sight. Some Mark II** rifles did not have the rear sight mounted on the barrel, and had a wood top guard that was solid.
Commercial Ross rifles have a serial number, about 1/8 inch letters, on the left side of the barrel, just ahead of the receiver. Military Mark II** rifles do not have these serial numbers.
This was the rifle that the Canadians ruled Bisley for about five years, from about 1908 to 1913. The British objected to several points on the rifle, as it was supposed to be a "Service Rifle". The front sight hood, the absence of a bayonet lug, and other points were brought up. These were addressed by Ross, and later rifles had bayonet lugs, etc.
A 1910 Ross sight will fit on the mount. The original sight aperture hole was smaller than the later 1910 aperture hole.
A good find on your part. Not too common compared to the 1905 Mark II production.
R.S.A. is the Royal School of Artillery, a Canadian Unit.
.
.
.
