BSA Commercial No1 Mk3.

[tiriaq]

Three sold at auction today in Canada. $650, $700, $900, plus commission and tax. Had been set up for competition. One had the extra band added behind the nosecap, so it probably had a packed barrel.
I have one, also set up for target shooting. Decent shooter, although the throat has cordite erosion.
It seems many of these rifles were used for target shooting.