I believe that these refer to the barrel/actions only. For instance the 1907 Standard rifle and 1912 Sport rifle use the same barrel/action (marked 1907). The 1913 uses the smae action and trigger, but a slightly heavier barrel (690mm long x 24mm diameter) against 660mm long x 22mm diamater for the 1907. It's just a slighly more precise terminology.
The 2013 and 2007 can be bought with the same length/weight barrel as the 1913 and 1907, or with a shorter 500mm barrel. The shorter barrel has an aluminium extension tube that brings the sight radius back to normal.
Tim S
Exeter UK
What attributes of rifle appropriate for 3P?
Moderators: pilkguns, Marcus, m1963, David Levene, Spencer