I fully concur with you. The P.13/P.14/M1917 rifle is one of the most underrated rifles, if not THE most underrated rifle at all. I think its poor fate is mainly based upon the fact that it is British engineered (P.13 origin), but US made, so neither the British were happy to get a foreign made rifle, nor the US to use a foreign engineered rifle. But to name a few facts:
- if not WWI had ended, the US Army would had introduced the 1918 sniper rifle, which was invented by Winchester and based on the 1917 action
- it turned out to be one of the best sniper rifles the British had in WWI, no surprise many inter-war experiments were based on the same rifle action (Ainley rifle, detachable magazine)
- new sniper rifles were set up with the WWI sniper mount for Ireland prior WWII
- the British originally even considered the P.14 rifle with the No. 32 scope mount as official sniper rifle at the beginning of WWII
- it was produced as 1934 rifle for other countries as well
- it even was adopted for the Pedersen Device
- there were experiments and serial conversions with other calibers, such as 8x57 (Spain?), .22 lr (Parker-Hale and Denmark post WWII), 7.92mm/.303 rimless, etc.
- the action was so strong, it was very commonly used for high power cartridges Big Five hunting rifles for Africa
- Alexander Martin converted 421 of these rifles as sniper rifles for WWII, and the initial order was for even more of them
- Austria post WWII made experiments with the M1917 rifle converting it to M1917A4 configuration (with the Weaver M73B1 and Redfield mount from the M1903A4)
- Denmark/Greenland still uses this rifle nowadays with their sledge patrol - I can't remember another rifle being this long in service!
... and a hundred more reasons! I guess my passion for these rifles now is a bit obvious.