I didnt realise free recoiling wasn't allowed..
It's a matter of semantics.
The rules say the following in the main (conventional High Power Rifle) portion:
5.3 Position of Rifle Butt
...the butt of the rifle must be held against the front of the shoulder on the outside of the shooting coat or shirt...
then again in section 22 (F-class specific):
3.4 (a)(3) and (b)(2)
...The rifle must be fired in the prone position from the shoulder of the competitor...
5.6.1 Positions
F-Class Prone is fired in the prone position from the shoulder.
Note that there is *no* mention of free-recoil, for or against, anywhere.
One interpretation of the rules (as written) is that 'fired from the shoulder' means as opposed to say, a specialty single shot handgun.
Even if a person were to invoke rule
3.18 General and it's mention of the 'spirit' and/or intent of the rules... it specifically addresses
devices or equipment, not methods or techniques.
Functionally... if a person were to push the gun forward, and then relax their shoulder ever so slightly rather than explicitly maintaining pressure against the butt plate... they get the same effect as free-recoil. They may or may not be pushing against the butt... and the only way you're ever going to know would be to go down the line, and stick a feeler gauge between their shoulder and the gun, while they're trying to shoot. Good luck with that. Maybe create a new rule requiring a pressure sensor in the butt plate that only allows the gun to fire if a specific amount of contact is present. The way the NRA HP committee as been with rules lately, either one is possible.
Personally, I think it's an idiotic issue. AFAIK, nobody is out there openly letting the gun take a 1/2" or more of a run at their shoulder. Even if they were, all someone has to do is wear a loose fitting shirt and you'll never be able to prove it. Find something better to argue about.