I believe the OP (Sven) also had the older rules wrt the Prone position.
This is what I believe to be the current rule:
8.9. PRONE – (which may be used in the “Free” position) The Shooter lays face down. The shooter’s forearm,
from elbow to fingertips must be clear of any artificial or natural support. However, a sling as described
in rule may be in contact with the shooter’s forearm in order to help steady their arm.
As this refers to the ''Free" position, see 8.8 below:
8.8.FREE POSITION - The shooter may use any shooting position that is safe and comfortable to the shooter.
No other means of support, other than the shooter, shall be used for the rifle or body. The rifle cannot
contact the ground.
No body straps are allowed.
a. A shooting position where there shall be only 3 points of contact with the ground (2 feet and 1 knee).
Definition of use in English:
1.Take, hold, or deploy (something) as a means of accomplishing or achieving something; employ.
(from Oxford Living dictionaries - https://en.oxforddictionaries.com/definition/use
While the use of a hamster is perfectly legal and included in the rules, it will not be allowed to 'touch the ground' according to 8.8 as it becomes part of the rifle when connected. perfectly acceptable to use it while sitting (ie 8.8 'Free' - no touching the ground) or kneeling (refer to 8.6 - only 3 points of contact = 2 feet and 1 knee), so one cannot compare the hamster to a bi-pod.
The bipod is allowed only for giving your rifle something to rest on/balance when not in use, simple straight forward and easy.
Remember that the rules are a set of guidelines and are not there for everyone to nit-pick and try and find loopholes. A certain amount of sanity and common (?) sense needs to prevail. I think Brian Samson said it very nicely in an much earlier thread, but I cannot find it now to refer back to.
In my opinion, once you enter the 'shooting zone' - the area where you take your shot from (see 2.1 I guess) and the timing starts (see 5.6) then the whole purpose of what you are doing is to take the shot/s, so that would be 'shooting'. You are then 'USING' your rifle and all its legally attached goodies for that purpose.
When you are awaiting your turn to shoot and your rifle and all its legally attached goodies is resting on the ground (pointing in safe direction down range), then surely your rifle is not 'IN USE' as you are not 'employing' the rifle at that point in time.
(Link to WFTF Core rules - http://www.wftc2016.com/OfficialSite...les%202016.pdf