Re: F class for varmint rigs
In New Zealand and I assume elsewhere the two officially recognised classes are F-Class Open Class, and F-T/R (F-Class Target Rifle Class).
However this year during the National Rifle Association of New Zealand F-Class champs held in March we added two unofficial club-level classes; F Class Tactical/Hunter Open and F Class Tactical/Hunter Production (223/308). This was to allow shooters with rifles in more of a tactical, long range hunting, or varmint configuration to compete against similar rifles. All such rifles could only shoot from a bi-pod or backpack. Rear bags were permitted. All such rifles had to have a magazine and shooters were permitted to either fed manually or fed from the magazine. The number of rounds fired, the range distances shot, & targets were the same as the two official classes; the only difference was the equipment.
Winning Rifles in each Class were:
F-Class Open: Barnard in 284Win
F/TR: Barnard in .308
Tach/Hunt Open: Surgeon/AICS in 6.5mm08 AckImp
Tach/Hunt Prod: FNH A3G in .308
So I guess anything is possible if clubs / organisations are able to accommodate.