The B2 custom stock is £15 from sportsmarketing. I really wouldn't reccomend using one of these for rabbits though. I have had one and am talking from experience. They are just not accurate enough to guarantee a head shot every time. I'd save up some money and buy a second hand BSA supersport or an Edgar brothers model 60, The latter is only £70 new, is 11.5 ft lbs and very accurate. second hand supersport will set you back about £50, maybe less.