do not touch the krinkov on the JBB website with a barge pole, it is not an airsoft skirmishable weapon, but more of a backyard plinker wiht your mates.
Accuracy is down to a lot of different variables, primerley hop adjustment and bb quality (for goodness sake use profesional polished bb's in 0.2g and 0.25g weight, cheap .12g will destroy your internals). This can then be made more accurate by fitting tightbore barrels and the like, rate of fire can be altered as well, but to start with buy a decent quality gun and adjust the hop. The amount of rentals I have helped out by a simple hop adjustment to the site guns is ridiculous over the years.