Standing unsupported shooting: either target style with a heavy rifle all braced up, or sporting style with a light weight rifle. The latter really demands a total weight under 8 lbs. Those who can shoot sporting with a heavier rifle are either really "rifle" fit or big solid strong chaps. Balance makes a difference too with either neutral or most of the weight towards the rear. Two styles to control the heft in different ways.

To tame spring rifles the the heavier the better and the smoother the better. Rifles that are good for one good shot are usually on the too heavy side for long plinking sessions shooting standing unsupported sporting style.

Just saying as I like my unsupported plinking and use a FWB Sport, Webley Omega and a HW95, all three in the 71/2 lbs park before adding a light weight scope. These rifles behave better unsupported than they do when held to a bench as they can breath. Well all the spring harmonics are more consistent unsupported. Well I think so.

Lastly when shooting sporting unsupported I shoot fast and smoothly with a low powered scope, usually a 4x40. And keep the range down to 20m or so. Little gained from holding the aim too long trying to get perfection.