you are breathing all wrong, your trigger control is all wrong, and your body positioning; you are in incorrect unnatural, or a nonrelaxed oscillating position; that is to say, you are not in a correct,natural, relaxed, static position, so your muscles all over your body are twitchin and bouncin, trying to hold your aim, while fighting against, an unnatural , unrelaxed, position.
you can overcome a lot of bad crap at the range, almost all of it, but bad trigger control, and bad body positioning, especially together , is almost impossible to overcome.
Natural body position is mostly this; say you are going to be shooting off of a bench. Get all totally ready- all your stuff, ammo, bags, front and back, rifle rested on it, mags loaded, 1 in the gun, just like you are ready to go, then put your finger on the trigger, and do everything you normally would, if you were going to pull that trigger. THEN DON'T!!!! drop your trigger hand on the table, close your eyes, let your head totally droop on your neck, with your chin resting on your chest, and breathe normal. As a matter of fact, when you do this, remember your breathing during this time; this is normal and natural, and should be this way, all through your shooting period.
Sit there for at least 30 seconds, totally relaxed; if you can wait a full minute, that is better. Then open your eyes, look up, look through your sights or scope, WITHOUT MOVING, ADJUSTING, FIDGITING, FIXING, MOVING YOUR A$%SSGROOVE, NO MOVING AT ALL!!!! Keep your body in it's totally relaxed mode, just as you had it, with your eyes closed, arms down, hands down, chin on chest, just now that your eyes are open, and head is up.
Now then, if you have to move any part of your body, to correctly look through your scope, or you have to move closer, or a little left or right, or tilt your head, or move your head on your neck, a little left or right, or whatever the movement is; YOU ARE NOT IN A NATURAL SHOOTING POSITION!!!!
you should be able to open your eyes, lift your head, raise your shooting hand, and without moving anything else at all, be ready to shoot; if not, and you have to move a bit, strain, here a bit, stretch there a bit, then your body is twitching all over, and your muscles are fighting to keep your potato lumpy skin and skeleton where the muscles want them to go.
As for the breathing keep up the regular normal breathing, and allways choose a place , on the way of the exhale, where to pull the trigger; allways
the same place.
