my buddy won a marlin xl7 270.we got it on paper then went home,the next few days shooting off a lead sled at 100 yrds it cut two bullet holes 1 inch high.the third went couple inches to 1100 ocloc or so,now we sit around for 5 ten minutes or so shoot 3 shot group,now there opened up a couple inches, third shot walked a couple inches.would this be barrel heating up?rifle is shooting 150 grn factory win ammo.but the next day it ll cut two bullet holes off a lead sled.but like i said the third shot walks a couple inches.i seen a lot of high dollar guns do this too.saures,brownings,remingtons 700.win 70s.some just took more shots is all.what do ya guys think?reloads?