Got my son set up for season. Have possible problem though. Were out shooting today and had him pass a couple bheads thru. He' s shootin 45 # out of an Impact extreme, w/ Rocket wolverines. Couldn' t see where heads were opening. He was shootin @ cardboard target w/ excelsior bale backing.Rubberbands were pushed back over the ridge on blades, indicating they opened.May target not have enough resistance, thus no blade marks. I don' t shoot them but see they are a bit more forgiving to slight form errors. He hits 5" circle out to 30 yds consistently( he won' t be going that extreme 20 max). Has anyone experienced this but had no problems on deer?Does it sound as though they aren' t opening due to lack of blade mark in cardboard?They open fairly easy by hand, I' m perplexed??!!!!! Thanx for any assistance or advice.