I think it depends on how much caffine your used to. I am a caffine addict, drink a pot of coffee in the morning and go from that right into Mtn. Dew, probably 5-6 cans a day and then a couple cups of coffee after supper. With that said, I have no trouble focusing on my target and drive nails at 200 yards with the 7mm and with the Mathews Drenalin (lol) at 30 yards. I'm pretty sure I would shoot worse without