The guys are all right. Some will shoot a little slower and some a little faster, at first. Also, some will be more accurate at first and others take a few shots to be more accurate. But, after the gun has been shot a few hundred times, they are faster and more accurate. The gun needs to re-break itself in. The new seal will contour to the compression tube better as the gun finds it's new way. I've had guys call after a week or so and say WOW!! what a difference. All of a sudden it just started shooting one hole targets and of course the gun is much smoother and quieter due to the tune. ALL air guns benefit from a tune. Whether I buy a new or used gun, it come down and gets a tune. It's always more of a pleasure to shoot and more accurate. The gun will also last much longer. Bought a new gun once and didn't tune it, it was junk in less than 100 shots due to a burr than ruined the cocking slot in the compression tube. The only true fix would have been a new receiver, which the manufacturer refused to do so I returned it to the retailer. In this case, if it ain't broke, it might soon be. Lee