I was once at a sniper match competing with a bunch of long-range shooting specialists, some of whom had no problem making first-round hits at 1,200 yards. Then we encountered a stage where we had to shoot tennis balls hanging from strings about 15 yards downrange--which some of these shooters couldn’t believe they were missing.
Here’s why. When shooters take on targets within 20 yards, bullets will impact low because the bullet has not yet met the line of sight of the optic. On a target at 3 yards, an MSR will shoot about 3 inches low, which can miss small targets like the head box on a standard IPSC target.
Shoot at a small black dot from distances of 3, 5, 10, 15, 20, and 25 yards and make note of your “come-ups.” Include that data on your range cards to make sure you’re ready for close-in shooting.