Holdover, BDC Reticles or Turret Dialing
This image shows a mule deer buck standing broadside, illustrating how a sight would be held over its withers tom compensate for bullet drop. BDC reticles accomplish this while allowing users to align a sub reticle at the spot where the bullet will land.
There's a new myth starting. It says that riflemen no longer have to deal with holdover thanks to BDC reticles and turret dialing. Let's nip this one in the bud, shall we?In the shooting world, holdover is commonly understood to mean aiming over your target in order to hit it. It's expressed as "Man, you'd better hold over. He's waaaay out there." Back in the days of open-sighted muzzle-loading rifles it was called a "coarse" aim or "seeing a lot of post." The more familiar phrase "Kentucky windage" refers to aiming into the wind to compensate for wind deflection, not holding over, but the concept is the same.When scopes became commonplace, shooters found it a lot easier to hold over because they could still clearly see their magnified target beneath the aiming point (crosshair.) The narrow, vertical line running down through the target made it easier to hold the proper sight picture left to right, too. "Put your vertical wire on its front leg and hold the horizontal wire just over its back" was common aiming advice.
Do BDC Reticles and Turret Dialing Really Eliminate Holdover?
This image depicts the reticles and sub-reticles of a BDC reticle, which has a confusion of small lines and dots along the vertical and horizontal cross wires.
The claim now is that turret dialing or selecting the correct sub-reticle on a BDC (Ballistic Drop Compensation) reticle enable hunters to hold dead-on. As a reader recently told me: "With laser rangefinders and BDC reticles, holdover is obsolete." Well, he's sort of right, depending on how you define the word "holdover."There's visual (line-of-sight) holdover and barrel (axis of bore) holdover. BDC reticles, dialing turrets, hyper-velocity bullets, laser rangefinders and the world's most efficient VLD bullets can eliminate the need for visual holdover, but not barrel holdover. Regardless your scope or sighting system, in the world of Newtonian physics, holdover remains necessary at any distance because gravity begins pulling bullets down the instant they leave the barrel. Once you think about it, this is one of those "duh" moments, but we get so enthralled with our gadgets that we sometimes don't think that way. So, at the risk of belaboring the obvious, I will belabor the obvious... just to more accurately focus our shooting perceptions.
Belaboring the Obvious: BDC Reticles Don't Eliminate Holdover
A barrel aimed perfectly level at a target 100 yards away will not put a bullet precisely on that target because gravity will pull the bullet below it. It doesn't matter how fast the bullet flies or how ballistically efficient it is. It will land low because gravity pulls it at an accelerating velocity of 32 feet per second. So, unless that bullet is flying at the speed of light, it's going to drop at least a trifle. What might surprise you is how much that trifle is: Aimed dead level at the bullseye, a 140-grain bullet with a BC of .625 and MV of 3,400 fps strikes 1.96-inches low at 100 yards. It's 7.7 inches low at 200 yards and 17.66 inches down at 300 yards.The need to offset this drop is partly why we have sights that stick up above our barrels. Those high front posts and elevated scope bases give us the room to angle our barrels up through our line-of-sight. This angle is so small that it's tough to spot when aiming modern, high-velocity centerfires at typical hunting ranges, but it's always there. Extreme-range shooters will often mount scopes with a 10- to 20-degree riser under the rear ring to angle barrels and extend scope turret adjustment range even more.
Why BDC Reticles and Turret Dials Make Holdover Seem Obsolete
BDC reticles are many, but the most versatile may be Hollands ART depicted in this photo.
With visual and barrel holdover definitions clarified, we can more clearly understand what many shooters mean by "holdover is obsolete." They mean the need for a visual holdover is obsolete. BDC reticles allow you to hold one of their many sub-reticles right where you want your bullets to land IF you know the precise distance to the target (laser rangefinders handle this) and which sub-reticle corresponds to that distance. Wind deflection must also be accounted for. If there aren't precise windage reticles on the sub-reticle chosen, Kentucky windage must still be used. But the next time you select a long range sub-reticle in a BDC scope, take time to notice where the central crosshair is hovering: over your target. You are still employing barrel holdover. With the sub-reticle you're just able to do it more precisely by holding that sub-reticle right where you want your bullet to land. Arguably the most versatile BDC reticle is the Holland ART, Advanced Reticle Technology. Infinitely versatile, it works with any rifle, any cartridge, any bullet, anywhere.
Holdover, Like Taxes, Stays With Us, BDC Reticles or Not
With a turret dialing system, you dial your scope's elevation turret to position the crosshair for a dead-on hold. Both these systems, by the way, result in creating the same barrel holdover we've always used to hit distant targets. Until we start shooting guided missiles with their own power source, we'll continue employing some form of holdover to make downrange hits.We'll cover BDC reticles and turret dials for long range shooting in a future post here on Ronspomeroutdoors.com. If you don't want to miss any posts, sign up for our newsletter. And let us know which hunting and shooting topics you'd like to see addressed. We don't know everything about shooting, hunting, guns, ammo and ballistics, but, given enough time, we can usually figure it out.Author Ron Spomer learned holdover and Kentucky windage while hunting jackrabbits with an open-sight 22 rimfire in the frozen farm fields of his youth. "Just hold two jacks over and one into the wind!"
