Best Zero for .243 (Sighting in Right)

It’s no secret that I love the .243 Winchester caliber rifle cartridge. But to use it to its maximum effectiveness, you’ll need to sight in your .243 to the best zero distance for your intended use. What does that mean?

Best Zero for .243

What’s the best zero for .243? The best zero distance for a .243 Winchester is 25 yards. At 25 yards, a 100 grain, 2960 fps, .243 bullet will have a maximum point blank range of 296 yards and hit roughly 3″ high (2.7″) at 100 yards. This 25 yard zero will allow you to aim dead on target all the way out to 300 yards.

NOTE: in this example, I used a 6.75″ target size to make the math work out, because a 6″ target size changes the “best” zero for a .243 Winchester to 26 yards. And precious few of us have access to a “26” yard range.

Some Definitions

But this is only part of the story, because so many factors go into .243 bullet trajectory that it’s never as simple as that. So let’s define some concepts first.

Stick with me here, because sighting in any rifle is not trivial and there are some concepts that you need to understand.

What does Zero mean? “Zero distance” is setting your sights or scope crosshairs so that your point of aim is the same as your bullet’s point of impact at a given distance to your target.

Bluntly, at zero distance, your bullet will hit dead center where you’re aiming.

What is MPBR (Maximum Point Blank Range)? Maximum point-blank range (MPBR) is the distance (in yards) a projectile (bullet) can travel without rising or falling more than a predetermined measurement above or below the point of aim. For most North American big game, from white-tailed deer to moose, an acceptable trajectory allowance is 6″ (up or down 3″ from the point of aim)

Whew, that’s a mouthful…

The reason we want to figure out that MPBR is so that we know that out to a given distance, we don’t need any fancy dials or trajectory charts to help us kill game. We can simply hold “dead on” and shoot, being reasonably sure that our bullet will, at most, hit 3 inches high or low along its entire pathway out to the maximum point blank range.

So from 0-300 yards, for instance, we aim at the dead center of the kill zone on a deer, and no matter how far it is away, we’ll hit the vital areas.

And that’s a small enough margin for error to make quick clean kills on most North American big game.

Other factors that influence bullet trajectory:

Look up any ballistics calculator and you’ll find of host of settings and entries you must fill out to get the most accurate bullet trajectory reading/information for a given bullet/cartridge.

For this discussion, I’ve used the 100 grain, .243 cartridge and baseline entries of:

  • Bullet Style – Soft Point
  • Bullet Weight – 100 Grain
  • Muzzle Velocity – 2960 feet per second (fps)
  • G1 Ballistic coefficient – .355
  • Sight Height – 1.5″
  • Zero Ranges – 25, 50, and 100 yards
  • Wind Speed – 10 mph
  • Range increments – 25 yards
  • Altitude – 0 ft. above sea level

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Sighting in a .243

My uncle, love him as I do, used a 10 inch white pie plate to sight in his 7mm. And once he got on that pie plate, he called it good and went hunting. I can’t fault him for it though, because say what you will about his sighting in methodology, the guy killed deer.

The “proof was in the puddin’ ” as they say.

My father the “Colonel” on the other hand… Well, let’s just say that 22 years as an Army officer in the Infantry left him with some hard and rigid rules about zeroing rifles. And I guess when your life depends on rifle accuracy, you learn how to make a rifle accurate.

After my own trip through bootcamp, I learned that there are precious few instances when you’ll need anything beyond a 25 yard zero, even for a .243.

10 Steps to Sighting in a .243 Rifle

I’ve written a more in-depth description on how to sight in a rifle in another article. So if these terms below are unfamiliar to you, you can read that article and get some clarification.

  • Step 1 – Install your rifle scope properly and securely
  • Step 2 – Adjust the scope to the proper eye relief (distance from your shooting eye to the rear of the scope)
  • Step 3 – Make sure the rifle and crosshair reticle are level
  • Step 4 – Bore sight your rifle and scope
  • Step 5 – Fire a 3-round group at 25 yards to find your starting point of impact
  • Step 6 – Adjust the scope settings to move the point of impact to zero
  • Step 7 – Fire 3 more rounds at 25 yards to test
  • Step 8 – Adjust the scope settings again if need be
  • Step 9 – Fire another 3-round group at 100 yards
  • Step 10 – Fine tune the scope crosshairs to make the bullet point of impact 2.7″ at 100 yards

Sighting in a .243 at 25 Yards

As I mentioned earlier, a 25 yard zero for a .243 is just about the best zero you can have for practical hunting purposes.

Here’s why.

With a 25 yard zero, out to 300 yards, the .243 doesn’t travel above or bleow your line of sight by more than 3″. It also maintains enough kinetic energy (killing power), to remain an ethical and effective deer hunting bullet at that distance.

Beyond that 300 (296) yard distance, the trajectory of the little 100 grain, .243 bullet starts to drop more rapidly and its kinetic energy falls below 1,000 ft. lbs. at about 325 yards.

Because of this, I’d suggest that the farthest range you should attempt to kill deer-sized animals with a 100 grain .243 bullet is 400 yards. And at that distance, you’d better be looking at a broadside animal that’s not moving, because the kinetic energy of your 100 grain .243 bullet is down to 880 ft. lbs.

And I only say that, because I’ve seen enough deer dropped hard at between 300 and 400 yards that the theoretical limits are not matching up to their practical application.

That said, let’s take a look at a couple of other popular zero distances for the .243.

Sighting in a .243 at 50 Yards

The problem with a 50 yard zero for a .243 is that the MBPR falls off pretty significantly. MPBR goes down to around 225 yards, at which point the point of impact is -4.0″ which is beyond our +-3″ impact for a 6″ target rule to find our MPBR.

So with a 50 yard zero on a .243, you’d only be able to aim dead on out to 225 yards. Not what we’re after.


Sighting in a .243 at 100 Yards

What about a 100 yard zero on a .243? After all, this is the distance that most rifle ranges are geared to let you practice.

With a 100 yard zero for a .243, you’d think that things would get better … and you’d be wrong.

If you sight in your .243 for 100 yards, its MBPR will drop to 200 yards. Because at that distance the point of impact is -3.3″. Any farther, the bullet drops to -5.0″ at 225, which would result in either a miss of a very low hit on deer-sized vital areas.

Best Zero for .243 Wrap Up

So, pretty universally, shooting 100 grain ammunition and using it to hunt for deer, the best zero for .243 Winchester rifle would be 25 yards. At that distance you’d be able to get the best maximum point blank range in yardage of around 300 yards (296). This would allow you to aim dead on at animals out to 300 yards and still hit vital areas.

Steve W

Steve has been a hunting junkie his entire life. Once his daughters were able to go hunting, he relearned why he love hunting so much. Since then, he's taught them everything he learned from his own father about hunting and why hunters hunt.

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