I finally made it out to the range to get the new Ruger elephant-buster zeroed. My situation is probably pretty common these days: time and money are tight, and opportunities to shoot are limited. My nearest 100-yard range is an hour’s drive away, which means any meaningful shooting session takes up 3 or 4 hours, minimum.
In light of those circumstances and the generally tedious nature of sighting-in, I prepare as much as I can before I head out to the range and I work efficiently when I’m there. Here’s my advice on getting sighted-in fast’n'easy:
Chase the Gremlins Away
This bit should go without saying, but be sure to check any sight or scope mounting screws for proper tightness. If you’re shooting a bolt-action rifle, double-check the trigger guard screws, too. Loose screws equal frustration and wasted time/money/ammo at the range.
Then, even though you’re sure everything’s good and snug, bring the proper screwdrivers with you to the range. This works the same way that carrying an umbrella prevents rain: the only time you’ll need a screwdriver at the range will be the one day you forget to bring it with you.
Do Your Homework
I boresight the old-fashioned way, by looking down the bore and aligning the sights to match. I was going to type up a long description of the process, but Midway’s Larry Potterfield demonstrates it really well in this YouTube video. I do exactly what he does and it works very well.
Larry’s working with a scoped rifle in that video, but iron sights can be boresighted the same way. If you’re dealing with a gun that doesn’t allow sighting directly down the bore, I’d consider one of the laser-based boresighting gadgets that chambers like a regular cartridge.
Boresighting should put you within a few inches of zero at 25 yards. Usually you can get windage just about perfect, while elevation will almost always be a little low. That leads to the last thing you should do before heading to the range…
Do The Math
Boresighting will get you on the paper and reasonably close to a zero. You still need to figure out how to efficiently go from “reasonably close” to dead-on zeroed, though.
Scopes make this easy; most modern scopes have nice 1/4 MOA click adjustments. If you start shooting at 25 yards (and I recommend that you do), just remember that each click will move the point of impact about 1/16″, so if you’re 2 inches low, you need to come up 32 clicks.
Military-type iron sights also usually have nice click adjustments with each click producing a known change in point of impact (often 1/2 MOA). Sights on hunting rifles (like the NECG sight I’m using on my Ruger) often use simple adjustment screws without clicks or predetermined adjustment values. How are you to efficiently adjust sights like this? Here’s where the math comes in.
Remember high-school geometry and the properties of similar triangles? Yeah, me neither. Regardless, here’s the simple way of calculating how much you’d need to move the rear sight to produce a 1″ change in point of impact at 25 yards:
1" (the desired change) x (the sight movement required)
------------------------- = -------------------------------
900" (25 yards in inches) y (your sight radius in inches)
Measure your sight radius, plug it into the equation, then cross-multiply and divide to solve for x (remember how to do that? I had to stop and think). In my case, x worked out to 0.025″.
Keep in mind the old saying about theory and practice (in theory there’s no difference, but in practice…). This calculated value is an approximation, not gospel truth. It’s accurate enough to keep you from spraying shots all over the target as you blindly twirl the adjustment screws, but you’ll always have to fine-tune a bit.
Do all of this work at your leisure, from the comfort of home. Then you’ll be fully prepared when you can steal some free time and…
Actually Shoot the Damned Thing
I always start at 25 yards. Some folks go straight to 100, but (a) if your boresighting wasn’t perfect, you might well be off the paper, and (b) most rifles will be less than 2″ off at 100 yards from an initial 25-yard zero. Shoot off of sandbags or a proper benchrest set-up; you want to eliminate human error as much as possible.
Some people advocate firing 3- or 5-shot groups in between adjustments; in my opinion, that’s a waste of time and ammunition at this point in the process. Assuming you’re shooting from a good rest and you’re competent enough to trust your shooting and call any fliers, you can fire one shot and adjust accordingly, then fire another shot to confirm or re-adjust.
By way of example, here’s my 25-yard zeroing target. Round #1 was the first shot fired after boresighting at home; it was good for windage but 5″ low. I cranked the sight up about 1/8″ (the previously-calculated 0.025″ * 5″) and shot again; round #2 hit 1 3/4″ low. I dialed in 1/3 as much elevation as the first time, and round #3 was dead-on.
Why wasn’t the first adjustment perfect? Well, I could blame the gun, arguing that the first shot fouled the bore and burned off any lingering traces of oil, thereby throwing off its point of impact. And there’s certainly the possibility that I flinched or mashed the trigger a bit.
The most likely reason, though, is that I made the adjustment via the less-than-precise method of holding a ruler up against the sight while turning the elevation screw. But since I’d done the math beforehand, I had a pretty good idea of how much that sight had to move; I wasn’t just randomly cranking in adjustments and hoping for the best.
There you have it: three shots to get zeroed at 25 yards. Moving back to 100 yards confirmed that I was very, very close. Unfortunately I ran out of time and only had the chance to shoot one, 3-shot group at 100 yards before the range closed. I’ll have to go back another day to fine-tune the zero.
A three-shot zero is pretty good. You can do even better under the right circumstances, though. If you’re shooting a scoped rifle and you have a way to fixture it solidly in place (something like a rifle vise C-clamped to the shooting bench), you can use the one-shot zero trick. Aim at the center of the target and fire one round. Then, with the rifle rigidly clamped in place, adjust your scope so the crosshairs point at the bullet hole. Fire another round to confirm, et voila!
It Didn’t Work! Now What?!?
Using this process, you should be able to get zeroed at 25 yards with no more than 5 or 6 shots fired. Then you can back up to 100 and get your zero fine-tuned with no more than an additional 10 or 15 shots, assuming you’re shooting 3- or 5-shot groups. Basically, if it takes you more than one box of shells to get a good zero, something’s wrong.
First off, check for a loose nut behind the trigger. Have another knowledgeable, experienced shooter fire the gun and see if the problem goes away. If it does, you know where the “problem” lies.
If the gun still isn’t shooting well, look to mechanical problems. You could have a bad or incorrectly-mounted scope, improper bedding, a damaged barrel crown, crappy ammo, or any combination of these (and possibly other) factors. You may need to consult with a good gunsmith to make your rifle happy.
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