Hornady Concentricity Gauge - Caliper

Hornady Concentricity Gauge

In Review by Rich2 Comments

If you are into shooting at all, you are either reloading already, or you probably will begin to in the future. Particularly in the precision shooting realm, affordable and match grade are terms that do not mesh well. At the time this review was written, Federal Gold Medal Match ammunition, is going for $29.99 per box of 20 rounds. That works out to $1.50 every time you pull the trigger. That’s all fine and well and you can’t take anything away from Federal, they make great ammo. Unfortunately, most of us can’t afford to shoot as often as we want at that price point. So we learn to reload our own ammo. Reloaders are a fickle and superstitious group, always looking for ways to make their ammo a little better, a little more accurate, and a little more consistent. Runout is one issue that can cause issues for the reloader, and Hornady has a solution, the Hornady Concentricity Gauge.

What is runout? Essentially, it’s a lack of consistency in the angles of a loaded cartridge. If you were to draw a line straight down the middle of the case and call that your centerline, the ideally loaded round would have the middle of the base of the bullet, and the tip of the bullet, both lining up on that centerline. Variations in neck thickness, cases with necks that aren’t concentric, play or slop in your reloading press, and a long list of other factors can contribute to a lack of concentricity. With a round that has runout, or a lack of concentricity, you have the bullet pointing a few degrees off of the centerline. How much this little bit of variation really matters to accuracy downrange is the topic of much debate and controversy.

So much so that here at AccuracyTech, we plan to test it and find out. We are going to cherry pick some loaded rounds showing .005 or more of runout and fire a few groups with them to see what kind of effect that has on accuracy. We will then compare it to rounds we have checked and either show runout of .001 or that show more but had the runout corrected using the Hornady Concentricity Gauge.

Why does runout matter? Well, the theory is this, all these little sources of inaccuracy can combine to cause issues with accuracy. With the projectile not concentric with the case and the chamber it creates pressure and tension on the case, yielding inconsistent release of the projectile. This can then lead to inconsistent barrel timing with varying muzzle velocities and less consistency downrange. We plan to test it and see, but in the case of the Hornady Concentricity Gauge, it performs as advertised. It provides a means of measuring and correcting the runout found on hand loaded ammunition.


The main body of the Hornady Concentricity Gauge is cast iron, making for a solid base. There is a shell holder that you can place the base of a loaded round into and there is a hollowed out extension on the other end for the tip of the projectile to rest inside. You can then adjust where the dial caliper meets anything in between. This is especially useful because you can use it to check concentricity of a loaded round, or even a case neck and body. There is a simply pull and pivot lever that tightens or loosens the dial caliper and allows it to float forward and rearward along the rail beneath the shell holder.

Hornady Concentricity Gauge - Front

Hornady Concentricity Gauge – Front


Hornady recommends you line the dial caliper up on a specific portion of the projectile for measurement. You then spin the cartridge after zeroing the dial caliper and the gauge will identify any runout present in the cartridge. When you have identified where the bullet is farthest from concentric, there is a small screw with a rubber head that you can dial in to ‘push’ the projectile back towards concentric. It takes some fiddling to work up a system for correcting the runout but once you get the hang of it, the process is quite easy and fairly efficient time wise. You can then correct any runout present in your cartridges with the Hornady Concentricity Gauge so that, ideally, you have very concentric rounds being chambered. I’ve even gone as far as to chamber a few after correcting them (with the firing pin removed from the bolt, of course) to see if merely chambering the rounds was enough to induce runout and perhaps negate the time spent on the process in the first place. I’m happy to say that after trying this several times, I noticed no increase in runout after chambering the round several times from what it was going into the magazine.

Hornady Concentricity Gauge - Upper View

Hornady Concentricity Gauge – Upper View

Hornady Concentricity Gauge - View Of Dial

Hornady Concentricity Gauge – View Of Dial



The heavy use and high contact areas of the tool are made of appropriate materials, cast iron and aluminum. Durability isn’t a huge issue for a bench tool because we won’t be taking it into the field or to the range and knocking it around. However, nobody likes paying for tools that break or don’t last. That said I don’t see much potential for the Hornady Concentricity Gauge to break or fail unless it is abused in some manner as to cause a failure.


The price on the Hornady Concentricity Gauge puts it right in line with other special purpose tools for the reloading bench. It isn’t a steal of a bargain nor is it anything that would break the bank. Whether or not it is a tool you need to bother with in the first place remains the subject of much discussion and disagreement. Keep checking back to read up on our test of concentric versus non-concentric ammo fired for accuracy.

Owner and Proprietor of AccuracyTech, LLC. Rich is a Firearms Enthusiast, Precision Rifle Competitor, and Writer. He is committed to bringing readers quality reviews and articles related to the Precision Shooting Sports. If you have any questions for him, please use the contact form on the site.


  1. I had a new never fired bushmaster A.R. 15 with a fluted competition barrel that was chrome lined. Was using a viper 6 to 24 power with with a 50 mm objective lens.
    Temperature was 85 to 90° according to my weather station sensor that I had mounted on my barrel next to the receiver.
    I let the gun acclimate to the existing temperature before shooting.
    The Bore of the barrel was polished to remove tooling marks, then a rag saturated with 60% Molly grease was run up and down through the boar 60 times to make sure the complete bore was covered with grease being careful not to get any of the grease inside the chamber, then all grease was wiped out of the bore until the rag came out clean.
    I was shooting 55 grain bullets using Winchester brass.
    The bullets were moly coated in a case tumbler with ceramic media polishing the moly into the copper.
    I let the first round fly then watched the temperature of the barrel increase. Then did not shoot again until the temperature of the borough was equal to the outside ambient temperature.
    The first round was close to the bull’s-eye but all subsequent rounds were walking to the left and high about 2 inches to the left and 3 inches high at about 11 o’clock.it’s the last seven shots were inside a $.25 piece.
    Each round was fired when the barrel cool down to the ambient temperature.
    The last seven shots I fired were in The 11 o’clock position from the bull’s-eye.
    All shots were taken from 100 yard range.
    I said all that to say this. Will I always need to fire a few rounds until the barrel settles down?
    I was only reloading with RCBS reloading press and dies and other such equipment. No tricks used for competition reloading.
    So is this about the best I can expect from my reloading equipment?
    Will the barrel always want to shoot low and to the right on the first few fowling rounds after the elevation and windage is adjusted so the bullets land in the bull’s-eye?
    I had the bullets seated not very deep in the neck trying to find the lead for the lands. I could not find the lead.
    Had to feed the bullet one at a time into the chamber because they would not fit in the magazine.
    I ejected a live around and the bullet stuck in the boar. Inertia threw the bullet into the boar.
    Is this good accuracy for that type of rifle or would competition reloading increase the accuracy?or do I need a better barrel for greater accuracy?I don’t think they use semi automatics in F class shooting do they?

    1. Author

      Yes, you will experience a shift in point of impact from a barrel that is cleaned out, to one that has been fouled. How much the shift is depends on how clean the barrel is but it should be fairly consistent. So if for example, as you said, you saw a 2 inch left and 3 inch high shift at 100 yards, you will likely always see a shift of roughly the same magnitude from clean bore to fouled. You don’t really need to clean the barrel so vigorously. When you do, you shouldn’t have to clean it again for several hundred rounds. I clean mine about every 300-500 rounds for shits and giggles. I’ve yet to fire so many rounds through the barrel without cleaning that it gets dirty enough to affect the accuracy of the barrel.

      I doubt any of this has to do with runout of your loaded rounds. 7 shots inside a quarter size hole is more than adequate for competition in a tactical/practical rifle match. I also doubt inertia threw the bullet into the bore, I think you had them loaded so long that the tip stuck in the lands and you pulled the case off of it. Look into bullets that aren’t a VLD type projectile and seating depth matters a lot less. I’m stunned at how well the Berger Hybrids shoot regardless of seating depth! Sorry for the slow reply!

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