What Influences Handgun Accuracy?

Shooting accurately

What parts of a gun actually contribute to handgun accuracy or accuracy of any gun for that matter? Clearly, there are certain things that make a gun accurate, but what are they?

There are a few different factors, some of which are the gun and some are the ammunition.

Granted, most of what will compromise accuracy is actually the shooter. Far, far more of what will put a bullet where you didn't want it to go is you instead of the gun; your sighting, your trigger pull and so on have far more to do with it. However, there are a few design elements and so on that do influence how accurate a pistol or other type of firearm will be.

The Gun Barrel

First on the list of what impacts what makes a gun accurate is the barrel.

Now, a barrel impacts accuracy in several respects. Most obvious is that the rifling in the barrel spins the bullet. Since the barrel is also the part of the gun that touches the bullet in flight, it also sends it on its way.

Rifled vs Smooth Bore

Next is the metallurgy and construction of the barrel itself. Since a gun barrel is subjected to a certain amount of stress due to the bullet being fired, how it handles that stress plays a part as well.

When a bullet is fired, the barrel vibrates. This can cause minute plastic deformations (where the metal stretches) which, over time, compound into large enough deformations to impact accuracy. Most barrels have a pre-defined service life, but this can be accelerated with poor construction. Additionally, the stiffness of the metal correlates how much the barrel vibrates; the more a barrel vibrates when shot, the less consistent trajectories will be.

The bore - the inside of the barrel, which a bullet travels down - should have a uniform twist rate which slightly increases at the end of the barrel. Twist rate is how many inches of barrel it would take for the spiral grooves in the bore to make one full revolution. A 7:1 twist rate means 7 inches of barrel per full revolution of grooves.

Also, the bullet itself matters as twist rates are best suited to certain grain weights. As a general rule, bullet flight tends to be the most stable with a slow twist rate (meaning a long distance between twists, say 24 inches) though this is affected by caliber, as each tends to have its own optimal twist rate. A Glock 19, for instance, has a twist length of 9.8 inches as 9mm rounds tend to be quite accurate with a twist length of 9 to 11 inches; a Colt Series 70 has about a twist length of about 16 inches for .45 ACP.

Handgun Sights

Dialing in your handgun sights is important

Another critical factor in accuracy is the sights. Granted, how you use them matters as much, if not more.

That said, if you place a gun in a bench rest with the sights perfectly aligned at the center of a bullseye, you should hit the center every time. If it doesn't, that means the sights aren't aiming well.

That said, the fix is almost always relatively obvious. If shots are landing too high or too low, you change the elevation; if too far to the left or right, then it's the windage.

How you're using them, though...is another matter.

Clearances And Accuracy Vs Precision

Proper clearances and tolerances are important - they are not the same!

Clearances in and around the barrel also matter.

A gun, you see, is a mechanical system that creates an explosion. That explosion creates a fantastic amount of pressure, which sends a projectile (ie the bullet) out of a tube. How to ensure that it works consistently well? Make sure that pressure isn't being lost anywhere.

When a bullet is inserted into the chamber of a gun, it forms a seal of sorts. Perhaps not perfectly airtight, but a seal nevertheless. How to ensure it works as well as it should? Make sure the clearances between those parts are as tight as possible.

Clearances in the chamber and the barrel are both critical, as are the tolerances between the slide and frame in semi-autos. The tighter the barrel and other parts are held in place, the less they can move. This is why accurized rifle barrels are often floating rather than bedded; if the stock deforms at all, it can actually bend the barrel.

In revolvers, by contrast, the gap between the end of the cylinder and the forcing cone (at the throat of the barrel) should be as small as possible to ensure a proper seal.

These tighter clearances also contribute to precision as well as accuracy, which aren't actually the same thing.

Accuracy is placing a bullet exactly where you want it to go; precision is doing so repeatedly. Plenty of guns are accurate, but the details - and the shooter - determine whether they are precise as well.

Don't be too quick to judge your brand new firearm either, most pistols go through a break-in period.

Ammunition Also Plays A Major Role

ammunition plays a role in accurately shooting your firearm

There are other factors that impede handgun accuracy as well, another critical component being ammunition.

The aerodynamics involved in bullet flight really only affect velocity and drop rather than accuracy; an accurate bullet with a dramatic drop - say, a .45-70 round, which tends to drop dramatically after a couple hundred yards - can be placed accurately and precisely by a shooter that understands the drop at the appropriate distance.

Instead, what matters is propellant and - again - clearances in bullet construction. As to clearances, the crimp and fitment of the bullet inside the case determine the seal of same. A proper seal puts as much pressure generated by the combustion and resultant gas expansion behind the bullet as possible, guaranteeing sufficient velocity and a truer flight. Similarly, quality powders burn at constant rates and do so consistent, with little if any variation between lots of cartridges.

Therefore, a bullet of good construction with a quality powder will be more accurate than one with merely adequate construction and decent powder.

Ever group carry ammo tighter than your practice ammo?

Granted, much of accuracy and also precision also come down to shooting technique. The trigger pull and sighting technique are hugely important, arguably more so than anything else. However, in mechanical terms, these are the important aspects contributing to accuracy.

Now that's an accurate post on gun accuracy
Sam Hoober  

About The Author

Born in southeastern Washington State, Sam Hoober graduated in 2011 from Eastern Washington University. He resides in the great Inland Northwest, with his wife and child. His varied interests and hobbies include camping, fishing, hunting, and spending time at the gun range as often as possible.

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