“Mechanical accuracy” can be loosely defined as the precision of fire a firearm is capable of, and a lot of people will pay a lot of money to get it.
Custom and semi-custom 1911 and 2011 pistols are the trendy handgun du jour (it used to be custom Glocks) along with “Gucci” ARs with shooters pursuing 1 MOA or better, to say nothing of the bolt-action space, which gets frankly insane.
It has never been the case that you should be satisfied with a less-accurate weapon, but it’s also that most people don’t consider what their practical needs from equipment really are.
What Creates Mechanical Accuracy?
Mechanical accuracy is a balance of multiple factors, culminating in a smaller group on paper.
First, you have lock-up: how tightly the breech or bolt locks up with the barrel. Off-gassing affects the burn, which affects trajectory.
Then you have the barrel. Metallurgy, twist rate, and profile can all impact accuracy both across the board and with specific ammunition. Manufacturing can as well; proper stress relief and heat treatment ensures groups don’t open up or point of impact shifts dramatically as the barrel heats up.
Then you have barrel harmonics. Does the barrel resonate freely, or does anything impinge on like a handguard, stock, or other part of the gun? That’s why AR-platform rifles are generally held to be “more accurate” with a free-floating handguard and why accurizing bolt-action rifles has long included free-floating the barrel and bedding the action (pillar and fiberglass bedding) so that it’s as rigidly set into the stock as possible.
And that’s not even touching on the ammunition used, which can have even further effects. The brand and type of powder used, bullet weight, bullet shape…a lot of different things have an effect.
Firearms that are optimized for accuracy (accurized) usually require a lot more work in their construction, adding significantly to their cost. Your standard Springfield 1911 is not nearly as accurate as an STI or Les Baer, or for that matter, a fully custom build like a Joe Chambers gun.
The point is that a lot goes into the mechanical accuracy of a gun.
How Much Mechanical Accuracy Matters In The Real World
A lot of people spend a lot of money every year on upgraded barrels. It’s one of the most highly recommended upgrades for Glock pistols, which have been lamented for being somehow “less accurate” for decades.
People will spend a lot of money on a supposedly higher-tier AR-15 to get a more accurate rifle.
How much do you need it? Well, consider something for a moment.
Typical service rifles in the US armed forces since the late 1800s have typically been capable of 2 to 4 minutes of angle, including the modern M4 platform. Typical AK-47 rifles are held to be capable of about 3 to 4 MOA.
Gewehr 98k rifles the Germans selected for snipers or designated marksmen around World War II rarely shot better than 2 MOA. 1 MOA sniper rifles in the US armed forces weren’t common until the Vietnamese war, usually Remington 700 and Winchester Model 70 rifles fitted with match barrels with pillar and glass-bedded stocks.
In other words, most service rifles used by professionals in wars are rarely (except for modern sniper rifles) capable of 1 MOA groups. If people who get in gunfights for a living are able to survive with 2 MOA+ rifles, how accurate does a home defense carbine need to be?
It’s said that Glock pistols are rarely capable of better than 2 inches at 25 yards on a bullseye, but how many people can hold a 2-inch group at 25 yards regardless of what type of pistol, let alone a Glock?
The top tier of 1911 and 2011 pistols are said to hold as tight as a 1-inch group at 50 yards, but the same idea applies. Outside of the top tier of bullseye shooters and a handful of others who don’t shoot bullseye, how many people are actually capable of that without using a rest?
You might not know this, but right now is the golden age of hunting rifles. You can buy a Ruger American or Savage Axis (among others) off the gunstore shelf for $500 or less, and it will shoot 1 MOA groups in most calibers with a lot of ammunition.
Given that most Americans who hunt rarely have shot opportunities beyond 200 yards and are barely capable of a 2 MOA group off-hand…it matters less than the marketing materials would suggest.
Unless it does, actual sniper rifles for actual snipers do need to be that accurate. Bullseye shooters who are trying to be competitive do need that capability. Hunters who regularly have shot opportunities at 300 and 400 yards actually can need a 1 MOA gun to fill their freezers successfully.
So, what actually makes a gun accurate? The shooter does. Invest in yourself and invest in improving yourself before worrying about whether or not you have a match barrel or whatever.