There is an ongoing debate as to whether someone should purchase a semi-automatic rifle or a bolt-action rifle for long-range precision shooting. There are many match grade autoloading rifles - M1a, AR-15 etc that will shoot equal to or as good as a bolt gun.
I will assume “regular rifle” as rifles that are not precision rifles.
I see alot of other answers about the skills of the shooter, that has some part to play but it is not entirely true. Theoretically it should work out that way, but in the real world it just doesn't.
Unstable positions compound the issue. All the comments made on this subject are well-considered and, by and large, correct. It depends on the individual rifle, and there are so many factors that make an accurate rifle that it would take three pages to list. That's why tighter groups (the gun sending the bullet to the same place) means the gun is more accurate. IMHO, bolt actions are inherently the most accurate form of rifle action for several reasons; if the action is a single shot the cross section of metal in the action is larger and therefore resists the torquing action imparted from the rifled barrel better than other designs. Here are a few reasons to pass on that next semi-auto. The two firearms fill to vastly different roles. In it, you will find a mix of different bolt actions that are applicable to many different shooting scenarios. Bolt rifle barrels can be totally isolated allowing free and predictable harmonics. Today, it's not a given that every gun owner has at least one bolt gun in their safe. Is a bolt action any more accurate than a semi auto? The mechanics of a bolt-action rifle are not all that complex. At top is a Miller Classic rifle, to my knowledge the most precisely built bolt-action rifle made today. Some tout the esoteric notion of the "inherent accuracy" of a cartridge. What about at 100 yards? Let’s explore which fixes can be done at home, and which will require the services of a good gunsmith. But for the sake of argument, a modern bolt action rifle will be more accurate than an AR. Bolt action rifles aren't necessarily more accurate. Bolt-action vs. Semi-auto. Many bolt actions have more accuracy though and for serious target shooting a heavy barrel bolt action is the best. Yet, the simplicity and strength leads us to expect the finest accuracy from the design.
Bolt action rifles do not requrire this - and make for the cartridge to be more uniform. It's more a matter of the comparison of apples and oranges. As you might guess, there is no one component that makes a rifle intrinsically accurate. Among the myriad of forms of repeating rifles, the bolt-action is among the simplest.
Almost all semi auto rifle deigns need a gas system, and that requires attaching things to the barrel that vibrate differently than the barrel, making the harmonics difficult to predict. While they are not all wrong, they are all a long way from being entirely correct. Bolt action rifles aren't necessarily more accurate. The American rifle has become a standard among budget guns; it is an affordable, accurate rifle family that has grown to include eight different models. There is an ongoing debate as to whether someone should purchase a semi-automatic rifle or a bolt-action rifle for long-range precision shooting. Autoloaders also tend to go through ammo like water - and - the barrels will wear out. ARs are able to produce some pretty dang good accuracy but a bolt gun, for the most part, will be more accurate. This is why most precision rifle competitors start with bolt-action rifles—they are just plain easier to shoot well.
Bolt-action vs. Semi-auto. Two very accurate hunting rifles from the shop of the David Miller Company in Tucson, Arizona. I will assume “regular rifle” as rifles that are not precision rifles. 4 Reasons You Need A Bolt Action Rifle. Also shown (above) from the Miller shop is the Marksman rifle. More uniform will be more accurate. Theoretically it should work out that way, but in the real world it just doesn't.
This is an article about the best bolt action rifle options. Therefore, bolt actions tend to be more accurate.