Sniper’s Choice: Bolt vs. Semi-auto Precision Rifles

• Recoil
• Gas release
• Moving components

Recoil

The bolt-action rifle, when fired, has only one stage of recoil, this being recoil to the rear—into the shooter’s shoulder pocket. The semi-auto precision rifle, when fired, has three stages of recoil: One being to the rear as the bullet exits the muzzle, another to the rear as the bolt slams into the buffer, and the final stage as the bolt slams forward, picking up an additional cartridge. Because the bolt-action rifle has only a single stage of recoil to the rear, some shooters find they can “drive the rifle” in a superior manner to semi-automatic rifles.

Gas release

When a cartridge is fired inside the chamber of a bolt-action rifle, the force from the burning charge and expanding gases propels the bullet down the barrel. However, some of the energy is transferred to the shooter through its normal recoil. In a semi-automatic rifle, some of the energy used to propel the bullet down the barrel is used to cycle the action.

Moving components 

The moving components of the two rifle platforms must also be considered. Typically, precision-rifle shooters prefer the bolt rifle simply due to its lack of moving components, and by extension, simplicity and reliability. Taking a look at the bolt rifle, the only moving part is the bolt, which is manually operated by the shooter. Once the bolt is locked, the entire rifle is merely one solid component, thus making it easier to control through recoil and avoiding bullet-impact deviation downrange due to shooter-induced movement.

The semi-automatic precision rifle will always have a moving part in some section of the rifle, this usually being in the upper and lower receiver. If you’ve ever looked through the scope while in the prone position, you may have noticed that the slightest movement with your firing or support hand causes the upper receiver to shift slightly left or right, or in some cases, up or down. This slight shift/movement within the scope may be caused by a number of factors: shooter flinch, undue sympathetic squeeze as the rifle is firing, etc.

As the shooter begins to fire or begins to perceive recoil, the shooter may cause the upper and lower receiver to shift where the two components meet, thus causing a change in desired point of impact when the rifle is fired. To the untrained or novice shooter, this may seem like a “sloppy gun,” or a rifle that is unable to achieve 1MOA.

Malfunctions

Semi automatic

As with any semi-automatic rifle or handgun, we can find an array of weapon-induced or shooter-induced malfunctions. Some of the malfunctions I have commonly seen within the semi-automatic family of precision rifles include the following:

• Stovepipe: A stovepipe occurs when the casing that has been ejected is caught in the ejection port by the slide. This could be due to unburned powder, obstructions of various sorts that are placed near the ejection port not allowing the complete ejection of the spent casing, and poor-quality ammo.
• Failure to extract: This results when the cartridge case remains in the chamber of the rifle. While the bolt and bolt carrier could move rearward only a short distance, more commonly the bolt and bolt carrier recoil fully to the rear, leaving the cartridge case in the chamber. A live round is then forced into the base of the cartridge case as the bolt returns in the next feed cycle. This malfunction is also one of the hardest to clear. A failure to extract could be caused by short-recoil cycles brought on by a fouled or corroded rifle chamber. A damaged extractor or a weak or broken extractor spring can also cause this malfunction.
• Failure to eject: Here, a malfunction occurs when the cartridge is not ejected through the ejection port and either remains partly in the chamber or becomes jammed in the upper receiver as the bolt closes. This could be a result of carbon or fouling on the ejector spring or extractor, or from short recoil. Short recoil is usually due to a buildup of fouling in the carrier mechanism or gas tube. Resistance caused by a carbon-coated or corroded chamber can impede the extraction, and the subsequent ejection, of a cartridge.

• Double feed: This malfunction occurs when a round is in the chamber and a second round attempts to feed into the chamber. This results in a true jam. On most semi-automatic weapons, the slide has a limited motion and the magazine will not eject by pressing the magazine release.
• Failure to feed, chamber, or lock: A malfunction can occur when loading the rifle or during the cycle of operation. Once the magazine has been loaded into the rifle, the forward movement of the bolt carrier group could lack enough force (generated by the expansion of the action spring) to feed, chamber, or lock the bolt.  Some of the causes could be the result of the following:

1. Excess accumulation of dirt or fouling in and around the bolt and bolt carrier.

2. Defective magazine (dented, bulged, or a weak magazine spring).

3. Improperly loaded magazine.

4. Defective round (projectile forced back into the cartridge case, which could result in a stubbed round or the base of the previous cartridge could be separated, leaving the remainder in the chamber).

5. Damaged or broken action spring.

6. Exterior accumulation of dirt in the lower-receiver extension.

7. Fouled gas tube resulting in short recoil.

8. A magazine resting on the ground or pushed forward could cause an improper lock.

• Failure to fire: This malfunction occurs when a cartridge fails to fire despite being chambered, the trigger pulled, and the sear releasing the hammer. This occurs when the firing pin fails to strike the primer with enough force, or when the ammunition is defective. Probable causes of this malfunction include excessive carbon buildup on the firing pin, thus restricting the full forward travel of the pin, or a defective or worn firing pin. Proper inspection of the ammunition could reveal a shallow indentation or no mark on the primer, indicating a firing-pin malfunction. Cartridges that show an indentation on the primer but did not fire may indicate faulty ammunition.

Bolt action

One major benefit of having a bolt-action rifle is the lack of malfunctions they produce. Here are a some of the most common bolt-action malfunctions that I have seen over time, both shooter induced and weapon induced.

• Falling firing pin: A falling firing pin occurs when the shooter closes the bolt too fast or too hard. The firing pin will not stay in the rear position, but will instead “fall forward” and move into the fired position. When this occurs, the shooter is not able to fire the rifle. The most common causes are a lack of maintenance on the bolt, dirt or buildup on the bolt face, etc.

• Failure to fire: Failure to fire in a bolt gun occurs in the same manner as in the semi-automatic.

• Failure to feed: A failure to feed occurs in the same manner as the semi-automatic. The problem usually occurs when the shooter bolt overrides the cartridge in the internal or external magazine.

Performance in the field

Although one rifle platform may surpass the other in certain applications or instances, we must also understand that a given platform is only a tool for a certain task, and may not be applicable in every situation. Let’s take a look at each platform’s advantages and disadvantages by discussing different situations/environments.

Multiple engagements

Precision shooters may find themselves in a multiple-target engagement situation not only in combat (defensive or offensive), but in a timed competitive event as well. As we all know, holdovers and holdunders will greatly increase our speed at getting rounds on target, but when time matters the most, the semi-automatic rifle will by far surpass the bolt rifle. The amount of time it takes to run the bolt, acquire the target, and get a proper trigger squeeze on target is greater than that of the semi, as the shooter only has to transition through targets and apply a proper trigger squeeze while utilizing the trigger reset.

Use in urban and woodland environments

In regards to the use of a precision rifle in an urban environment, speed, accuracy, and possible presentation of multiple targets plays a big role in the choosing the superior platform. While the bolt rifle may have the greater advantage in accuracy, which is commonly needed when engaging partially obscured targets at various ranges, it may lack the speed needed to engage multiple targets.

The semi-automatic rifle, while being superior in speed and engaging multiple targets, may lack the accuracy needed to engage small, partially obscured targets. This is usually due to the shooter not properly driving the rifle while in various alternate shooting positions, but it’s a consideration, notwithstanding.

Aerial platforms

As difficult in nature as aerial shooting can be, the amount of rounds used to engage a target while the shooter is airborne are typically more than three, due to the lack of a stable platform, the amount of time the shooter is actually on or able to engage the target, and proper lead needed to engage the target. This being the case, the semi-automatic rifle surpasses the bolt-action.

by Nick Irving

This post first appeared on loadoutroom.com