This is a question that gets asked a lot on forums for newer shooters and military enthusiasts. When applied to the historical record though not completely accurate; it is more situational dependent than anything else.
Let’s discuss a few factors about this question and when a bolt action rifle should and shouldn’t be used.
What is a sniper?
According to the Oxford Dictionary a Sniper is “a person who shoots from a hiding place, especially accurately and at long range”. Now if you ask a Marine Scout Sniper their definition it would be “A Marine highly trained in field craft and marksmanship, who can deliver long range precision fire on selected targets from a concealed position on selected targets”.
Notice that neither of these definitions specify a type of rifle, or even firearm that must be used.
One of the world’s most deadly and famed snipers didn’t even use an optic.
Simo Hӓyhӓ was credited with hundreds of kills when fighting the soviets in 1939 and 1940. He preferred not to use an optic due to its decreased reliability in extremely cold weather and its increased visual signature. When most people picture a “Sniper Rifle” (a made up term that I compare to the term “Assault rifle”) they assume it has to have an optic.
Even though Simo used a bolt action rifle, the rifle isn’t what made him a sniper. His skill and precision as a shooter are what gave him that title.
Being a sniper has nothing to do with the rifle or equipment used, but a level of proficiency in training and applications of those skills in support of active operations.
Bolt action rifles
Back onto topic. Bolt action rifles comparable to the ones we use today first started to see use in the mid-1800s with the invention of the Gras Rifle. This was the first bolt action rifle that took a metallic cartridge. Metallic cartridges were inherently more accurate than previous loading methods and the bolt action rifle allowed for consistent placement of the cartridge in the breach.
As rifle technology progressed, bolt action rifles quickly became the rifle of choice for precision marksmen due to their increased reliability and accuracy.
Lever action rifles also started to appear around the same time frame. Even though they demonstrated a lot of the same benefits as bolt action rifles, they didn’t catch on to the scale of bolt action rifles.
By the early 1900s every large military in the world was issuing bolt action rifles, so naturally their snipers would take the best shooting ones and make them more accurate.
The Marine Corps For Example would test the 1903 Springfield’s they received from the factory and the best shooting ones were set aside to have scopes mounted to be used by WWII snipers.
Semi Automatic Rifles
Semi automatic rifles first started to make appearances in the end of the 1800s and early 1900s.
There were many prototypes and designs, but most failed to make it to full scale production as they were plagued with reliability issues; then came along John Garand. Although he did not invent the first full production semi automatic rifle, it was the first issued semi automatic service rifle and it used a full size cartridge. It is also one of the most famous rifles of all time, and largely contributed to the US success in World War II, the M1 Garand.
In 1944 the Army switched to the M1C as their standard issue sniper rifle, with the Marine Corps following suit in 1951.
The M1C had many accuracy issues, as the conversion to attach an optic required drilling the hardened receiver.
Shortly after, the army switched to the M1D which attached the optic to a bracket around the barrel.
Unfortunately, even with the increased rate of fire and easier loading, the designers were never able to completely overcome the shortfalls in accuracy when compared to bolt action rifles and both services switched back to bolt action rifles as standard issue for their snipers going into the Vietnam War.
The standard issue rifle for snipers has been a bolt action ever since.
In recent years more rifles have been added to the inventory of your typical sniper platoon or section, giving them semi automatic capabilities if the mission requires it, but the gold standard is still the bolt action rifle.
Advantages of a semi automatic and why they are bad for snipers
There are many undeniable advantages to a semi automatic rifle over their bolt action counterparts; the main one being speed. Having a rifle that removes the step of loading each individual round is absolutely a benefit for the average shooter, whether they are a civilian or a soldier. It allows them to engage more targets in a shorter amount of time with less movement.
This is why no military uses bolt action rifles as standard issue for regular troops. Precision shooting from concealed positions is its own beast, one that requires more careful consideration in rifles used.
The downside of a rifle that does the loading for you, is it has a tendency to cause shooters to rush the rest of their process.
They are no longer waiting on the rifle to be ready to fire, so they rush their position, aiming and trigger manipulation. As soon as you add in stress or fatigue, this issue is amplified.
It is very rare that a sniper would have to engage targets so quickly that a semi automatic would offer a large advantage over a bolt action rifle. The process of manipulating the bolt works as a type of governor on the application of the fundamentals, keeping them more consistent.
If you need proof of this concept just watch someone with a gas gun miss a long range target. They tend to shoot faster. The more they miss, the faster they shoot, instead of slowing down and applying proper marksmanship.
Movement is another advantage for semi automatic rifles. The action works completely internally, minimizing the need for external movement.
The biggest disadvantage for snipers in this is case ejection. Semi automatic rifles have a nasty habit of slinging the brass as far away from the shooter as physically possible. Snipers like to keep their brass from shots to reduce the signature of where their position was and who they were as both of those things could help the enemy establish baselines for sniper activity.
This also requires more movement after the shot, especially if they now have to go brass hunting like a 6GT shooter at a PRS match. There are options that can catch brass, but they add more bulk to the rifle and can sometimes cause stovepipe malfunctions to the rifle, which in turn, requires significantly more movement and time to clear. It also completely takes the gun out of the fight until it is corrected, which in a concealed position could be very problematic.
Disadvantages of a Semi-Auto
Precision
Even with some sevier improvements in the manufacturing of semi automatic rifles in the past few years, most are not capable of the same level of precision as the equivalent cost bolt action setups. There are some exceptions, like the JP Enterprise semi auto line, but in general bolt action rifles are more precise.
Consistency
Most semi automatic rifles have issues with consistency. The more moving parts you have, the less consistent the result will be. With gas system rifles, there is a whole new set of variables that have to be perfect from shot to shot for a consistent result. It is doable, but it is much more finicky than a bolt action system.
Velocity
Semi automatic systems also have a reduced velocity compared to bolt action rifles with the same caliber. Since the gas system steals energy that would otherwise be transferred to the projectile, it leaves the system with a lower overall muzzle velocity. This can cause issues by increasing the curve of the trajectory, increasing wind drift and decreasing the max effective range of the system.
Cartridge
There are some cartridges that have been developed and pushed to mass production that could push a modern semi automatic rifle past the capabilities of the current bolt action rifles in use. The reason these cartridges are not in use by active snipers, is their availability for NATO and their increased cost compared to Military standard ammo that has millions of rounds already in their supply chain.
As a civilian you would have the ability to choose a different cartridge without the same issues that a sniper would run into.
That being said, with all of the things we have discussed, if you found a cartridge that would outperform current military issued rifles, even if it was in a semi automatic rifle, wouldn’t it be even better in a bolt action rifle?