In the world of rifles chambered for the .50 BMG cartridge there has only been one semiautomatic that has been truly successful: the Barrett Model 82 series, also known in the U. S. military as the M107. While it is fairly easy to design a bolt-action around this cartridge, it is far more difficult to design a semiautomatic .50 BMG, particularly with the accuracy, reliability and durability of the Barrett. What many end users do not realize are the huge tactical advantages a semiautomatic .50 has over a bolt-action .50.
The most fundamental advantage is that the sniper, with a semiautomatic, can fire a shot and keep his eye on the target through his scope. If a second shot is needed it can be taken immediately. With a bolt-action, the sniper takes his shot then does one of two things. One option is that he cycles his bolt to chamber a new round while at the same time moving his face out of the way of the bolt and losing sight of the target. The other is that he keeps his eye on the target to see the results of the first shot, then cycles the bolt and loses sight of the target. Either way the bolt-shooter cannot make an immediate follow up shot with or without the feedback of any needed sight correction.
While the “one shot one kill” mantra sounds good, in real life it is more often than not the second or subsequent shot that does the damage. When working at extreme distances there are so many variables involved that affect the flight of the bullet that the second round fired, with aiming changes made possible from feedback from the first shot, is typically the most effective. This also applies to the third, fourth and all subsequent shots delivered to the target. No .50 bolt gun can even dream about being as effective as possible in such a situation.
There is another tactical technique that the semiautomatic Barrett can take advantage of that no bolt gun can match. It is called “traversing fire defeating cover.” This technique first came to my attention during the Vietnam War when it was employed by a SSG named Crow in the 1st Cavalry Division Sniper Detachment. In his case he was using an XM21 (M14 based) 7.62mm semiautomatic sniper rifle and the cover involved was generally trees. In an engagement between a 1st Cavalry Division Infantry unit and an NVA force he would crawl forward to the point of contact. He would then identify
likely enemy firing positions usually behind a tree or other cover or concealment. Starting at one side of the suspected position, aiming about a foot off the ground, he would shoot a round, move his aim over six inches or so, and fire the next shot continuing this pattern across the suspected position in quite a rapid-fire sequence. A high percentage of the time he would eventually hit the enemy soldier behind the tree or other cover/concealment. In one particular engagement Crow was credited with nine kills using this technique. Some sniper “authorities” have tried to claim that this technique is not sniping since it uses precision rifle fire to kill enemy soldiers that would otherwise be safe. Who cares? It works!
This same technique has been used successfully with the Barrett Model 82A1 or M107. The first such application I am aware of was in Desert Storm by a Navy SEAL shooting a Barrett. In this case, the bad guys were behind a brick wall. The SEAL sniper engaged the wall about a foot off of the ground and rapidly traversed the wall with well spaced shots, each of which blew through the wall. Eventually his fire took out the bad guys before they could displace to a safer position. This technique has proven to be extremely effective against enemy sniper or crew-served weapons positions on rooftops and in windows in Iraq. Again, bolt-action .50s can’t hope to achieve the same effectiveness because of their inability to make such rapid precision fire.
Yet another tactical technique available to the sniper that cannot be achieved with a bolt-gun is called bracket shooting. The sniper has a valuable target at extreme range, be it materiel or human. Using his rangefinder, ballistic calculator, etc., he sets up to take the shot. However, instead of taking just one shot, he takes at least three as fast as he can fire, changing his aiming point between shots.
Some snipers like to fire their first shot where their best estimate is and then bracket that shot with the next two shots, firing a couple of feet to the right and left of the first shot. Others prefer to bracket the target with traversing fire right-to-left or left-to-right. Either way it is entirely possible to have three bullets in the air before the first one arrives when firing a semiautomatic Barrett.
Obviously the size of the bracket interval depends on the size of the target since the .50’s are primarily anti-materiel sniper rifles. Regardless, the hit probability goes up exponentially over that of just one shot even if the one shot is fired from a somewhat more-accurate bolt-action rifle.
One of the primary military targets for the Barrett M107 semiautomatic is soft-skinned vehicles. By their very nature they often present themselves as moving targets. Using the M107, the shooter leads the target the amount he thinks will do the job and makes the shot, continuing to track the target in his scope sight. If the first round does not hit the target, the spotter will call out the change of lead needed. Depending on the distance and size of the target, the change in lead can be in feet, meters, or mils. If the spotter calls out “plus two,” the shooter adds two units of lead and fires the next shot while the spotter makes additional lead calls until the target is neutralized.
Trying to use this technique with a bolt- action is generally not possible because the shooter cannot chamber the next round and continue to track the target in his scope at the same time.
It is the nature of materiel targets that they often take more than one solid hit to achieve the desired results. The rapid-fire capability available from a Barrett M107 allows the shooter the chance to fire several shots to achieve the mission of neutralizing the target and still do it quickly enough that the sniper can displace before the enemy comes back with counter fire. The poor sniper with a bolt-action has to either risk not neutralizing the target or risk receiving counter fire by continuing to shoot slowly.
Yet another advantage of the semiautomatic Barrett system over the typical bolt action .50 is that there is noticeably lower recoil with the former. Everything else being equal, the semiautomatic action seems to spread out the recoil and make it much less punishing. This makes for a more alert and effective shooter who is much less likely to flinch or lose concentration when making a shot. This leads to better shooting and more effective sniping.
The sole significant advantage of a good bolt-action .50 sniper rifle over a good semiautomatic .50 sniper rifle like the Barrett M107 is that it can be somewhat more accurate, particularly with match grade ammunition. However, by using the techniques outlined above, the Barrett M107 will still get more kills in the long run even though more shots are fired to do it. Using machine-gun grade ammunition, the typical bolt action .50 will have little if any accuracy advantage over the semiautomatic Barrett.
There is no question in my mind that for the mission of counter materiel sniping, the reliable semiautomatic feature of the Barrett M107 makes it without peer in the field of .50 sniper rifles.