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Understanding and Preventing Scope Bite

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In early 1776 in Philadelphia, PA, the American portrait painter and patriot, Charles Wilson Peale visited David Rittenhouse, the American astronomer and head of an observatory. Peale was also known for making telescopes, clocks, and surveying instruments. A gunsmith had helped Peale assemble a gun with a telescopic sight that Rittenhouse had made on Peale’s behalf. Peale kept a daily journal in which he recounted the events of his days, and there were several entries relating to the development of his special firearms project. A few weeks later, after he took possession of the gun and tried to reset it, his diary read: “Mfixing piece with springs to prevent the eye from being injured by the kick of the gun.” One of the first men in history to shoot with a rifle scope soon suffered from scope bite.

Scope bite is a pernicious and sometimes painful (not to say embarrassing) phenomenon that can happen to shooters using a shoulder stock firearm. Scope bite can be caused by improperly mounted optics, poor cheek welding, improper eye relief, or a combination of some or all of these factors. The rearward recoil motion of a firearm and the hard outer edge of a riflescope can cause injury, scarring, and discomfort by violently coming into contact with the shooter’s eye socket or orbital/lower frontal area due to the mispositioning of his face and head relative to his optics.

Scope Bite starts with your rifle and optics

In order to avoid scope bite, a shooter must have some spatial awareness and a type of harmony with their firearm. This is achieved by an understanding of the relationship between the rifle and its scope and their bodies, particularly from the position where the rifle is to be fired. A good shooter will understand where his shoulder and face are in relation to the rear ocular lens of the optic so that whenever the stock is brought up to his shoulder and he brings his scope up to eye level, the eye will see a clear vision picture with a scope that will never “cut” them, no matter how strong the firearm’s recoil. Practicing this involves positional dry-firing and rehearsal so that every aspect of the firing position is isolated and refined, which is why sniper or competition rifles come with hyper-adjustable stocks. After practicing positional dry-firing with his firearm, shooters will have an idea of ​​where everything is supposed to belong and what will feel good.

Outside of specialized long eye relief scopes or handguns, most rifle scopes require about 3 to 4 inches of space between the shooter’s eye and the scope’s ocular lens for proper eye relief and a sharp sight picture. An eye too far or too close to the ocular lens will perceive dark shadowed crescents at the periphery of the sight picture, or even a dark, hazy ring around the sight picture. This phenomenon is known as drop shadow. Shooters can easily and positively determine if their eye relief is correct: their sight picture will always be clear. The eye relief is either decent, meaning the sight picture is perfectly clear, or it’s not. It’s as simple as that.

This graphic (courtesy of LuckyGunner.com) illustrates what good eye relief looks like in addition to visual clues that the eye relief is not correct.

Regardless of a gun’s design or style, there is only a limited amount of real estate available above its receiver where installing a mount or rings makes sense. A scope that sits too far back or too close to far in front can not only interfere with its own operation, such as the need to dial turrets or turn the focus/parallax adjustment and can also interfere with the operation of the firearm itself. Improper mounting can also result in the scope itself clashing with external surfaces or firearm-mounted accessories, such as a lens bell colliding with a rear sight assembly. And finally, if an optic is not mounted on that particular “sweet spot” that avoids interfering in the manner described above, the shooter may not get his proper eye relief no matter how hard he tries to to correct. On the other hand, an improperly mounted scope might have acceptable eye relief but have a risk of the shooter still getting bitten. This is why the way a shooter mounts the butt of a firearm on their shoulder and aligns the scope with their eye is so crucial.

Knowing how to configure a stock is essential

The U.S. Army Marksmanship Manual for Rifles and Carbines (TC 3-22.9) states that there are two truths in marksmanship: To properly engage a target, a rifle must have the correct alignment and sight picture, and that the rifle should be fired without disturbing its aim. A shooter who properly mounts their stock to their face and shoulder (essentially having a solid cheek weld) will thus be able to get a clear sight picture. A good cheek weld comes from two things, A) the butt of a firearm fits the shooter properly so that B) the shooter can put their face in the correct place on the butt for a good sight picture.

An ill-fitting stock will impair good marksmanship in several ways:

  • An ill-fitting stock can put a shooter out of order by making it difficult to align the sight with the scope or sights.
  • It could also unintentionally set up the shooter to be “bitten” by its scope.
  • This can amplify the perception of recoil in the shooter’s shoulder pocket and/or face along the comb of the butt, making the shot more painful than necessary, which can also develop a thrill of anticipation and lead to a loss of precision.

The same way a shooter should be able to visually identify what good eye relief looks like. A shooter must understand the concept of Length of Draw (LOP) and how it applies to him personally. Pull length is the distance (usually measured in inches) from the trigger to the rearmost vertical edge of a stock. The concept behind LOP is actually one of the most universal details of a good shot, regardless of shooting discipline. You can’t and won’t shoot well if their stock is too long and doesn’t fit well. Being aware of this concept is crucial to avoiding range sting. The stock edit is the keystone to all the other details that result in a good, consistent edit.

A good mount and cheek weld is one that will allow the shooter’s face to have a clear sight image while maintaining a safe distance from the rear end of a recoil scope. This won’t happen without a well-adjusted stock and a decent LOP. Different shooting positions or shooting at more extreme angles may require LOP setting adjustments, even when the same shooter is behind the trigger. These adjustments can be as simple as subtly moving the gun mount or taking advantage of an adjustable stock if the firearm has one. Shooting at extreme angles (like shooting uphill) can also leave a shooter susceptible to scope bite, especially if they haven’t set up a very secure and solid mount. Again, the value of positional dry-firing comes into play in order to properly and safely iron out these details.

The pain and embarrassment of encountering a scope bite is easy to avoid. They just need to be spatially aware and understand that their body works naturally with their firearm, they need to know what good eye relief looks like, they need to tinker and find the right place for the physical placement of their scope and they have to make sure their gun stock fits them so that they can then put their face in the right place to have a clear sight picture. All of these factors work in tandem, and taking them into account will not only dampen scope bite, but contribute to solid consistency in marksmanship.