Can a Rifle Scope be Used on a Shotgun?

I used Warne Maxima steel scope mounts, made in USA.
Rifle scope. Photo © Russ Chastain

In areas where only shotguns are allowed for deer hunting, hunters often wonder if they can mount a rifle scope onto their shotguns for greater targeting accuracy. While there are scopes made for shotguns you can buy, the variety available for rifles is much greater, or hunters may think it's just as easy to swap out a rifle scope onto the shotgun for deer-hunting season. But is this feasible?  The common belief is that a rifle scope won't be likely to stand up to the recoil of a shotgun, but it turns out that there are other, perhaps better, reasons to avoid this tactic.

 

Shotgun Recoil

A 12-gauge shotgun can kick like a mule, but it's generally a different type of kick, with a longer push. Yet it can sometimes be sharp and hard recoil, as I experienced when shooting Brenneke 1 3/8-ounce slugs, which produced possibly the hardest kick of any long gun I had fired at the time. And when it comes to foot-pounds of recoil, a 12-gauge can generate much more than the average deer rifle—even matching some of the large African dangerous-game cartridges.

The reason for this is not hard to understand. Shotgun slugs, which are usually what's used with scoped deer-hunting shotguns, are big and heavy. The recoil associated with them is anything but light. A-12 gauge shell is roughly 70 caliber, which naturally will have substantially more kick than, for example, that of a 30 caliber rifle. Simple physics tells you that the larger the projectile that accelerates out of the barrel, the more backwards force will be present.

This also applies to many sabot shotgun slugs, which shoot reduced-diameter projectiles in plastic sabot sleeves of 12-gauge diameter.

This means that a shotgun's recoil can indeed beat the heck out of a rifle scope. But potential damage to the scope is not the main consideration. 

The Real Problem

Recoil aside, the main thing to consider is that the biggest difference between shotgun scopes and rifle scopes is eye relief—the distance between the shooter's eye and the eyepiece of the scope.

Because the standard rifle has a shorter recoil, scopes designed for rifles have a shorter eye relief that puts your eye rather close to the eyepiece. Shotgun scopes, on the other hand, taking into account the longer kick of the weapon, are designed with a longer eye relief to accommodate the deeper recoil of the gun.

When you mount a rifle scope on a shotgun, you are forced to place your eye too close to the scope, and upon firing, the recoil is likely to kick back far enough to strike you forcefully in the eyebrow. Deep cuts and lots of blood are not uncommon, and if you see a hunter with a deep, crescent-shaped eyebrow scar, you very likely are looking at a hunter who learned this lesson the hard way. 

Your best bet is to put a shotgun scope on your shotgun, and keep your rifle scope on your rifle.