Most shooters don't give a hoot about the mechanical calculations required to determine a gun's recoil force, but they are concerned about reducing felt recoil, or kick. It's fairly easy to understand when you know what's involved. There is only one factor that your body reacts to, and that's what's known as unit stress. Stress is simply the force divided by the area resisting the force (we commonly use PSI). The greater the area you have resisting a specific force, stress and kick are reduced. There is also another, often overlooked, factor involved which is time, or the duration of the event. Time makes the difference between a punch and a push.
There are some basic ways reduce kick:
- One way is to maximize the gun's contact area with your body. This is were a proper fitting stock is important. You want the recoil to be balanced across the body parts that are in contact with the gun -- taking the majority of the recoil in your face is no fun. Your goal is to have the recoil absorbed by as much tissue as possible. A proper fit must be accompanied by a firm grip in the gun.
- As my friend oneounceload mentioned, reducing the load (mass and/or velocity) and/or increasing the gun's weight will reduce recoil and kick. But, this can be taken to the absurd -- who want's to shoot a 20-pound BB-gun?
- Recoil can be reduced by energy energy absorption and/or redirection. Porting and compensators redirect some of gas energy. Other devices convert recoil energy to other forms (heat).
- The most effective way to reduce kick is by buffering, or increasing the time involved. While elastic materials, inertia masses, air cylinders, and springs may convert a little energy to heat, they are most effective in increasing the recoil event. They effectively turn the recoil punch into a push.
- Another factor to consider is basic geometry. The higher the bore line is above the butt plate, the more the gun will want to rise the muzzle. A stock with a lot of drop may be the reason you're getting whacked in the face.
When I started competitive shotgunning (after many years of casual shooting), the cumulative kick from more rounds got me looking for some help. After trying various methods, I finally found relieve using air cushion systems. A key factor with these rigs (JS and Shockmaster) is the cheek contacts the gun after the buffering (telescoping stocks). Some of the other systems buffer your shoulder, but not your face.