One of the most important things you can do to improve your shooting is to take your shotgun to the pattern board and do some impact testing. I am always surprised at the number of shooters that have never done this. Some struggle with their shooting, others wonder why they chip a lot of targets and seldom get that hit where the target just disappears. I stress to all my clients the importance of impact testing, no matter if it's with a gun that they have shot for years or one they just purchased.
Grease Pattern Board
As the name implies, we are looking at where the mass of shot impacts the pattern board. I like to start at 16 yards from the pattern board and use an "improved cylinder" or "light modified" if the barrels have interchangeable choke tubes. I start by rifle shooting the shotgun by stacking the beads and making sure that I see that "figure eight" and letting the shot go. I do this first for every so often, I'll find a gun whose barrels are mis-regulated and have to be sent back to the factory for adjustment. An owner of one such gun came to me for a gun fitting for he was getting frustrated with his shooting. His scores where down and could not improve on them despite all his practice and advice from friends. When we impact tested the gun at 16 yards, stacking the beads, the center mass of the shot was 8" below the center target, imagine where is was on a 40 yard shot! All of his aggravation could have been avoided if when he first purchased that gun, he went to the pattern board and did some impact testing.
Inconsistent Gun Mount
Also you can tell how the barrels are regulated, 50/50, 60/40, even 70/30. When you see that relationship from the end of your barrel to where the shot is impacting the board, it gives you a sight picture that you can store in your brain and use when you call for a target. Case and point, I used to shoot a Beretta 686 for a long time and shot it well. I later decided to get a Krieghoff K-80, I remember the first time I took it to my local club to try it out. I was all excited about my new gun, but very soon my excitement turned to disappointment for I could not hit targets like I did with my 686. I had people standing behind me telling me that I shooting below the target, some said I was shooting over it, one even said that I needed to get a different hangar for the bottom barrel. To say the least, it was a frustrating night. The next day I went to the pattern board and did some impact testing. From the very first shot I found my problem, the K-80 shot flatter than my 686. I put that sight picture into my brain and it was like someone flicked a switch for I started smacking targets from that point on.
Consistent Gun Mount, Bad Stock Fit
After your rifle shot and confirming your barrels hit properly, it's time to take shots as if you where shooting at a flying target. If you shoot low gun or pre-mounted doesn't much matter, just look at the target, put the gun up and take the shot. Take 6 or 8 shots to begin with, don't make a determination by just one shot. This will tell you how your fit and gun mount is. If the point of impact is all over and inconsistent, you need to practice your gun mount more. If your impact is in the same place all the time, you will then be able to determine if your gun is impacting where you want or if some adjustments need to be made to your stock.
Consistent Gun Mount, Good Gun Fit
So do yourself a favor and head out to your local patterning board. All in all, it is time well spent for everyone, from those who have only one shotgun, and especially for those who shoot many different ones. A little bit of time could help you pick up a few more targets!