Pattern your gun for POI
Posted: Mon Apr 05, 2010 7:53 am
Do you know where the center of your pattern will impact at the distance you shoot targets, regardless of what type they are? If you don't, you may be missing shots you could be hitting.
"POI" stands for point of impact. It is where the center of the pattern impacts a target. If you are looking down the surface of the rib (or along the receiver and beyond the front bead if there is no rib) and are pointing at a target, the center of the pattern will usually arrive where the barrel is "aiming," actually, the point on a target covered by the front bead.
This "sight picture" (eye, front bead, target relationship) is known as the POA (point of aim). We know that shotguns are rarely aimed like rifles but each time we point the barrel at something, we fire when we see the "right" sight picture. This is the relationship of the front bead or barrel to the target.
This is all well and good until we realize that so far, we have overlooked the third point that creates a sight picture, the eye. The shooter's eye acts like the rear sight on a rifle. When it is moved or adjusted, the point of impact of the bullet (or pattern) moves or changed in the same direction - raise the back sight on a rifle and the bullet will impact higher then it did before the adjustment.
So it is with a shotgun. The point is that unless you shoot rising targets like trap targets, your eye should be looking nearly straight along the surface of the rib. If you are looking down onto the rib with your eye above the level of the rib, your gun will shoot higher than you expect.
If you are looking at the rib from the side, even slightly, your pattern will move in the same direction as the side of the rib from which you are viewing the rib, e.g., look at the rib from the left, and the pattern will impact to the left of where your sight picture suggests.
The point of all this is that you must be looking down the surface of the rib when you fire to accurately determine where you can expect the pattern to go when you shoot.
Things can change with double-barreled guns. They are designed to place their patterns to the same point (their POI) at a designed distance. This is the barrels' regulation. And sometimes it is actually the case. The barrels' POI might be the same at a given distance, usually near 40 yards.
Often they are not, however. They may be off by as much as 12 inches (.3 m) or more. This means that shooting one barrel will put the pattern in a significantly different place that the other barrel. There is little that can be done to correct this problem but you should be aware of it.
How can you become aware of it? Pattern your gun for POI (point of impact). Patterning will tell you where your gun will puts the pattern(s) when you shoot.
To pattern for POI shoot your gun like a rifle, carefully squeezing off each shot. Shoot, using a good rest, something on which to rest the barrel when you aim each shot. Shoot at a distance of 13 meters or yards because at this distance it is easy to locate the center of the hole made by the pattern. Depending on the choke in your gun, the center of the hole will be torn away by the shot or will nearly be.
Shoot at pluses (+) drawn on boxes or a sheet of pattern paper. If using pattern paper, draw four pluses on the paper about a foot (.3 m) apart. Shoot four shots aiming each one carefully, then measure the distance from the plus to the center of the hole made by the pattern. Average the distances from the pluses. This average is the POI of your gun or particular barrel at 13 yards or meters.
The next thing that needs to be determined is where the pattern will be at your normal target shooting distance. To find this, divide the normal target distance by 13 meters. Then multiply that answer by the average distance from the plus to the center of the holes when you patterned the barrel. This is your approximate POI at 40 meters.
If your gun has one barrel, you may be able to move your eye's position relative to the rib when your gun is mounted in a direction opposite the direction the POI pattern varied from the gun 's point of aim. Move it the right distance and the gun's POI will be the same as its POA. This is an over simplification but it can often be done.
Just as your gun's POI can be changed by changing the position of your rye relative to the rib when you shoot, the POI will also change (without you knowing it) if your eye changes position during swings to targets.
This is a good reason to check your gun mount by checking your eye's position when you shoot pre-mounted shooting disciplines like skeet and trap. Also, do what you can to use a gun mount and swing that will keep your eye's position constant during swings. Swing using body rotation rather than arm-swinging your gun. Mount your gun with the top of the recoil pad on your collarbone just inside of your shoulder joint. Try to shoot using an upright body posture.
These elements of shooting form will promote the eye's staying in the same place relative to the rib during swings. If you miss what you're shooting at, it should be because your sight picture (front bead to target relationship) was wrong, not because your head (and eye) moved on your stock during a swing.
"POI" stands for point of impact. It is where the center of the pattern impacts a target. If you are looking down the surface of the rib (or along the receiver and beyond the front bead if there is no rib) and are pointing at a target, the center of the pattern will usually arrive where the barrel is "aiming," actually, the point on a target covered by the front bead.
This "sight picture" (eye, front bead, target relationship) is known as the POA (point of aim). We know that shotguns are rarely aimed like rifles but each time we point the barrel at something, we fire when we see the "right" sight picture. This is the relationship of the front bead or barrel to the target.
This is all well and good until we realize that so far, we have overlooked the third point that creates a sight picture, the eye. The shooter's eye acts like the rear sight on a rifle. When it is moved or adjusted, the point of impact of the bullet (or pattern) moves or changed in the same direction - raise the back sight on a rifle and the bullet will impact higher then it did before the adjustment.
So it is with a shotgun. The point is that unless you shoot rising targets like trap targets, your eye should be looking nearly straight along the surface of the rib. If you are looking down onto the rib with your eye above the level of the rib, your gun will shoot higher than you expect.
If you are looking at the rib from the side, even slightly, your pattern will move in the same direction as the side of the rib from which you are viewing the rib, e.g., look at the rib from the left, and the pattern will impact to the left of where your sight picture suggests.
The point of all this is that you must be looking down the surface of the rib when you fire to accurately determine where you can expect the pattern to go when you shoot.
Things can change with double-barreled guns. They are designed to place their patterns to the same point (their POI) at a designed distance. This is the barrels' regulation. And sometimes it is actually the case. The barrels' POI might be the same at a given distance, usually near 40 yards.
Often they are not, however. They may be off by as much as 12 inches (.3 m) or more. This means that shooting one barrel will put the pattern in a significantly different place that the other barrel. There is little that can be done to correct this problem but you should be aware of it.
How can you become aware of it? Pattern your gun for POI (point of impact). Patterning will tell you where your gun will puts the pattern(s) when you shoot.
To pattern for POI shoot your gun like a rifle, carefully squeezing off each shot. Shoot, using a good rest, something on which to rest the barrel when you aim each shot. Shoot at a distance of 13 meters or yards because at this distance it is easy to locate the center of the hole made by the pattern. Depending on the choke in your gun, the center of the hole will be torn away by the shot or will nearly be.
Shoot at pluses (+) drawn on boxes or a sheet of pattern paper. If using pattern paper, draw four pluses on the paper about a foot (.3 m) apart. Shoot four shots aiming each one carefully, then measure the distance from the plus to the center of the hole made by the pattern. Average the distances from the pluses. This average is the POI of your gun or particular barrel at 13 yards or meters.
The next thing that needs to be determined is where the pattern will be at your normal target shooting distance. To find this, divide the normal target distance by 13 meters. Then multiply that answer by the average distance from the plus to the center of the holes when you patterned the barrel. This is your approximate POI at 40 meters.
If your gun has one barrel, you may be able to move your eye's position relative to the rib when your gun is mounted in a direction opposite the direction the POI pattern varied from the gun 's point of aim. Move it the right distance and the gun's POI will be the same as its POA. This is an over simplification but it can often be done.
Just as your gun's POI can be changed by changing the position of your rye relative to the rib when you shoot, the POI will also change (without you knowing it) if your eye changes position during swings to targets.
This is a good reason to check your gun mount by checking your eye's position when you shoot pre-mounted shooting disciplines like skeet and trap. Also, do what you can to use a gun mount and swing that will keep your eye's position constant during swings. Swing using body rotation rather than arm-swinging your gun. Mount your gun with the top of the recoil pad on your collarbone just inside of your shoulder joint. Try to shoot using an upright body posture.
These elements of shooting form will promote the eye's staying in the same place relative to the rib during swings. If you miss what you're shooting at, it should be because your sight picture (front bead to target relationship) was wrong, not because your head (and eye) moved on your stock during a swing.