Choke Patterns

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Nick S.

New member
Today I patterned my Mossberg 500a 12 ga., with 4 different chokes. All were Carlsons Extended stainless steel tubes. I fired at a distance of about 25 yds. The 4 chokes were SKT, IC, MOD, & FULL. I built my own stand, stapled a new piece of cardboard to it, and used a large white sheet of paper approx 32" X 36". I folded the paper in quarters, unfolded it & drew black lines on the creases. Then traced a skeet in the center with a larger circle traced from a garbage can lid. The concentration of hits became denser towards the lower half as I went from SKT to Full. I fired 2 shots at each target. When they say cover your target, I guess that means aim a little high.
 
Is there a question there? You correctly noted that your POI is low, assuming you aimed at the center of the small circle. That would suggest that your eye is to low. Is there any chance that you are leaning away from the gun and that your cheek having slid too far back on your drop stock is a bit low in relation to the top of your barrel's rib?
 
You got your procedure a little out of phase. Typically, you don't draw the large circle until after you've fired. The large circle is then drawn around the densest concentration of pellet holes. Then you divide the circle into quadrants and count the holes in each quadrant. The count can give you a percentage of hits in each of the quadrants. From this, you will learn where the pattern center is in reference to the aim point and if the pattern density is uniform.

In an ideal world, the point of aim and the center of the pattern will be concentric and there will be 25% of the pellet holes in each quadrant. Shotgun reviews will often include small graphics depicting a circle divided into quadrants with a number in each and an indication of the aim point.
 
I was aiming dead center and used 25 yds because that's what the range officer suggested when I asked him. I always clean my gun within hours of shooting it so I assume the barrel was in proper alignment. 2 years ago I patterned it at 30 yds with the MOD flush choke it came with. Only 2 holes were made in the clay picture of the pattern target with a concentration of holes high & to the left. I circled those 2 holes & fired again aiming lower & to the right. This only made 4 new holes in the clay outline. As you can see, with the exception of the FULL choke, there's a lot more holes in the clay circle ( I traced a clay). The barrel has 2 brass beads on the rib so my aim was fairly accurate. Then the guy next to me was shooting a new rifle right out of the box. He let me try it. The 1st round told me to lower the sights 2 clicks & the next one was dead center at 50 yds. I can aim pretty good. I think it's a matter of using a field gun vs a gun made for trap & skeet. The barrel is made in Mexico. Could that be a factor.
 
Nick, you might want to have a look at TKM's thread on bead alignment. Some guns shoot low (or high) and changing you alignment may be the cure. By now, you should know your gun's POA vs POI. You're lucky, it's a lot easier to compensate, by bead alignment, for a gun that hits low than one that shoots high.
 
I'm not really using the beads when I shoot trap or sporting clays. I'll just point a little higher my next time at the range which should be this Thursday. I would have thought a gun shooting high would be better. You'd still be able to see both the target and the barrel while tracking. Once you cover the target you can't see how high you're covering it.
 
Yes, a high shooting gun let's you float the target when shooting clays. But we were talking about a gun that patterns low on the board. It's easy to increase the height of the impact by increasing the height of your eye above the front bead. To lower a high shooting gun you have to raise the bead after your eye is as low as possible.
 
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