Dear Technoid,

Could you please provide some perspective on shotgun shell shot string? Specifically, the effect of velocity on shot string, the effect of the amount of shot on shot string, the pros/cons of shot string, the effect of shot hardness on shot string, differences between gauges on shot string. For example, I am operating under the premise that a short shot string is good since you want as much as possible of the shot to arrive at the target at the same time (in order to fill a 30″ pattern around the clay target). I have been told that 7/8 oz. 12 gauge loads pushed at high velocities (i.e., 1400 fps) significantly increase a shot string versus a 1 oz. 12 gauge load pushed at 1200 fps.

There is also a differing point-of-view that a long shot string is good because it allows for greater “shot placement error” (i.e., the clay can be hit anywhere along the shot string, so a long “cloud” is better than a short “cloud”). There is also the guidance that beyond 40 yards, hard shot (i.e., with 4-6% antimony) produces less “flyers” and, therefore, a tighter, more dense shot string. But does harder shot have any impact on the shot string length?

The goal is to identify a retail-available (I don’t reload) 12 gauge shell with low recoil and a dense pattern (with appropriate chokes) at any clay target shooting distance, and understand why the shell is delivering this performance. I want the shell to contain 7 1/2 shot (for retained pellet energy). And yes, I know that there are more pellets per ounce if 8’s are used, but my goal is one shell in my pouch, and it is my belief that there are clay targets that 7 1/2 shot will break but 8 will not.

Thank you,

John

Dear John,

I can’t tell you much from personal experimentation with shot string as I have never devoted the time and treasure to perform the tests required to understand it on a first hand basis. As usual, I steal my best ideas from my betters. Bob Brister’s seminal 1976 book “Shotgunning, The Art and Science” (Amazon should have some) is probably the most complete and readable discussion of shot string published to date. Brister simply got his wife to tow a trailer with a large sheet of plywood and pattern paper past him as he shot his patterns. It was remarkably effective in showing the different shot strings and in testing the strength of the marriage.

The most modern setup was by Dr. Giblin when he was working for the British in developing non-tox loads. He worked at the H&H facility and used a series of chronographs and an impact sensing pattern plate also hooked up to a computer. He could actually time the separate pellet impacts and thus restructure the shot string of that shot. We corresponded a bit concerning these experiments.

On a 40 yard 90 degree crosser, shot can string as much as 8~12 feet and can reduce your 30″ circle pattern by 25% in some cases. Of course, as the angle lessens from 90 degrees, the shot stringing also effectively lessens until it becomes zero on a going away or directly incoming shot.

The main cause of shot stringing is deformed shot. The more out of round shot is, the more it will lag behind its rounder brethren as if flies down range. What ever you can do to lessen deformation will lessen shot string. That includes shot buffering and improved wads/powders, lower shot velocity, larger bores, longer cones and definitely harder lead shot. Shot string isn’t always bad. In 12 gauge American-style skeet where you have more #9s than you need, shot string effectively makes your pattern larger. In all other cases, shot stringing dilutes the pattern and makes it effectively smaller.

As to gauges, it all comes down to shot deformation again. the 3″ .410 is brutal to shot and the long shot strings show it. 7/8 oz from a 12 gauge will pattern better with a shorter shot string than it will from the 20 ga or from an overloaded 28.

I’ve spent some time chatting the Jay Menafee, the resident genius behind Polywad. Jay has extensive experience with buffered shot and reports significantly improved patterns due to lower pellet deformation. This also true with Tom Roster’s earlier experiments with less sophisticated buffering which showed shorter shot strings. Winchester’s very early experiments with buffering also showed this. It’s not brain surgery. Anything you can do protect the shot or subject it to less abuse during launch will result in less deformed shot and thus a shorter shot string and a more consistent pattern.

And here’s something you probably didn’t reason out. I sure didn’t. Open chokes string MORE than tight chokes. Many people have said just the opposite, but Brister quotes a good bit of research proving his point.

So, what shell to use? I’d use the one with the hardest shot and lowest velocity that will do the job. Skip the fast hot rod loads as they deform more shot than the same pellets used in a slower load. A high quality 2-3/4 dram 1-1/8 oz target load of #7-1/2s would be ideal. Federal Premium Gold Medal Target and Remington STS come to mind. The longest shot strings will come from the “promo” dove and quail loads. They have high speeds and use soft shot..

Let me know what you pick. I’d be interested in what your experiments show.

Best regards,
Bruce Buck
Shotgun Report’s Technoid