November 03, 2010
Over loading shotshells with heavy payloads
It can be a complicated subject, but when boiled down, it's the powder and shot that's the real reason many patterns go away, even when a large amount of shot is fired toward the target. I am speaking of a practice used today by way of the industry and handloaders alike. That practice is massively over loading shotshell loads with heavy payloads. The end result is an overbore situation.
The author with a test pattern that indicates an overbore situation. Note the areas between the wavy lines that contain no shot at all. This is the result of a 1 1/4-ounce payload being pushed into a high performance full choked barrel.
In general, the 12-gauge shotgun, being the most used gunning system around as applied to waterfowl, will make the best use of a load consisting of 11„8 ounces of shot. That means that the bore of this gauge is .724 inches, as married to this payload charge, will produce the very best patterns with the least amount of barrel or choke strain.
This payload will also run down range leaving the least amount of blown patterns, ragged fringe edges on the outer perimeter of the pattern, and otherwise poor pattern performance results.
During the grand old days of the eight- and 10-bore waterfowl cannons a charge of about 1 1/4-ounce was considered massive as applied to the 10-gauge wet bird gun, and 1 1/2-ounce was also a major payload even when fired form an eight-bore cannon. I don't know how many of you have ever touched off an eight-bore goose gun, but I have, and I am here to tell you that it is almost a religious experience when that powder goes off. These big guns were about powder charge as much as pellet payload. Did those old super bore sneak boat market hunters know something we don't? I tend to think so.
If many of those mammoth market duck cannons used so little shot, why have we choked the 12-bore to death with overbore charges of steel shot pellets? As I have alluded to already, it is a sales gimmick of sorts in that as the good old American way says, "Bigger is always better, and he who has the biggest load on the swamp wins."
Well, that's not the case all the time. Massive heavy charges of shot don't add up to doing much more than pounding more holes in the sky, or sending more pellets into a mud bank across the river.
Now, before the guy that gets great results from his 3 1/2-inch 10- or 12-gauge loaded to the star crimp with massive charges of steel shot that equal the weight of a deer slug gun turns on me, let me say that yes, there are exceptions to the rule. Like good patterning gun barrels, there are gun systems that do take a liking to big heavy payloads of shot.
If you own one of them my advice is don't sell it, but hunt hard and be well on the marsh for many years to come.
Sadly enough, however, the truth is that most hunters don't pattern the loads that are being taken afield, and when some of those hunters do fire a shot or two down range at paper, they quite often don't have a clue as to what they are looking at anyway.
I hunt with some dedicated duck hunters out here in the far west that I have never seen shoot a single pattern. What these guys do is ask me if the load and choke are workable for the task at hand.
Why is there a problem with over boring a payload in the 12-gauge duck gun?
It amounts to a large mass being squeezed down to small a hole. When this takes place, the shot charge acts like the effects of water from a garden hose and sprays shot all over the place (or at least into clumps that can miss well-centered targets at very workable range limits). This can occur even when shot payloads are a small as 1 1/4-ounce. Drive even this quite standard payload down an ultra tight full choke and the end result can be major gaps in the pattern; large enough to allow a duck to fly untouched straight through.
Way back in the late '60s, I shot bluebill fast movers in north central Minnesota with a 2 3/4-inch 1 1/8-ounce handload of copper lead #5s that was pushing out of the barrel by way of a heavy charge of AL 5. (ALCAN. ) This load depended on the powder charge that was stiff versus a shot charge that was massive. One of the worst conditions I experienced when steel shot came onto the scene was that I was forced to give up this very effective, budget priced duck killer over big water set decoy spreads. While some guys up on the big northern Minnesota lakes shot 10-bore cannons, I shot my lightning fast 11„8-ounce payload, and simply plastered ducks by the limit year after year.
There are several ways to control overbore payload conditions when using these massive payloads of steel, and that is run them out of a choke that is designed to handle them, or use an over sized bore (back boring systems). Recently a good friend wrote me about his results using a tight steel shot safe full choke (.40-point) as paired with 31„2-inch 12-gauge tungsten turkey loads in Winchester Xtended, which counted out to 13„4-ounce payloads of tungsten #5.
I use this shooting event as an example, but be advised it is an experiment only. At $3.50 a pop to send a load into the sky, you won't find me giving this ballistic event a try anytime soon. What's interesting, however, was that by way of some pre-pattern work, and a match to a quality super-full choke in a back-bored barrel, this hunter owned the air space completely. Overbore situation here? Yes, but in this case, quite well controlled.
Ever wonder why the industry worked toward developing the back bore (over-size) barrel? It's because engineers knew full well that steel shot in its massive payloads would require more room to run down a 12-gauge barrel.
More load requires more bore room to settle down and pattern well. the big loads in the 3 1/2-inch and over loaded 3-inch hulls tend to string shot column out a good deal and again as such can add to the overbore big payload situation.
Like my previous review work, hunting extensively with single shot sizes in large steel pellets there is some solid evidence in the ballistic performance area that smaller payloads of shot can produce some positive returns as applied to very quality patterns and also some effective knockdown ability.
During the late 2007 season in South Dakota I elected to give this " go light" program a try by way of budget loads, and as paired with a prototype "Dead Ringer" choke of my own design that makes use of all of the payload almost each and every time. In this case I set out to harvest some ducks, and keep track of my results to the last detail.
One morning I took three birds with three rounds. All shots were within a 35- to 45-yard envelope, and not a hint of a cripple was evident. My birds were all stone dead. Also, be advised that I have never seen common lead perform any better then what took place that morning on that small body of almost frozen water.
During the remainder of the last month of the waterfowl season, my light payload gunning methods accounted for 28 solo birds.
At that time I had sustained two cripples that were retrieved by my partner Lance Lalonde's excellent Chesapeake retrievers, Crocket and Teal.
I had reduced my payload substantially, saved a pile of money in the process via the use of that low budget ammo, and lost nothing in the transition.