Shot Talk

One of my favorite books is Stanley Coren’s The Intelligence of Dogs, which discusses canine consciousness and capabilities, the cognitive abilities of various breeds of dogs, and differences in personalities of dogs within breeds. It inspires the notion that someday I may write a book on the intelligence of shotgunners. Believe me, judging from the correspondence I receive, SSM readers will be at the top of that list—the border collies of our species. Following are just a few examples of the technical issues about which I’ve been contacted.

Shotgun Loudness
Several thoughtful SSM readers have concerns about the loudness of reports—commonly referred to as “muzzle blasts”—made by shotguns. These readers would prefer quieter reports (for reasons that include their hunting situations or the fact that they practice at ranges that are trying to keep peace with their neighbors) without going to subsonic loads of less than 1,100 fps.
    The loudness of muzzle blast has more to do with the velocity and burning rates of propellants in specific loads than it does with gauge. Generally speaking, the higher the velocity of a given-weight shotshell load, the louder the muzzle blast, simply because it exceeds the speed of sound by more. Also, generally speaking, the slower the burn rate of the propellant, the louder the muzzle blast, because the blast is emitted at a different sound frequency. Regardless of gauge, very-slow-burning propellants are usually necessary to achieve 1,300-fps-or-faster velocities at safe pressure levels, assuming a heavy or magnum load for the gauge and shell length.
    It is incorrect to assume that the smaller gauges produce less muzzle blast than the larger gauges simply because of their size; the heavier and/or faster loadings will develop more muzzle blast regardless of gauge. For example, 2-3/4" 20-gauge 1-oz lead loads are seldom faster than 1,200 fps. They do not produce as much muzzle blast as heavier 12-gauge loadings of the same pellet type that are loaded to produce faster velocities. Pushing increasingly heavier loads at a given velocity level generally requires slower-burning propellants than lighter loadings or slower velocity levels; So, yes, there is more muzzle blast from today’s heavier and/or faster 12-gauge loads than smaller or same-gauge loads of the same shot type. But the decibels of muzzle blast are a function of how the load breaks the sound barrier (sound frequency) and then by how much the load’s muzzle velocity exceeds the sound barrier, rather than a function of gauge.

Accurate Powder and Shot-Charge Weights
The results of the survey I ran about six years ago revealed that at least one-third of SSM readers reload. Very smart. Reloading is the best way to get exactly what you want in a shotshell load. Since the printing of my Shot Talk column titled “Useful Tools” (Nov/Dec ’08), many readers have told me that they have been pleased with the electronic scales they have purchased. They have found them to be much faster and more accurate than balance-beam scales.
    But in the process of using them, many started discovering that reloading bars and bushings seldom drop the exact quantities specified in manufacturers’ tables. Are these manufacturers incompetent, or what? Absolutely not. It is common for charge bars and bushings not to throw exactly as they are listed. Charge-bar and bushing charts must be considered listings of close approximations only.
    The reason is that shot-charge bars and bushings are set up with one particular shot size and therefore throw accurate charge weights with that shot size and one smaller or larger. As one moves away from that range of pellet sizes, the actual weight thrown will vary. Generally, the larger the pellet size thrown through a charge bar or bushing, the lighter will be the weight thrown. Similar to different-size shot, some propellants are coarser grained and so naturally display larger throw-to-throw powder-weight variations than finer-grained propellants. In addition some reloading benches wiggle more than others, and some reloaders are much more heavy-handed in operating their presses. These things add up to variations in vibration, which affects the amount of shot or powder that ultimately drops by gravity into the bar or bushing cavities. For these reasons, bar or bushing manufacturers cannot absolutely guarantee the charge weights listed in their tables.
    One solution with MEC presses, for example, is to abandon the MEC charge bars for a charge bar that’s adjustable for both shot and powder charges. One such bar is called the Universal Charge Bar, manufactured and sold by Multi-Scale Charge, Ltd. (905-566-1255; www.multiscalecharge.com). With this adjustable bar, the reloader literally can dial and set powder-charge weights of plus or minus .3 grain and shot-charge weights of plus or minus 20 grains—regardless of shot size or type.
    For presses for which adjustable charge bars are not available, you must strive to reload on a sturdy bench and operate the press handle with the same amount of vigor on each stroke. Progressive presses automatically will give you more uniform powder- and shot-charge weights than single-stage presses, because they operate with less and more consistent vibration. Keep careful records of your shot- and charge-weight findings, and use the bar and bushing charts as guides to get you into the ballpark only.

Round Pellets
There are many longstanding beliefs about what constitutes the best projectile shape for shotshell pellets. The answer is that if you want open patterns, you want non-round projectiles—cubes would be best. If you want tight, long-range quality patterns, then bullet- or teardrop-shaped projectiles are best. But let’s face it: Most shotshell projectiles we have been given over the years are something approaching round. In the case of certain nontoxic pellets like steel or Wingmaster HD, for example, the round pellets are highly spherical and uniform. But what about the surface quality of these round projectiles?
    The popular perception is that round, smooth shot flies the truest and therefore patterns best. The ballistic reality is that this is not true. Dimpled round shot would fly truest to the point of aim, which is why golf balls are uniformly dimpled. (The dimples break up any vacuum that  may form on any given side of a round projectile as it travels through the air. If a vacuum forms, it causes the projectile to move in the direction of the vacuum. Uniform dimpling causes air to flow evenly around all facets of the round-shaped object, which greatly assists it in flying straight.) It would, of course, be exorbitantly expensive to try to build a uniform dimple pattern into shotshell pellets. It would have to be done by molding each pellet, and this would be only remotely cost effective in the largest shot sizes.
    What about bullet-shaped shotshell projectiles? We have them only in slug loads. How about teardrop-shaped projectiles? We have them in HEVI-Shot—not by design, but by an accident of the process by which Environ-Metal forms its high-density, hard HEVI-Shot pellets. The process leaves little blobs stuck to many of the ball-shaped pellets, and it is this form that accounts for why HEVI-Shot pellets tend to pattern better than smooth, ball-shaped projectiles. The teardrop, in effect, acts like a boattail on the pellet. Boattails stabilize projectile flight, reduce drag and significantly help projectiles fly straight.
    Another projectile shape that would fly true to point of aim would be a small dart, such as the steel flechette shotshell load used in the Vietnam War. But that’s another story, and such projectiles are far too deadly for safe sport-hunting purposes.
In the final analysis, the projectile shape you choose should depend a great deal on the patterning performance you prefer. Because there is a wide variety of projectile shapes out there, the wise shotgunner will learn about them, pattern test them and go forth with what works best for the particular purpose, whether it be target shooting or hunting.

To correspond with Tom Roster or to order his reloading manual on buffered lead and bismuth shotshells, his HEVI-Shot reloading manual, his newly updated 75-page Shotgun Barrel Modification Manual or his instructional shooting DVDs, contact Tom Roster, 1190 Lynnewood Blvd., Klamath Falls, OR 97601; 541-884-2974; tomroster@charter.net.