Shot Talk

It seems that lately it’s been popular to knock the 3" 20 gauge. I find Internet bulletin boards and even some shotgun writers’ works replete with pronouncements such as “The 3" 20 gauge doesn’t pattern well,” and “It’s hard to get the 3" 20 gauge to perform.” I’ve even read the convoluted argument that the 3" 20 gauge is inherently inferior to the 2-3/4" 20 gauge, so one may as well buy a 28 gauge, seeing as the only reason to buy a 20 is to have a 3" version.
    In reality and from my empirical testing, these statements are decidedly unfounded. They ring true only if you believe what you hear or read on the Internet and if you’ve done little or no testing. So let’s look objectively at the 3" 20 gauge and see what it is—and is not—capable of doing well.
    First reality: The 3" 20 gauge is not a substitute for the 2-3/4" 12 gauge. I make this point because in the development and promotion of the 3" 20 gauge, also known as the 20-gauge magnum, shotshell manufacturers billed it as the equivalent of the 2-3/4" 12. The marketing hype was that by owning a 20-gauge chambered for the new 3" 20-gauge magnum cartridge, one could have a light upland gun that would handle 2-3/4" loads beautifully and also could be used for heavy-gamebird shooting at long range (read pheasants and waterfowl). Some gun writers told us it could do everything on such birds that the 2-3/4" 12 gauge could but in a much lighter gun. My testing through the years, however, tells me that such claims overreached.

Ballistics
First, in terms of payload capacity, neither the 3" nor the 2-3/4" 20 gauge can hold as much shot as the same-length shells in either the 16 or 12 gauge. Yes, I know there is no 3" 16-gauge load, but bear with me. The fact is that 1-1/2 oz of lead shot can be stuffed into the 2-3/4" 12 gauge, and these days a full 2 oz of lead shot are being stuffed into the 3" 12 gauge. In contrast the 2-3/4" 20 gauge can hold at most 1-1/8 oz of lead shot, and the 3" 20-gauge magnum can hold at most 1-1/4 oz. So there is no way that the 3" 20 gauge can match the shot-charge capability of the 2-3/4" 12 gauge. The 3" 20 gauge can, at best, match the 2-3/4" 16 gauge, in which 1-1/4 oz of lead shot remains the heaviest current loading.
    Second, there’s the matter of velocity. Because as gauge size (and therefore hull capacity) decreases pressure increases, a given payload weight in 20 gauge can never be launched at as high a velocity with as low a chamber pressure as it can in a larger gauge. We could develop propellants to achieve velocity without adding pressure, but the same propellants also could be used in the larger gauges. The smaller gauges simply cannot beat the larger gauges when it comes to velocity/pressure ratios. So although it is true that you can buy or reload a 1-1/8-oz 2-3/4" 20-gauge or 1-1/4-oz 3" 20-gauge lead load, you never will match the velocity levels attainable at safe pressure levels in these loadings as those attainable in the larger-capacity 12- or 16-gauge loads.
    Third, there’s the matter of patterns. If we’re talking about soft shot types like lead, bismuth, Nice Shot, ITX or any of the tungsten/plastic composites, it is generally true that one cannot get 2-3/4" 20-gauge 1-1/8-oz or 3" 20-gauge 1-1/4-oz loadings to pattern as efficiently (at a given distance through currently obtainable chokes) as the same load weights in 2-3/4" 12- or 16-gauge shells. This is for the same reason that it is difficult to find 2-3/4" 16-gauge 1-1/4-oz lead loads that pattern as well as 23/4" 12-gauge loads of the same weight.
    Why? Because all patterns with soft shot types are a function of pellet protection. The better the pellets are protected, the less pellet deformation will result and the higher the pattern values will be. The ballistic maxim is: Regardless of gauge and assuming spherical projectiles, equal choking and reasonable (not hyper) velocity levels for any given shot-charge weight, the higher the percentage of round pellets that emerge from the muzzle, the higher the resulting pattern efficiency. The corollary is that the more pellet deformation there is, the poorer the patterns will be.
    So if those knocking the 3" 20 gauge find it not patterning well, it’s because the loads of soft shot types they are testing invariably feature a very heavy shot charge that cannot be protected as well as the same shot charge in a larger gauge. And, no, it really doesn’t have anything to do with the antiquated, so-called square-shot-charge theory. The square-shot-charge theory proved only fairly accurate when we were dealing with low-antimony lead shot not encased in modern plastic shot containers.
    With today’s high-antimony lead shot, however, the only reason a given load in a smaller diameter like the 3" 20 may not pattern as well as you’d like is because you’ve selected a load where the hull has been stuffed so full of shot that there isn’t enough room left to properly protect the pellets from deformation. Just cut apart any 3" 20-gauge 1-1/4-oz lead load and you will see what I mean. See that shot cup or shot wrapper? It doesn’t fully contain the lead pellets, does it? That means that all of the pellets sitting above the top of the shot-protection device are vulnerable to bore-scrub deformation. See that cushioning section below the 11/4-oz shot charge? It’s pretty thin and puny—maybe even nonexistent. And such thin cushioning sections can never prevent as much setback deformation to the bottom of the shot charge as can thicker cushioning sections.
    So the solution to achieving good patterns with the 3" 20 gauge is to stay away from 1-1/4-oz loads of soft shot types. From my pattern tests, the maximum lead-shot charge that will pattern well in the 3" 20 gauge is 1-1/8 oz, with 1 oz being even better. The other key with the 3" 20 is to be sure to select factory loads or reloading data that feature full containment of the soft-shot charge. You also want to be certain to search for thick cushioning sections below the shot charge. With lead, insist on loads featuring the highest-antimony shot. And if the lead pellets are truly copper- or nickel-plated as well, so much the better. Even with the lighter loads, one must also be careful to select loads that use propellants that are as slow burning as possible in order to launch the pellets as gently as possible. Last, choose only soft-shot loads that have modest instrumental velocities of 1,250 fps or slower. In combination, all of these loading and ballistic details will help minimize deformation to soft shot types as well as reduce muzzle blast and the aerodynamic resistance of the pellets, resulting in the best possible patterns.

Hard Pellet Loads
All current hard pellet types being loaded in the 3" 20 gauge are nontoxic. The best known of these are steel shot, most of Environ-Metal’s HEVI-Shot products, Federal’s Heavyweight shot, Remington’s Wingmaster HD shot, and Winchester’s Xtended Range Hi-Density shot. With these 21st Century loads you pretty much can ignore all of the above discussion about getting the 3" 20 gauge to pattern well. Nothing has done more to improve the pattern quality and lethality of the smaller gauges than the development of hard nontoxic-shot types. Load hard, non-deformable pellets in the small gauges, and patterns will make a quantum leap over those obtainable with soft shot types.
    Here are some examples: Assuming a decent choke constriction of conical/parallel configuration for the shot size being tested, you can regularly enjoy 80-plus-percent 40-yard patterns from steel-shot loads in the 3" 20 gauge. Many shooters are overjoyed to discover 90-percent-or-higher patterns with current 3" 20-gauge hard tungsten-composite loads. And because none of these hard pellet types deform, you can absolutely stuff the 3" 20 gauge full of shot and worry nothing about saving space to cushion the pellets. It is still true, however, that you can’t get carried away with hyper velocity levels in 3" 20-gauge hard-shot loads if you want the best patterns. My pattern testing has revealed that—especially with steel shot—nothing higher than 1,300 fps is needed or will pattern better in sub-gauge hard-pellet loads.
    The above are the general ballistic truths and my empirical findings—representing literally hundreds of pattern tests and thousands of rounds fired—in developing both factory 3" 20-gauge loads and 3" 20-gauge reloading data. Next time I’ll present pattern-test results, factory-load recommendations and select reloading recipes for lead and nontoxic shot types that make the 3" 20 gauge shine.

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