By Tom RosterI have been conducting and publishing scientific tests and writing about the technical aspects of shotgunning for more than 45 years. During this time I always have assumed that technical knowledge about shotgun loads, chokes, ballistics and gun-damage issues would advance.
Alas, judging from my interactions with shotgunners, I have found that limited progress has been made. Most shotgunners I talk to get their information principally from hearsay, rumor and, I’m sorry, the generally dreadful videos and chat-room discussions on the Internet that often are dominated by self-styled experts who present no credentials and test data or studies for evaluation.
As a result, certain shotgunning myths that should have died ages ago continue; plus there is a crop of new misinformation and untruths. Following is a quick rundown of the dominant “issues” I typically find.
Whether your choke choices are integral or screw-in, it doesn’t matter if they are extended (stick out of the barrel) or flush-mount. All that counts is their overall length and internal configuration. For less than 40-yard shooting, my tests have never found that choke length really matters. But for shooting beyond 40 yards, my tests clearly have found that chokes 2½" or longer tend to produce tighter patterns, especially with shot sizes US No. 5 and larger. This is because such length allows for more gradual tapers for the choke run-in and longer parallel sections once the desired choke internal diameter is reached. Also, an indisputable finding by every individual I have ever read who actually has conducted extensive pattern testing is that every choke with its designated constriction tends to pattern best one shot type and one shot size at one velocity range. So just because a particular choke is found via pattern-testing to do great with No. 6s, for example, it doesn’t mean that it will pattern well with No. 4s and so on. Also, you have to explore different velocities in 50-fps increments to find the velocity range that your choke tends to pattern best with its preferred shot size.
Wad Stripping and Porting
Two contemporary and often exaggerated shotgunning claims involve so-called wad-stripper chokes and barrel or choke-tube porting. Add-on devices and choke tubes that are said to “hold back the wad” and thus greatly improve patterns are still being hawked. I have done extensive high-speed-photography testing on such devices. None have proved to hold back the wad. In every case, upon muzzle emergence the shot clearly has been seen to still be fully contained inside the shotcup. For nearly eight years I have challenged manufacturers to provide photographic evidence of their claims. I have yet to receive any.
As to porting, the claim often is made that port holes in a barrel or choke tube “reduce recoil.” Ports cannot and do not reduce free rearward recoil. If, however, three or more inches of ports are properly installed on the top of a barrel (not just the ½" to 1" available on an extended choke tube), muzzle jump can be reduced. Ports on the sides or bottoms of barrels or choke tubes do nothing positive and greatly increase muzzle-blast noise. Those on the bottom actually increase muzzle jump. All provide more points for water entry and plastic buildup from wad passage.
It saddens me to report that lead-shot quality in many factory loads and reloading shot generally has been diminishing. This has become evident the past three years in my tests of shot-hardness levels. Observant buyers have noted that the antimonial levels formerly printed on the boxes of many factory loads and bagged shot have disappeared. Actual antimony percentages have been replaced by words like “hard,” “extra hard,” “magnum” and “premium.” SAAMI has no antimony standards for any such words on US-made lead shot except “hard.” As long as the lead shot contains ½ percent or more of antimony, SAAMI allows the word “hard” to be used. Other hardness words can mean anything the manufacturer wants. In lieu of actual antimony levels being clearly indicated, chances are that the lead shot you’re buying now is softer than it used to be.
Unfortunately, as long as shotgunners are unwilling to pattern-test or even cut apart shotshells to visually examine or better yet actually test shot for hardness, they will continue to shoot ammunition without really knowing what they are using.