People reload ammunition for different reasons. \u00a0 It used to be you could save money by reloading, and I suppose for the more exotic cartridges (any Weatherby ammo, the big elephant rounds like .458 Win Mag, the .416 Rigby, etc.) that’s still the case.\u00a0 It’s not the case for the more common rounds like 9mm, .45 ACP, and .223 Remington; bulk ammo for those is so inexpensive you’d be hard pressed to reload for as little as that ammo costs.\u00a0 Sometimes people reload because factory ammo is no longer available or it’s very tough to find.\u00a0 But most of us reload for accuracy.\u00a0 We can experiment with different combinations of components and tailor a combo to a particular firearm to find the sweet spot…that combination of components that provides the tightest groups.\u00a0 I’m in that category; it’s why I reload.<\/p>\n
When I’m testing for accuracy and I get a tight group, I always wonder:\u00a0 Is it because of the combination of components, or is it just a random event?\u00a0 Usually, if the group size is repeatable, we conclude that it is the component combination, and not just a random good group that results from all the planets coming into alignment.\u00a0 But is there a better way? \u00a0 You know, one that shows with more certainty that it’s the component combination, and not just a fluke?<\/p>\n
This article is a bit different.\u00a0 It’s not just a story about a gun or about reloading ammunition.\u00a0 It includes those things, but it’s more.\u00a0 This story is about applying the Taguchi design of experiments technique to .45 ACP load development for ammo to be used in a Smith and Wesson Model 25 revolver (the one you see in the photo above).<\/p>\n
I’m guessing you probably never heard of Taguchi.\u00a0 That’s okay; most folks have not.\u00a0 Taguchi testing is a statistical design of experiments approach that allows evaluating the impact of several variables simultaneously while minimizing sample size.\u00a0 The technique is often used in engineering development activities, and I used it regularly when I was in the aerospace world.\u00a0 The technique was pioneered by Genichi Taguchi in Japan after World War II, and made its way to the US in the mid-1980s.\u00a0 I used the Taguchi technique when I ran engineering and manufacturing groups in Aerojet Ordnance (a munitions developer and manufacturer) and Sargent Fletcher Company (a fuel tank and aerial refueling company).<\/p>\n
Taguchi testing is a powerful technique because it allows identifying which variables are significant and which are not. \u00a0 Engineers are interested in both.\u00a0 It lets you know which variables you need to control tightly during production (that is, which tolerances have to be tight), and it identifies the others that are not so critical.\u00a0 Both are good things to know. If we know which variables are significant and where they need to be, we can change nominal values, tighten tolerances, and maybe do other things to achieve a desired output. If we know which variables are not significant, it means they require less control. \u00a0 We can loosen tolerances on these variables, and most of the time, that means costs go down.<\/p>\n
Like I said above, I used Taguchi testing in an engineering and manufacturing environment with great success.\u00a0 The Taguchi approach did great things for us.\u00a0 When I worked in the cluster bomb business, it allowed us to get the reliability of our munitions close to 100%. \u00a0 When I worked in a company that designed and manufactured aerial refueling equipment (think the refueling scene in the movie, Top Gun<\/em>), it helped us to identify and control factors influencing filament-wound F-18 drop tanks.\u00a0 In that same company, it helped us fix a 20-year-old reliability problem on a guillotine system designed to cut and clamp aerial refueling hoses if failures elsewhere in the refueling system prevented rewinding the hose.\u00a0 You don’t want to land in an airplane trailing a hose filled with JP4 jet fuel.\u00a0 Good stuff, Taguchi testing is.<\/p>\n