At 17 11 05, 04:12 PM, Remek Kocz wrote:
You're talking about airsoft BB's, right? I've seen them in the 6.0 mm/0.12 g designations at Gander Mountain. Never saw any USC units, even in parentheses. However, once I walked over to the shotgun shells, the reality set in, as everything was in inches and (!!) grains. Some manufacturers did list the shell lengths in milimeters, but that was a rarity. There is an industry that we can pester about including metric information on their products.
The firearms & ammunition industry is like the printing industry: slowly metricating, but so thoroughly steeped in a variety of oddball units that it will take awhile.
For example, when you buy 9 mm rounds, the bullet weights are listed in grains. Winchester lists their Russian 7.62 round as "7.62x39mm Russian, 123 grain, USA Full Metal Jacket." (A grain, of course, being 1/7000th of a pound, or 64.8 mg.)
In fact, I do not recall bullet or load (gunpowder) weights ever using units other than grains.
Accuracy in firearms is often measured in minutes of arc, but I guess that arguably qualifies as a "unit in use with SI" http://www.answers.com/topic/minute-of-arc:
"This unit is commonly found in the firearms industry and literature, particularly that concerning high-powered rifles. It is popular because 1 MOA almost exactly subtends one inch at 100 yards, a traditional distance on target ranges."
Jim Elwell
