by Adam Heggenstaller - Friday, April 11, 2014
If you're a handloader or a hunter who wants to determine the true muzzle velocity of a particular load from a particular gun, you need a chronograph. There are several portable models on the market, but Managing Editor Chip Lohman of Shooting Sports USA may have just discovered the easiest one to use. Check out his report:
Here at NRA, we’re fortunate to have a dedicated test range outfitted with a permanent Oehler Model 36 chronograph. On the occasion when we need to cart a portable chrony into the field, we do it the same way as everyone else: Set up the screens, deal with a wobbly tripod, hope the light is adequate and try not to shoot the rig.
The folks at MagnetoSpeed in Austin, Texas, have built a better mousetrap. As shown above, there are no screens, tripods or even light required because the unit measures magnetic pulses rather than shadows cast with lights. The MagnetoSpeed chrony's sensor hangs in front of the muzzle, and naturally my first question was, “How do I avoid shooting it?” That was easily solved with the included 1/4-inch alignment rod and spacers that ensure proper clearances.
Thanks to an intuitive design, there’s not much of a learning curve with the MagnetoSpeed chronograph. The display has been logically programmed to list high and low velocities, along with mean, extreme spread and deviation values. The battery-powered display runs for 30-100 hours depending on use of the backlight. The archived results can be reviewed on the display or transported to a laptop with the included microSD card. After a review of the one-page quick-start guide, I was able to toggle between easy-to-understand screens that automatically “wake-up” when the retractable data cable is inserted.
This technology requires choosing a bullet type and density. MagnetoSpeed makes this easy by using plain-English descriptions such as the default setting of “Copper+Lead (.223-.458 CAL.)” or “.22/Shot/Slug (Lead or Thin Copper Plating).” I tested the MagnetoSpeed concurrently with our Oehler chronograph while shooting Atlanta Arms & Ammo match .223 Rem. loads with 77-grain Sierra bullets from a National Match Armalite M15A2, and the results were very close. The MagnetoSpeed consistently clocked the Sierra boattail at an average of 24.3 fps faster, which makes sense since the measurements are taken right at the muzzle instead of 15 feet downrange as with the Oehler.
The current configuration won’t work with a bow or semi-auto pistols that tip the barrel each cycle. Otherwise, the V2 model (the V1 was released in 2011) worked flawlessly. The new V3 model was just announced and includes an improved, smaller display with a 9-volt or two CR123 batteries instead of four AAAs. It also features updatable firmware, a rapid-fire mode and enhanced operation for airguns and shotguns. MSRP is $399, and it will soon be available through Brownells, MidwayUSA and others. All units come with a two-year warranty; those purchased directly from MagnetoSpeed also carry a 30-day money-back guarantee. Watch for a $200 Sporter model (smaller, simpler display) this summer.
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