June 21st, 2014

Texas Technicians Use Accelerometers to Plot Bullet Hits

Waterloo Labs is a group of engineers from National Instruments and other self-declared “nerds” from Austin, Texas. These folks conducted an interesting demonstration using electronic accelerometers to plot bullet impacts from a suppressed Ruger MKIII .22LR pistol. The accelerometers respond to vibrations caused when the bullets hit a drywall target backer. By triangulating data from multiple accelerometers, each shot’s exact point of impact can be plotted with great precision. These point-of-impact coordinates are then fed into a computer and super-imposed into a Flash version of the Half-Life video game (which is projected on the drywall board). The end result is being able to “play” a video game with a real firearm.

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triaxial accelerometerDo-It-Yourself Electronic Target System?
Now, we are NOT particularly interested in shooting Zombies in a video game. However, the technology has interesting potential applications for real shooters. Waterloo Labs has published the computer code, used to triangulate bullet impacts from multiple accelerometers. Potentially, a system like this could be built to provide display and scoring of long-range targets. Sophisticated electronic target systems already exist, but they use proprietary hardware and software, and they are very expensive. The Waterloo Labs experiment shows that shooters with some computer and electronic skills could build their own electronic scoring system, one that can be adapted to a variety of target sizes and materials.

In addition, we imagine this system could be utilized for military and law enforcement training. The walls of structures used for “live-fire” room-clearing exercises could be fitted with accelerometers so the bullet impacts could be plotted and studied. Then, later, the impact plots could be combined with a computer simulation so that trainees could “replay” their live-fire sessions, viewing the actual location of their hits (and misses).

Credit The Firearm Blog for finding this Waterloo Labs project.
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December 2nd, 2012

Aiming Advice for F-Class Shooters

In our Shooters Forum, one newcomer wanted some advice on selecting a reticle for F-Class optics. He wondered about the advantage of Forward Focal Plane (FFP) vs. conventional scopes and also wondered if one type of reticle was better for “holding off” than others.

In responding to this question, Forum regular Monte Milanuk provided an excellent summary of aiming methods used in F-Class. For anyone shooting score targets, Monte’s post is worth reading:

Aiming Methods for F-Class Shootingby Monte Milanuk

600-yard F-Class TargetF-Class is a known-distance event, with targets of known dimensions that have markings (rings) of known sizes. Any ‘holding off’ can be done using the target face itself. Most ‘benefits’ of forward focal plain (FFP) optics are null and void here — they work great on two-way ranges where ‘minute of man’ is the defining criteria — but how many FFP scopes do you know of in the 30-40X magnification range? Very, very few, because what people who buy high-magnification scopes want is something that allows them to hold finer on the target, and see more detail of the target, not something where the reticle covers the same amount of real estate and appears ‘coarser’ in view against the target, while getting almost too fine to see at lower powers.

Whether a person clicks or holds off is largely personal preference. Some people might decline to adjust their scope as long as they can hold off somewhere on the target. Some of that may stem from the unfortunate effect of scopes being mechanical objects which sometimes don’t work entirely as advertised (i.e. one or two clicks being more or less than anticipated). Me personally, if I get outside 1-1.5 MOA from center, I usually correct accordingly. I also shoot on a range where wind corrections are often in revolutions, not clicks or minutes, between shots.

Some shooters do a modified form of ‘chase the spotter’ — i.e. Take a swag at the wind, dial it on, aim center and shoot. Spotter comes up mid-ring 10 at 4 o’clock… so for the next shot aim mid-ring 10 at 10 o’clock and shoot. This should come up a center X (in theory). Adjust process as necessary to take into account for varying wind speeds and direction.

John Sigler F-Class

600-yard F-Class TargetOthers use a plot sheet that is a scaled representation of the target face, complete with a grid overlaid on it that matches the increments of their optics — usually in MOA. Take your Swag at the wind, dial it on, hold center and shoot. Shot comes up a 10 o’clock ‘8’… plot the shot on the sheet, look at the grid and take your corrections from that and dial the scope accordingly. This process should put you in the center (or pretty close), assuming that you didn’t completely ignore the wind in the mean time. Once in the center, hold off and shoot and plot, and if you see a ‘group’ forming (say low right in the 10 ring) either continue to hold high and left or apply the needed corrections to bring your group into the x-ring.

Just holding is generally faster, and allows the shooter to shoot fast and (hopefully) stay ahead of the wind. Plotting is more methodical and may save your bacon if the wind completely changes on you… plotting provides a good reference for dialing back the other way while staying in the middle of the target. — YMMV, Monte

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