Quartz Lok Chronograph.
The two light-emitting slots are located on the top surface of the box. Spaced exactly 12 inches apart, the slots are 1.03 inches wide, and I assume they cover a fan-shaped area above the chronograph. On the top rear of the box is a horizontal slot into which you slip a special heavy cardboard reference target. This target, which has a 2-inch diameter hole in it near the top, measures 4-1/2 inches and 7-1/2 inches high. When in place, the center of the aiming hole is 4-3/4 inches above the top of the chronograph. As long as your bullet passes through this hole, its velocity will be measured. The bullet can pass below the hole and still trip the screens, but if you shoot above the hole you may miss the field covered by the screens.
The front face of the Quartz Lok 77 is and LCD crystal which displays large black numbers against a silver-gray background. On the back of the unit is an on/off switch and the thumbscrew. Removal of the screw drops the back plate, beneath which is located the power source for the unit--a single 9 volt alkaline battery.
Setup and use of the Quartz Lok Model 77 is simple. There are no wires or screens to bother with. Simply attach the chronograph to a camera tripod via the threaded hole in the bottom of the chronograph. Position the chronograph at least 10 feet from the muzzle of your rifle or pistol and adjust the tripod so that the box is level with your line of sight and so that you can shoot through the 2-inch hole in the reference target. Then, turn the chronograph on and start shooting. the camera tripod isn't a necessity--you can sit the instrument on a box, rock or whatever--but a tripod is most convenient and allows for perfect alignment with your line of sight.
Readout of the velocity is direct in feet per second (fps). This appears on the screen a couple of seconds after the bullet passes. The velocity is displayed on the screen for approximately 8 seconds, after which the four zeros again reappear. This gives you plenty of time to record the reading. Another shot should not be fired until after the display returns to zero. There are provisions for signaling an error as well as a weak battery indicator.
I had some reservations about the accuracy of a chronograph with only a 12-inch screen spacing, but these were quickly dispelled when I fired a variety of ammunition across the Quartz Lok 77 and compared these readings with those gathered with my Oehler M33 and Skyscreen II system. The results of this comparison are shown in the accompanying table. as you can see, the velocities I checked covered everything from just over 1,000 fps to almost 3,000 fps. Velocities recorded with the Quartz Lok 77 were surprisingly similar to those of the Oehler. Four of the five loads were within one percent; one showed a difference of two percent.
The only problem I encountered with the Quartz Lok was its inability to "read" jacketed bullets fired over it when the sky was blue and the sun bright. Having encountered this problem with other chronographs, I knew the solution. Using a black felt-tip pen, I blacked the bullets of the ammo to be chronographed. Presto--no more failures.
Operation of the Quartz Lok Model 77 was perfect and the accuracy unquestionable. I think the instrument has tremendous application for the average handloader. It'll also be great for measuring downrange velocities--as long as you're sure of the accuracy of your rifle.
Retailing for $230, the Quartz Lok MOdel 77 is available from Gary Sepp, Distributor, Dept. GA, 13137 N. 21st Lane, Phoenix, Arizona 85029. Add $5 to your order for postage and handling.
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|Publication:||Guns & Ammo|
|Date:||Sep 1, 1984|
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