Caldwell Ballistic Precision Chronograph 1006315-SSI

Product Information

These items normally require Identification (Passport) or a Firearms / Shotgun Certificate before they are handed over. Shotguns, Rifles, Airguns and Moderators are usually good examples. When purchasing a 'collection only' item you are in effect paying a deposit for your goods. In all instances you can choose to collect your item from one of our stores (Exeter, Dorset or Newport) or from a 3rd party gun dealer. The latter may be at an additional cost to yourself. The Caldwell Precision Ballistic Chronograph provides accurate velocity measurements across a wide range of shooting conditions. Higher accuracy was achieved by using a high speed 48 MHz processor and by designing a circuit with an advanced data interface that allows each unit to be computer calibrated at the factory after assembly. The end result is the ability to provide much better accuracy than other chronographs on the market (+/- .25%). Then the circuits are changed so that the electricity comes to each magnet through a wire screen. The rods are re-hung on the electromagnets. Now that is not the actual accuracy of this chronograph. If this microcontroller could detect an object at any instruction cycle, it would have an accuracy of 99.9925% at 300fps because its worst case scenario of not detecting an object when it has broken the beam could only be 83.3333ns before it would actually detect it.

If a paintball is traveling at 300fps, it takes 3.3333ms to travel 1ft (1 / 300fps = 3.3333ms). Seeing as our IR Transmitter/Detector pairs are spaced 4" apart, we have to divide 3.3333ms by 3 (1ft / 4in. = 3). So the time it will take the paintball to travel 4" at 300fps is 1.1111ms. Custom Carry Case Designed to store and transport Chronograph, Sunshades, Light Kit and Tripod Constructed of Durable Ballistic Fabric Heavy Duty dual zipper design After all the holes are drilled, the two IR transmitters are placed in their respective holes. Seeing as we used a 3/16" drill bit, the holes diameter is only ~4.8mm. This means that the 5mm LED will not completely fit in the hole, this is what we want though. We just want the IR LED's to slightly poke into the barrel, for two reasons. First, it helps direct the IR beam in a straighter path to the IR detector. Second, it reduces the chance of a projectile striking the IR LED itself and damaging it. Now that we got all of the requirements and setup out of the way, we can move on and finally get to the exciting stuff. The operation of this chronograph is rather simple, there are two IR transmitters and two IR Detectors, each transmitter/detector pair is placed exactly four inches apart. So assuming that there are no other sources of error (distance is exactly 4", beams are broken identically on each side, etc) we would have an accuracy of 99.865% at 300fps for this chronograph. This is very good, however, there are many other small sources of error that I have not accounted for. Therefore it is highly unlikely that the chronograph that I build or you build will be 99.865% accurate. Nonetheless, it works quite well and I am very pleased with it.After you have drilled the two holes for the IR transmitters, put the drill in the second hole you drilled and make sure it is completely perpendicular to the PVC pipe (there is pictures for most of these steps). Drill through the other side of the PVC pipe. You have just drilled out the hole for the second IR detector. Next, flip the pipe over and measure 4" across the pipe from the exact center of the second IR detectors hole. Make a mark and drill another hole, this one is for the first IR detector. Say we fired a paintball through the chronograph. Once the paintball has traveled through the chronograph and broke beam #2, we go and read the value of TMR1H:TMR1L (it's a 16-Bit value). For examples sake, we'll say the value we read was 15,930. Here is how we calculate the velocity of the paintball:

As mentioned in the intro, this chronograph also has a Rate of Fire (RoF) mode. This allows the user to determine how many shots per second their paintball marker is capable of. It is pretty straightforward, when switch #2 (S2) is pressed, the chronograph switches from velocity mode to RoF mode and vice versa. We know that the distance between the IR "beams" is exactly 4 inches. So all we need now is to know how long it took the projectile to travel from beam #1 to beam #2. This is what Timer1 is used for. Every instruction cycle (83.3333 ns) the value of TMR1H:TMR1L will increment.The reason I don't drill through both IR transmitter holes and instead I measure 4" from the second IR detector hole is for accuracy. It is to ensure that both IR transmitters and both IR detectors are spaced exactly 4" apart from each other. This minimizes the error in the calculations and allows for greater accuracy. Now we'll take a look at what calculations are needed to get the actual velocity of the projectile. The True Ballistic Radar Chronograph measures actual speeds at four different velocities readings from 0 - 300yrds to determine actual ballistic coefficient using G1/G7 drag models. This provides actual data in your conditions, info that provides the difference between a hit and a miss. Whats it worth to you to hit your target? Use the on board display or connect to the FX Radar app to get more out of the ballistic data. Features All in all, I am quite pleased with how the chronograph works. It wasn't very difficult to build and the code itself is pretty easy to follow. Eventually I plan to update the code and use INT0 and INT1 to detect when a projectile is being shot through the chronograph. This will increase the accuracy and allow for much more efficient code. I would like to make a smaller version of this chronograph, but it is pretty tough to make a lot smaller due to the 16x2 LCD Display. Perhaps I will look into using 7-Segment Displays as a means of relaying the data to the user. Please note that your goods may be sent to you in instalments as availability of products can vary. For example certain products have specific delivery requirements which are explained below.