A couple announcements: I’ll be out of town until Wednesday, May 24. My daily blogs will be posted automatically. I won’t be able to answer questions, so I’d appreciate it if other readers could step up to the plate and help out.
Tom Gaylord has posted an article about PCP hand pumps that also includes a short video. If you are unable to view the video or cannot download Quicktime, please post your comment to this blog. We’re assuming everyone can watch the video unless you tell us otherwise.
Now, on to today’s blog!
by B.B. Pelletier
Here is a device many of you need – the Alpha model Shooting Chrony chronograph! Pyramyd Air sells both the Alpha and the Beta models, and the only difference is that the Beta has a larger memory for storing longer strings of data, plus it holds the data when turned off. Let me explain.
The Alpha Chrony is shown with the diffusers installed.
What IS a chronograph?
A chronograph is a device that determines the velocity of projectiles such as bullets, pellets and arrows. Modern chronographs use light sensors to start and stop a high-speed counter. Using the distance between the start and stop sensors (skyscreens), the chronograph calculates how fast a projectile is traveling by determining how long it takes to go from the first sensor to the second.
What the Alpha Chrony gives you
The Alpha Chrony is a self-contained unit housed inside a metal box. Just unfold it, switch it on and start firing! If you follow the directions, the Alpha model (and the Beta model) give you velocities accurate to more than 99.5 percent. Typically, the Chrony will be less than 10 f.p.s. off at a velocity of 2,000 f.p.s. The maximum error is less as velocities decrease, so this is perfect for airgun use! Velocity reads out within seconds on a screen on the front of the unit. You can also push a button to get information like the total number of shots in a string (up to 32 with the Alpha), fastest shot, slowest shot, extreme spread, average and standard deviation.
This was taken during the Benjamin Legacy test.
The unit runs on one 9-volt alkaline battery (not included). It MUST be an alkaline battery for the electronics to work properly. The battery lasts a long time, although you should turn off the power if you’re not going to be shooting for a while. The Chrony can sit flat on a table, or it can be attached to a camera tripod. The tripod is probably the better way to mount it because you can angle it down to shoot into the ground. You can leave it on the tripod for transport, too.
The sensors are called skyscreens because the normal way to use them is to point them up toward the sky. If the day is completely clear or overcast, this works well, but a bright sun or fast-moving clouds requires the use of a diffuser that comes with the chronograph. The sensors require the pellet to pass over the center of the chronograph at a height of 4″ to 6″. This is not too hard to master. If you have difficulty knowing which way the barrel is pointing, you’d better erect the diffuser stands as a guide. The most common mistake is pointing the barrel down. You’ll eventually hit the top of the second skyscreen this way.
You can use lights instead of the sky, but they have to be incandescent bulbs. Almost every other kind of light bulb will either trigger the sensors or give you no reading at all.
Why is the Chrony so cheap?
The Chrony is a careful blend of the features and attributes you need – with the elimination of everything else. Other chronographs have faster counters, so their error is smaller than 10 f.p.s. for a 2,000 f.p.s. bullet. Some have additional sensors to give you a check channel – which acts as a second chronograph. Some have printers (Chrony offers this as an option). But like I said, you don’t need all that. For getting started with a chronograph, the Chrony is the best and least expensive way to go.