Does your CED M2 not work well?

[Keith Glasscock]

I recently bought a CED M2 chronograph. The first time out (in August) it worked really well except when the light changed. As a matter of fact, slight changes in lighting (like the difusion from a whisp-thin cloud over the sun) would change the velocity 50 fps.

As the weather worsened this fall, I was unable to get any readings at all. I assumed that it was poor lighting and decided to save my pennies and get the IR skyscreens.

Well the IR units arrive last week and the results were less than satisfactory. Know loads with good ES and SD (measured on other chronos) were indicating as much as 200 fps below the "known" velocity in 223Rem. 308 diameter bullets faired better, but the velocity was still low and gave me ES's as high as 80 fps. While all of this was going on, a friend of mine was using an M2 with the normal skyscreens and getting excellent results....

Before calling CED, I decided to take a look at the sensors and see if there was anything obvious (like dust on the actual light sensors). To my surprise, the answer was right there...

The CED sensor uses a lens to push the sensed light into a narrow beam on the light sensor. One of my units was missing that lens. A quick call to CED (I spoke to Kim, a very nice lady) got me the address for a repair. With the 2012 F-class season looming, I'm hoping that they can get it back to me on my timeline so I can finish my new load development.

If anyone out there has a CED that doesn't work right, please don't give up on it, but do look down through the slots in the sensors and make sure the lenses are in place. It may well be worth your time to give CED a call.

 

[RDavies]

Thanks for the heads up. Myself and some others are having issues at the moment. I,m pretty sure I had a look previously, but didnt see anything.
(but then I just had a daddy look, not a mummy look)

 

[JJH]

I will have to take gander at mine. I recently picked one up, two range sessions with the exact same load I was seeing a 250fps difference. Not real helpful data getting readings that far off.

 

[Keith Glasscock]

The lens that I had in one sensor was a rectangular piece about 3/4" long and 1/4" wide. When I looked at it with a flashlight, it turned the flashlight beam into a rather higher intensity line across the sensor. I did notice that the lens directed the light that wasn't coming from directly above away from the sensor. From an accuracy standpoint, that would make sense to me. The sensor should only see light from the vertical plane above it.

 

[lrgoodger]

Good to know stuff! There's something else to check, too. While looking to see if my lenses were in place (I had been having trouble recently), I noticed that there was a lot of dust on them. I didn't realize just how MUCH dust until I cleaned the lenses with a Q-tip. I expect it will work like new again now.