I've been pulling my hair a bit lately due to some problems I'm having with my chronograph. The offender is a Pact Model 1 purchased about 8 years ago. I should mention first that I plan to talk to Pact in the A.M. to see if they have any input in the matter. In the mean time, here's what's going on: My chronograph can read .22's but not .45's! Yesterday, I absolutely couldn't get 300 grain .458 bullets from my .450 Marlin to read while at the same time, it gave displays for every round fired from my .22 LR. The 22's were copper plated and the .45's were jacketed hollow points with exposed lead tips. Either one should have had more than enough shadow to get a reading, but the .45's showed ridiculously false readings of about 2000 fps slower than expected. I tried with and without skyscreens and cleaned both the skyscreens and the lenses. Muzzleblast shouldn't have been a big deal as the screens were at 12 feet downrange. Today I even tried marking the exposed .45 bullets with black marker to see if that would help. Still no dice. I will apply any practical suggestions and get back with you all as to what worked.



Thanks



Gabe

1. The screens should be as far out as they can be, in other words the wires fully extended to full length. I run mine at 15 feet.
2. the box shold not be on the same bench you're shooting from. Vibrations from the rifle may scramble the timer at the heart of the chrongraph brain.
3. Make sure the wires from the screens are NOT twisted, but hanging seperated,going directly into the back of the box.

This is what the boys at pact told me when I was having problems with mine.

I have the same PACT & got tired of the unreliabilty of it. I don't know if it's the screens (had them replaced once) or the unit itself. I bought an Oehler & it's just about perfect. You can try Scotch taping over the screen slots (frosty type), it helps a bit.

replace the batteries?

jeffe

Sad to say, that is the nature of chronographs some times.

For sure, call Pact and see what they say. They may be able to shed some light on the problem.

I own an Oehler model 33 and a Pact Professional model. In gneral, they both work just fine. But on some days, they will not read some bullets worth a darn.

My Oehler has a particular problem with Nosler bullets in bright sunlight. I can shoot Sierra, Hornady, Speer, and who knows what other brands but it just will NOT read a Nosler bullet. I called Oehler and they readily admitted to the problem.

My buddy has the same problem with his Pact, though mine reads Nosler bullets just fine.

Just like you tried, Oehler suggested marking the bullets with a black marker. Just like you, I found it to be of no help.

With either brand I find that I get unreliable readings if the sun is low in the sky off to the side of the chronograph. They both seem to work when the sun is high above them.

Check with Pact and see what they say, but sometimes it is just the way it is with chronographs.

R F

I had the same problem with chronys. The factory said I needed a longer cable as I WAS MOMITORING GAS. Interestingly was the fact that all of my rifles with recoil compensators could be read just fine. All the gas from these recoil comped rifles( or a larger quantity of it)was not going over the sensors. Chrony said I had to supply my own cable. I supplied myself with a new three screen Oehler. I gave away my two remaining chronys and shot the third. roger

Griz pegged it.

As I was typing the initial post I was going over the differences in my setup between the .22 and the .45. It occured to me that while I was trying to get the screens as far away from the blast as possible, in doing so I had inadvertantly placed the unit slightly in front of the muzzle and off to the side by about three feet. In other words, it was in the worst possible position for taking a beating from the muzzle blast.

Griz posted the same thought the next morning. I promptly headed to the range, made the adjustments, and all is well now. Thanks to all who posted.

Gabe