A real headscratcher with Chronograph

[amlevin]

The other day I was chronographing some loads that really did well for accuracy. Two bullet weights, a 73 gr. Berger and a 52 gr SMK.
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The 73's registered nice clear speeds on my Pact chrono with the I/R screens. When I switched to the 52 gr bullets the chrono stopped registering, period. Went back to the 73's and good to go, again.

Tried several different "paths" across the sensors with the 52's but only got two shots out of 20 to register.

Any ideas? Are the 52 gr SMK's just too small unless the conditions are just right? Anyone else have this happen.

Most of my use for this chrono has been .308 rounds and no issues, just the 'teenie weenie" ones

 

[lrgoodger]

The smaller they are, the more trouble the light sensor has seeing them. I used to have trouble getting readings on the little 40 grain v-max on sunny days, but I don't shoot them any more.

 

[Backwoods Blacksmith]

Try using a heavy tip black magic marker. put a thick line on the bullet, tip to case. This should allow the pick ups to see the bullet better. Also keep out of the bright sun.
Hope this helps

 

[MQ1]

Funny, my PACT will only work in bright sun....

MQ1

 

[jghoghunter]

My pact was one of the first ones to come out in the early 90's and it only read about half of what I shot over it. Tried just about everything you could think of to make it work it finally, last year meet its demise with the hammer. I went and bought a cheap chrony haven't had any issues since.

 

[amlevin]

My pact was one of the first ones to come out in the early 90's and it only read about half of what I shot over it. Tried just about everything you could think of to make it work it finally, last year meet its demise with the hammer. I went and bought a cheap chrony haven't had any issues since.

I think I might just lower my aim. More fun than a hammer.

What's really puzzling me with this is that our range has huge baffles over the area that the chrono has to sit so it's usually in the shade. I purchase this unit with the infra-red screens to overcome the light issues. I'll try the "marker" method and see if that makes any difference.

Wish someone nearby had a "Rental Service" for magneto speed chrono's. Don't need it for the big bullets but I could then just rent one for the few times I shoot the tiny ones.

 

[fredhorace77]

here's my experiences. more often than not my problems have been due to having the chrono too close to the muzzle, make sure the so called lense is clean, and u can try different materials for the sky screens. my standard pact chrono picks up the difference in light when the bullet passes by. too much direct sunlight will over power the lens capability of seeing and too little light dosent cast enough shadow on the bullet. more often than not shooting higher is better than lower for me. my manual says bullet should pass 6" above the eye for optimum readings ...i measured 7.5 inches above the eye and put some masking tape on the side screens. when i set up chrono i turn my scope on lowest power setting and put my cross hairs level with the tape. if my scope is appox. 1.5" above the bore then the bullet should pass at about 6"

 

[vtmarmot]

I was having trouble with my Shooting Crony at my usual range due to the position of the bench roof. I could only get a reading when the sun was just right. I then bought their LED screens and battery. This cured most of the problems, even on a day when storms were moving through. It was a good purchase.