Chrono No-Nos: Remember this Device is a Tool, Not a Target
“Shooting Chrony” is a product name. “Shooting Chrony” should not describe (post-mortem) what you have been doing to your chronograph. Sooner or later all of us may make a mistake, and ventilate our chronograph. With luck, the bullet just “wings” your chronograph, and the damage is minor. But if you hit the unit smack dab in the middle, you may have to retire your chrono for good.
A while back, Forum member Jeff M. (aka “JRM850″) experienced a “low blow” that put his Shooting Chrony out of commission. With tongue firmly in cheek, Jeff started a Forum thread entitled Chronograph Not Picking Up Shots in Bright Sunlight Anymore. Looking at the photo at top, the problem is obvious — he ventilated his Chrono.
This was Jeff’s first chrono kill in 23 years of use, so we shouldn’t be too critical. Jeff explained: “I didn’t realize a friend was shifting from a 300-yard target to 100 yards.” The agent of destruction was a low-traveling 58gr V-Max running at 3415 fps. What happened? Well, when one is shooting at 300 yards, the trajectory will be higher than at 100 yards. We should say, however, that this may have been a low shot, or the 100-yard aiming point may have been placed lower to the ground (closer to the bottom of the target frame), as compared to the 300-yard aiming point.
Other Forum members offered some sarcastic responses:
Try it on an overcast day – it might work again.
It looks like the V-Max performed just about as advertised.
Aww…a little duct tape and some Super Glue and you’re good to go.
Double Check Your Aim Point and Trajectory BEFORE You Shoot
The lesson learned here is that you should never change targets (or aim points) without checking your bullet’s flight over the chronograph. We like to align the barrel so the bullet exits a good 6-8 inches above the electronics (check your manual for recommended shot height). In addition, we always boresight the barrel so we can see the actual target through the bore. Then, with gun UNLOADED, bolt removed and action clear, we look back down the barrel so we can see daylight through the bore, with the gun set on solid rests. If you look through the middle of the “V” formed by the sky screen supports and you can’t see light shining through the barrel’s bore, you probably have a set-up problem and you should re-align the rifle.
Use a Test Backer to Confirm Your Bullet Trajectory
You can put tape on the support rods about 6″ up from the unit. This helps you judge the correct vertical height when setting up your rifle on the bags. Another trick is to hang a sheet of paper from the rear skyscreen and then use a laser boresighter to shine a dot on the paper (with the gun planted steady front and rear). This should give you a good idea (within an inch or so) of the bullet’s actual flight path through the “V” over the light sensors. Of course, when using a laser, never look directly at the laser! Instead shine the laser away from you and see where it appears on the paper.
After you have used the laser boresighter to get the rifle centered up in the chrono’s “sweet spot”, confirm with a test shot or two (see photo). Even when using an in-chamber laser boresighter, it is not uncommon for the bullet’s actual point of impact to be different than the laser’s dot location.
Similar Posts:
- How NOT to Ventilate Your Costly Chronograph — Set-UP Tips
- Embarrassing Moments: Shooting Chrony Bites the Dust
- Don’t Kill the Chrono! Setting up Chronos to Avoid Stray Shots
- How NOT to Ventilate Your Chronograph — Set-Up Tips
- Range Tip: How to Avoid Blasting Your Chronograph
Share the post "Chrono No-Nos: Remember this Device is a Tool, Not a Target"
Tags: Chronograph, Laser Boresight, Shooting Chrony, Skyscreen
You ought to see one with a 20″ crossbow bolt stuck through it. Talk about penetration.
In all defence I used my first one for several years before shooting it.
Anything placed down range is subject to collecting holes.
I wonder if the internal electronics can be damaged slightly by shooting the steel housing? as i have done.
Many moons ago, when PACT first came out with a semi-affordable chronograph, my father purchased one with the hopes of leveraging the data to make better handloads…mostly for verifying major pistol loads. The PACT gave us fits, and only seemed to work occasionally…when it wanted to, once in awhile.
I still remember vividly sitting at a cold concrete bench in early spring as we tried over and over again to chronograph some .223 loads for dad’s AR15 and some 25-06 loads for the upcoming Ohio groundhog season, and the chronograph, as usual, did not always give a reading…
Those were pre-internet days, with nobody but the manufacturer’s help line to call for help, and quality service was not available 24/7.
We were focused on getting good readings, and thought that maybe the bullets were not close enough to the sensor. Dad was crouched behind me, instructing me to shoot carefully lower and lower over the PACT. At some point I remember telling him that I didn’t think I could shoot any lower without destroying it…but still, we could not get a consistent reading and we finally gave up.
When packing it away, we had to laugh at the plastic sensor housings…there were a bunch of half circle marks melted into the very top. It took about a minute for us to realize that we had actually shot so low that the bullets were skipping off the top of the plastic housing…you seriously could not shoot any lower…and we laughed at how unreliable technology could be, and we packed up the PACT and never shot over it together again.
After my dad passed, that POS PACT came into my possession and sat in a box for a couple years. When work moved me to California and I finally setting down enough to reload again, I pulled that testy device out one last time to see if I could figure out how to get it to read one last time before I tossed it.
In the harsh California sun, with no clouds in the sky, that PACT worked just fine…every time. After time, I noticed that should a cloud happen to pass overhead, or the shade move over the PACT, it would quit working. The overcast sky so common in Ohio was the PACT nemesis, something you’d think the manufacturer would have been able to help us figure out many years prior.
I still use that same PACT chronograph a couple times a year to help me verify a new lot of powder and to assist in building new drop charts. It still cracks me up seeing the melted bullet marks over the sensor, and I think how much time my dad and I spent fiddling with it in Ohio. When the electronics finally give out on this luxury tool, I can promise you that I’ll bring my 25-06 out with a Partition load, and ventilate it properly…then go home and drink a scotch in honor of my dad.
Retire it? Bury it I’d say…
I know that Sierra does not recommend that shooters use Matchkings for hunting, but I must admit that a 190gr MK out of a 308 made a quick and clean kill on my Chrony a few years back.
Why would anyone concern themselves with range when shooting over a chronograph? The whole point is to measure bullet velocity not too far from the muzzle, not see how accurate you can be at different ranges.
When I was working up match loads, I didn’t care about anything except the consistency of velocity. So long as the bullet passed through the screens and safely hit the backstop, nothing else mattered.
I like the PACT style system where only the inexpensively replaceable skyscreen sensors are exposed to wandering bullets.
My original first generation PACT had it’s share of non, or funky readings due mostly to light changes while shooting. I’m ordering a new one with the infrared skycreens.
I learned the hard way when I helped my nephew site in his slug shotgun. It seems that the wad will inflict quite a large amount of damage by itself. Lesson leaned!
Patrick Kelly