Clocking reloads

M

Micro man

New member
Got a Caldwell chronograph recently and have been having issues using it.
In a limited number of shooting sessions I have managed to shoot the metal rods holding the sun shades twice. I have probably shot 20-25 rounds through it and managed only 3 or 4 velocity readings. I stand about 10 yards from the chronograph when shooting and frequently get error (2) “ bullet not detected “
I have only tested it with 2 revolvers, both snub noses. I was under the impression that any shot between the metal rods would be detected but that does not appear to be the case.

Any help would be appreciated.
 
It's too far away. I place my chrono at about 8-10 feet from the muzzle. And I shoot supported from a bench to prevent a wobbly, flinchy hold that could result in shooting the machine or its metal rods.

I haven't used that brand but in general the bullet needs to pass over the center of the sensors. Even a minor deviation can result in a failed reading.
 
I use my chronograph (a discontinued Shooting Chrony Beta) anywhere from 6" (certain .22 rimfires) to about 15 feet from the muzzle (big boomers, or difficult terrain).
Anything more is harder to work with, and the data is less useful.

Try to put the bullet right down the middle, with the chronograph level with the plane in which the bullet is traveling.
If you're shooting the rods, you're way too wild; and/or too close to the sensor.
Put the bullet about 4-6" above the sensors, right down the middle.
Should work in any light conditions.
 
Definitely should place the screens at 15 feet. I settled on 15 because my 7mmRM blew the screens down at 10 feet. I bought an Oehler 33 in the 70s and recently replaced it with a 35P to print my strings.
 
I have shot with many chronographs before. I always used a rest. That is key. Mine was a Shooting Chrony. It was about 10 ft away from the muzzle. I tried to get it right down the middle and sights about even with the rod joints. Never shot a rod. I found the screens were needed in the sun, but not with clouds.

Good luck.

Lots of used Labradars for cheap lately…much easier to use.
 
There was a question about if I was shooting inside or outside -all my shooting was outside. Isn’t the Garmin chronograph about $600, it looks great but too rich for me.
 
One thing that helps me with chrono work is that when I'm doing chrono work, that's ALL I'm doing.

I'm not trying to hit a target or shoot a group; the only things I'm doing are making sure the round goes right down the middle of the sensors and insuring that it's not too high or too low.

That approach lets me get good results from a cheap chrono. If you can't stand to spend money burning ammo solely to get velocity results, then you will have to spend your money on a really nice chronograph instead. Or live with the kind of results you've been getting.
 
With a budget camera tripod, I managed to do both.

Chrono has 2 photoelectric sensors exactly 12” apart. They detect the bullet's shadow when it passes over. Lighting is the key to produce the shadow. Not too bright and not too dim. Even a overcast sky on an outdoor range can cause problem.

My always-work solution is LED tea lights velcroed to the underside of sun screen to shine light right over the sensors.

After shooting 3 chronos in 5 years, I finally got a labradar. Much better.

-TL

Sent from my SM-N960U using Tapatalk
 
I replaced the metal rods with wood dowels and put red tape on them about 1/2 way up. This helps me aim at the right height. I adjust the tripod to keep the chronograph parallel to the bullet. As often as I want to clock reloads this works for me. I don't use it enough to justify $600 for a Garmin.
 
having had and used two competition electronics "procron digital" chronos i find that using the shades is not always needed, and that you want to avoid direct sun light, i generally set the speed clock at exactly 15 feet from muzzle, on a few occasions, i have had to use black marker on the bullets to get them to be seen. but generally have good results.

it's already been mentioned keep things as straight as possible, and not too far from the muzzle.
 
The SAAMI standard chronograph protocol calls for the middle point between the screens to be at 15 feet (5 yards). If you want to compare your velocities with commercial ammunition or published load data, that is the distance a domestic company will have used. They will usually have used a SAAMI test barrel of a specific length, so if your barrel length is different, you will have to allow for that.

You can do a coarse calibration check with 22 Match ammunition in a rifle with a barrel at least 18" long. 22 LR burns all its powder up in a rifle barrel, and in a longer barrel, it doesn't lose much velocity after that burn-up point. As a result, most 22 LR rifles will fire match ammunition to within ±50 fps of the velocity published on the box. If you run this test and get a bigger difference than that, you are likely having a chronograph issue. For optical chronographs, 99% of the time, this is due to light conditions (see next paragraph).

The best way I've found to work with an optical chronograph is to buy their IR light source kit, run it off batteries (or with an inverter on a motorcycle battery if it needs AC power), and shade the instrument from natural light. The Oehler does well with natural light, but even it can have issues in extreme enough light conditions. I notice Caldwell now sells a more expensive unit that operates off IR by inverting it so it gathers light from below. You could adapt the lower price unit to do that, as long as you are willing to read the display upside down.

I have set my two optical units (Oehler 35P and CED Millenium) up at as much as 100 yards to measure velocity loss in rifle bullets. As long as it is far enough from the gun to avoid muzzle blast effects, it should measure the bullet going over it. In the case of the long distance, though, the rifle needs to be tested to hit the middle of the bull behind the middle of the screens, and the grouping should be small enough not to be likely to damage the unit.

Other optical chronograph tricks include:

Making a black tunnel to set the chronograph up in with its IR screens. This really kills all outside light interference pretty positively.

Laying some black material or plastic under the tripod to prevent light glints and reflections from the ground. This usually is unnecessary on grass, but if you have a bare dirt, sand, or gravel range, false triggering from ground-reflected light can be an issue.

If you are shooting off a rest, set the cleared gun (bolt out of a rifle, cylinder open and empty on a revolver, slide or bolt open and empty chamber indicator in place on self-loaders) up on the rest so it is aiming at the target. Pul a laser bore sighter into it and turn it on. Go out to the chrono and shift and angle it until the beam passes through the middle of the sensing areas. Put your palm in the middle of each screen area to see the beam location.​
 
Very comprehensive explanation Unclenick as always. I have some time off next week and intend to incorporate a number of the members suggestions and hope to have a more productive shooting session this time around.
 
I replaced the original set of uprights with two pieces of 1/16" SS heliarc wire bent to fit. Makes a smaller target.

On the front wire, I added a 4" florescent orange zip tie to each side. Setting them 6 - 7" above the sensors gives me a point to set up the rifle on the rest, and then adjust the chronograph to the horizontal bar in the reticle.

If I am having issues with the chronograph picking up the bullets, I take one of the manilla colored targets, fold the outside edges and use clothes pins to attach it to the wire frames.

I have two of these units. When I set up a new bow or change arrows, I use them both to get velocities at the bow and the target. This let's me choose the best set up for weight and speed.

So far, I've managed going on 20yrs without hitting the main unit. I did hit and break the original plastic diffusers with an arrow at 30yds, but that just made me come up with the heliarc wire fix, and it has been far easier to use.
 
Am not experienced with the caldwell, but years with a chrony. The sun shades provided were problematic, especially with low angle sun light. Larger shades got wind affected. Eventually just used small vertical pieces of card board right at the sensors to block angled light. Really improved the capability to get readings.
 
I have a Caldwell that I have zero issues with. I usually set it up about 10' or so out, but shooting BP I've found that particulates cause error if I don't set it closer to 10 yards or further :eek: or so. That gets a bit nerve wrecking shooting C&B revolvers, especially open top colts that shoot naturally high (I'm literally aiming an inch or two over the body of the chrono). I bench rifles, shoot handguns standing like I always do. I always shoot at a target, and I position the myself/chrono/target so that the bullseye is dead center of the chrono window and the chrono is perfectly in line. I do not shoot for groups, I just shoot to hit the center of the target. Never had any issues. My chrono has the led light kit that runs off batteries. That helps on certain days, but it's usually not needed.
 
First sit down and use a rest; secondly, my chrono works best at 5' from the muzzle (per their instructiins) for both handgun and shotgun
 
You must log in or register to reply here.
Back
Top