Chronograph issues

you don't say what chronograph or load you were using but I would guess you have the screens to close to the muzzle and the readings are being affected by muzzle blast

Bfh_auto said:

Caldwell. It was set 15 ft from the muzzle. The load was a starting load of IMR 4064 with a 60 gr Sierra varminter in a 240 Wby. The same rifle with much higher charges of a different powder and a different bullet read correctly. The only thing I could think of was the bullets are a dull color instead of shiny copper. Muzzle blast and recoil was on par with other starting loads.

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Hmmm, that is strange. I wish I had an answer for you, but I don't think it's because of the dull color of your bullets. I mean, talk about dull color - I've shot plenty of swagged lead handgun bullets, and even some dull-colored lead pellets from my pellet guns across my F-1 chrony. It works fine with all of those dull-colored projectiles.

Muzzle blast can cause issues sometimes. Move the sensors a bit farther away.

Make sure the sun is not shining directly on the sensors. I sometimes would tape some index cards to the rods to shade the sensors from the sun.

Also, try using a black marker like a Sharpie to put a black band on the bullet. With small diameter bullets, sometimes there is not enough contrast as the bullet passes over it. I had lots of problems with 17 and 20 caliber bullets and the black band would help.

The sensors may “see” bullets that are closer to them than to the LEDs or shades. But don’t get too close. Chronographs don’t like that.

Maybe the ogive angle caught the sun just right for those bullets? Did they read correctly later in the session? A dull copper bullet may not reflect the darkness of the ground back to the lens on a dull day. Is there snow on the ground in Oklahoma? The snow could be camouflaging it into the sky with a white reflection. A dark tarp may help on dreary days.

sbwaters said:

But don’t get too close. Chronographs don’t like that.

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I shall attest to the durability of the Caldwell Chronograph.

After placing too much focus in the wrong place, trying to get my AR to work with the combination of bags I had with me, I managed to clip the top ear of one. The first shot, that went through the front bag, didn't register on the tablet it was connected to. So I got up and checked all the connection and made sure it was synced. All good. The second round, again, nothing. I thought that maybe I was aiming just a bit high because I could see some of the sun screen in the scope.
So I aimed ever so slightly lower.
This put the barrel to the middle of the front rest's ear. Shot three also did not register. Instead it went through the bag (again), tore open the top of the ear and sent plastic beads every where. I saw most of the bullet strike down to the left of the tripod. And then it began to rain pellets. A piece from the bullet struck the screen. Were it still rattles to this day. It was the second time I had it out. It dodged most of a bullet that day.

I have shoveled the ground free of snow and had the chronograph begin working. Of course then it begins to snow! I have since abandoned trying to do any work ups in the winter. I may have to build one of those dark boxes, but the tripod looks a little flimsy.

Walkalong said:

Sure about that.

And no, I wasn't trying to delete the string.
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I have one of those!
(But mine has a .44mag hole!)

If you can chrony nerf guns....