Outlier fps On Chronograph?

[LanceS4803]

What caused the weird outlier chrono reading?
Working on a new load with BH209 today (110gr bV, 85gr bW, with 250gr Hornady SST and black Harvester sabot). Got the following chrono readings:
2066
2056
2053
*2125
2065
2054
2052
2037
In the end, leaving that one out only changed my average by 7 fps, but any idea what could cause this?

 

[MrTom]

That's interesting. Assuming you weighed all of the charges and no chance a little extra got dribbled in on one of them?

 

[LHR]

What chronograph are you using?

 

[LanceS4803]

Each charge weighted to the 10th gr.
An older Chrony F-1. (Moved out to 20' for the MZ.)
Maybe I am just looking for an excuse for a new one?

 

[LHR]

Each charge weighted to the 10th gr.
An older Chrony F-1. (Moved out to 20' for the MZ.)
Maybe I am just looking for an excuse for a new one?

Your within the margin of error for that chrony F1, I know mine got so aggravating I nearly shot it on purpose many times!
If your shooting in low angle sunlight, error's and erratic readings were normal, partly cloudy days were particularly bad.

 

[LanceS4803]

Anyone have suggestions for a new one, reasonably priced. Would like the LabRadar, but...

 

[LHR]

Competition Electronics Pro Chrono is what I have now, its not perfect either and have some of the same lighting issues. But for just over a $100 it works pretty well. I too would love a LabRadar and will some day, but for now this one will do. I should add it is far better than my old F1.

 

[sabotloader]

Lance, I am not sure I would purchase another one quite yet. Think I would change the batteries and do a couple of additional test to see if it drops the ball again.

 

[LanceS4803]

I'll give it another go.
But first, off to Utah for pronghorn!

 

[sonny from st. louis]

I do not know your desired accuracy requirements. I have used an Oehler 35P since 1987 with no problems. Proper setup requires some time but worth it in the long run. When I say proper setup means to shoot straight through the screens both horizontally and vertically. I have seen shooters shoot through at an angle which gives a bad velocity reading. The chronograph has program switches to set the parameters. One of them is the screen distance. I normally use 4 foot spacing. The chronograph will use this calculation. If you go through at an angle, the distance can be increased from 48" to approximately 52". I measured this in my shop by measuring at an angle in both horizontal and vertical angles. The way I see it when I use expensive ammo, I want the best readings for calculations. I can show my setup for the Oehler 35P chronograph if you want.

 

[RobRed]

Did that shot group with the others or was it a flyer?

 

[sonny from st. louis]

According to Oehler Research, the screens can be tripped from the base of the bullet rather than the point. This is why the Oehler chronograph has a proof screen and two oscillators for time measure. Dr. Oehler has worked out a system of time to detect this. If you are interested, see the Oehler web site. Every time I had an error, it was in setup. Dr. Oehler did a good job on this

 

[sonny from st. louis]

The Oehler people says the hardest bullet to measure is a small, shiny, and fast bullet (17 caliber jacketed bullet in a rifle). The easiest bullet is a large, dark, and slow bullet (45 caliber lead bullet in a revolver). I believe they are right from my experience.

 

[LHR]

I'll give it another go.
But first, off to Utah for pronghorn!

What unit? My sons speed goat hunt starts Saturday out here too? If your driving you could bring your muzzle loader with you and use my chronograph.

 

[sonny from st. louis]

I will mention one other thing that give me trouble. I had to set my start screen at 14 feet from the muzzle. I had debris coming from the gun barrel that would trip the start screen causing an error. I went to Oehler Research and they recommended a distance of 14 feet from the muzzle.

 

[LanceS4803]

What unit? My sons speed goat hunt starts Saturday out here too? If your driving you could bring your muzzle loader with you and use my chronograph.

Puddle Valley. There are 2 NR hunters for that unit.

 

[snapbang]

Is there a chance the sabot got ahead of the bullet?? Doesnt seem like it but weird things happen.

 

[HC]

Maybe a light bullet?

 

[LHR]

Puddle Valley. There are 2 NR hunters for that unit.

Good luck, and I hope you like salt

 

[Hausser1]

Is there a chance the sabot got ahead of the bullet?? Doesnt seem like it but weird things happen.

A couple years ago I was checking my MV's with a ProChrony when it gave me wild readings. Upon inspection, I could see where the sabot smacked the readout face and I had to send it in for repairs. Between shipping and repairs, it cost me half the price paid for the unit new. I had it ~15 feet out in front of my bench. Now when I chrony muzzy shots, I'm at least 30-40. So far, so good