Just curious for IPSC how many of you would set up your chrony. I have seen at some matches where a big box was used over the chrony, and yet have seen others placed under a tent (also for the rain I would think), and then others with just the diffusers or on a cloudy day, just the rods. Recently I chronied a few times and got some big differences in the average FPS from the same load. At the advice of a local shooter, I covered the chrony with an IPSC target white face down, and noticed a consistant 30fps lower reading than without the target. All rounds shot from approx. 13feet away.
chrony set up.
- Thread starter maurice
- Start date
- Location
- Halifax - NS
The primary reason we use boxes is to make the chrono reading consistent throughout the day or event.
A repeatable artificial light source (either incandescents or IR) in the same position all the time.
No clouds, no setting or rising sun. It's that simple.
A repeatable artificial light source (either incandescents or IR) in the same position all the time.
No clouds, no setting or rising sun. It's that simple.
- Location
- Halifax - NS
Depends on how precise and repeatable you want to be. Box, No Box - CED or Chrony - or Ohler - you can go nuts on getting the best setup.
A guy chronoing for himself is a significantly different beast than a match with 250 competitors run over 4 days (with requirements for calibration ammo, etc) like the one we'll be at next week.
Maurice getting wide Extreme spreads is not uncommon if you handgun doesn't like the bullet/powder charge combination.
Persoannly when I am developing a load for my handguns I look for Standard Deviations under 10 when shooting strings of 10 rounds. If you do enough of it you will soon learn some guns like one load over another. Not sure if SD's under 10 relate much to accuracy of a load but it works for me.
In your case you might just have a load combination your gun doesn't like. Move up and down the ladder in 1 - 2 tenth of a grain increments and see if the Extreme Speads tighten up. Your Chrono technique might be just fine.
Take Care
Bob
ps for personal load testing I have never bothered with a box set-up but I do make sure my Chrono is out of the wind if there is any. Like Sean said chronoing for personal use is not the same as doing it for a major match.
Maurice over 8 rounds an Extreme Spread of 30fps is nothing to worry about.
Best Ext Spread I have achieved was 14 with a SD of 4 using 4 Gr. Titegroup under Can Pro 124 gr. plated out of my M&P Pro. The same day 4.1 gr of Titegroup gave an Ext. SP of 43 and a SD of 14 out of the same gun using the same bullets.
Take Care
Bob
This is what you need, a chrono coffin.
You will also need IR sensors for the chrono too.
The chrono distance from muzzle to the start sensor is 10 feet for IPSC/IDPA and USPSA.
I use this setup all the time at matches.
You will also need IR sensors for the chrono too.
The chrono distance from muzzle to the start sensor is 10 feet for IPSC/IDPA and USPSA.
I use this setup all the time at matches.
