Chrony oddities

tools · December 15, 2007, 11:14 AM

Every so often I get a wierd chronograph reading on a load, like 1100 when all the other bullets from the same load are reading 2800. Does anyone else ever see this, and what might be the cause? I'm sure the catridges are built up the same, and have the same powder charges, components, etc.

Frenchwrench · December 15, 2007, 12:36 PM

Shadow/sunlight at an angle/glitch in skyscreens/ you see em every once in a while.Drop out the odd one and average em out.Unless you feel or hear that the shot was different....then you have a reloading problem.

RDub · December 15, 2007, 01:02 PM

What chrono are you using?

I have seen this every once in a while. Usually, if I have a glitch, it's on bluebird sunny day.
My Oehler 33 has a 'ignore' button that I can delete a random reading from the rest of the string.

Scorch · December 15, 2007, 01:08 PM

Try to make sure your screens are far enough away from the muzzle blast. Many times, you will get a reading off of the shock wave, which travels at the speed of sound (roughly 1,100 fps), or you will only get one screen triggered, which will give you the same reading.

steveno · December 15, 2007, 02:07 PM

you don't say what caliber but it could very well be muzzle blast. magnum loads in revolvers and rifles will cause crazy readings on a chronograph

firechicken · December 15, 2007, 08:56 PM

Also be aware of other shooters on the next bench. I've often had the muzzle blast from a neighbor contaminate my string.

amamnn · December 17, 2007, 12:31 AM

Muzzle blast and flash can both give you odd readings. Also if your bullet is not passing through the center of the sensor area, at the ideal height above them, you can get odd readings. Your intermittent oddball reading sounds like this last problem.

You can build blast/flash screens to use just like the ones in the testing labs, but they are cumbersome to haul around and take extra time to set up and tear down. If you have a laser boresighter, you can use it to find out just where your bullet will pass through the sensor field. Do remember to remove it before shooting.

December 15, 2007, 11:14 AM	#1
tools Senior Member Join Date: October 13, 2006 Posts: 124	Chrony oddities Every so often I get a wierd chronograph reading on a load, like 1100 when all the other bullets from the same load are reading 2800. Does anyone else ever see this, and what might be the cause? I'm sure the catridges are built up the same, and have the same powder charges, components, etc.

December 15, 2007, 12:36 PM	#2
Frenchwrench Member Join Date: January 19, 2005 Location: Indiana but my land is in Colorado Posts: 80	Shadow/sunlight at an angle/glitch in skyscreens/ you see em every once in a while.Drop out the odd one and average em out.Unless you feel or hear that the shot was different....then you have a reloading problem. __________________ When in trouble, when in doubt, run in circles, scream and shout.

December 15, 2007, 01:08 PM	#4
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	Try to make sure your screens are far enough away from the muzzle blast. Many times, you will get a reading off of the shock wave, which travels at the speed of sound (roughly 1,100 fps), or you will only get one screen triggered, which will give you the same reading. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services

December 15, 2007, 08:56 PM	#6
firechicken Senior Member Join Date: April 17, 2006 Location: Savannah, MO Posts: 224	Also be aware of other shooters on the next bench. I've often had the muzzle blast from a neighbor contaminate my string. __________________ The only thing necessary for the triumph of evil is for good men to do nothing. - Edmund Burke

December 17, 2007, 12:31 AM	#7
amamnn Senior Member Join Date: May 13, 2006 Location: WA, the left armpit of the USA Posts: 1,323	Muzzle blast and flash can both give you odd readings. Also if your bullet is not passing through the center of the sensor area, at the ideal height above them, you can get odd readings. Your intermittent oddball reading sounds like this last problem. You can build blast/flash screens to use just like the ones in the testing labs, but they are cumbersome to haul around and take extra time to set up and tear down. If you have a laser boresighter, you can use it to find out just where your bullet will pass through the sensor field. Do remember to remove it before shooting. __________________ "If the enemy is in range, so are you." - Infantry Journal

December 15, 2007, 01:02 PM	#3
RDub Member Join Date: November 13, 2007 Location: Southern Oregon Posts: 30	What chrono are you using? I have seen this every once in a while. Usually, if I have a glitch, it's on bluebird sunny day. My Oehler 33 has a 'ignore' button that I can delete a random reading from the rest of the string.

December 15, 2007, 02:07 PM	#5
steveno Senior Member Join Date: June 18, 2004 Location: Minden , Nebraska Posts: 1,407	you don't say what caliber but it could very well be muzzle blast. magnum loads in revolvers and rifles will cause crazy readings on a chronograph

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