Shooting Chrony differences in fps

vluc · May 5, 2002, 09:25 PM

I have had several folks relay to me that they have experienced differences in the fps stated by the shooting chrony versus other chronographs - only about 15-20.

Has anyone else experienced that? Curious as it would have an impact (slight) on the loads I am making and give me a touch more cushion with the power factor.

444 · May 5, 2002, 09:36 PM

It would be interesting to see how they conducted these tests since there are variations of 10-15 fps from round to round. So I have to assume that they tested both chornos with the same shot. Therefore they would have to be the same distance from the shooter. I thought about conducting a similar test with my Shooting Chrono. It will fit in between the skyscreens of my friends chorno. Therefore I could fire a single shot through all four skyscreens at the same distance.

Redhook · May 6, 2002, 03:36 AM

I would be curious to see the results as well. 444, I don't think you'd have to go through the trouble of fitting one inside the other. Even if they were lined up end to end, you should still see the same velocity variations between the two sets of results. It's all physics once the bullet leaves the barrel. The second chrono will be slower, slightly, but still should show the same variation.

-Red-

444 · May 7, 2002, 12:19 PM

Sitting my Chrony inside my buddies skyscreens occured to me simply because it would be no trouble. Just sit it down and shoot. One thing to keep in mind is that there are variations from one shot to the next even with the most carefully loaded ammo. Then you factor in exact distance to the target, which cylinder of a revolver the round is fired from, the position of the sun, etc. I realize that this is all being cut pretty fine but my point is that I feel my chronograph gives me a pretty good estimate of my velocity. If I somehow found out that it wasn't exactly precise, I wouldn't lose any sleep over it. Especially if you use the same chrono all the time, which would allow you to compare results even if they arn't exact numbers. Even if you compared two chronos under exact conditions, who is to say which one is right ? Just because one cost more than another does that automatically mean that it is correct and the other one isn't ?

C.R.Sam · May 7, 2002, 01:33 PM

Don't forget to record conditions when you chronograph a load. At least temp. Altitude, humidity, barometric pressure all have influence but temp is the biggie with many powders.

Temp of gun chamber and ammo will usually make a measurable difference too.

Sam

May 5, 2002, 09:25 PM	#1
vluc Member Join Date: August 11, 2001 Posts: 53	Shooting Chrony differences in fps I have had several folks relay to me that they have experienced differences in the fps stated by the shooting chrony versus other chronographs - only about 15-20. Has anyone else experienced that? Curious as it would have an impact (slight) on the loads I am making and give me a touch more cushion with the power factor.

May 5, 2002, 09:36 PM	#2
444 Senior Member Join Date: November 20, 2000 Location: Ohio Posts: 3,968	It would be interesting to see how they conducted these tests since there are variations of 10-15 fps from round to round. So I have to assume that they tested both chornos with the same shot. Therefore they would have to be the same distance from the shooter. I thought about conducting a similar test with my Shooting Chrono. It will fit in between the skyscreens of my friends chorno. Therefore I could fire a single shot through all four skyscreens at the same distance.

May 6, 2002, 03:36 AM	#3
Redhook Senior Member Join Date: January 25, 2001 Posts: 254	I would be curious to see the results as well. 444, I don't think you'd have to go through the trouble of fitting one inside the other. Even if they were lined up end to end, you should still see the same velocity variations between the two sets of results. It's all physics once the bullet leaves the barrel. The second chrono will be slower, slightly, but still should show the same variation. -Red-

May 7, 2002, 12:19 PM	#4
444 Senior Member Join Date: November 20, 2000 Location: Ohio Posts: 3,968	Sitting my Chrony inside my buddies skyscreens occured to me simply because it would be no trouble. Just sit it down and shoot. One thing to keep in mind is that there are variations from one shot to the next even with the most carefully loaded ammo. Then you factor in exact distance to the target, which cylinder of a revolver the round is fired from, the position of the sun, etc. I realize that this is all being cut pretty fine but my point is that I feel my chronograph gives me a pretty good estimate of my velocity. If I somehow found out that it wasn't exactly precise, I wouldn't lose any sleep over it. Especially if you use the same chrono all the time, which would allow you to compare results even if they arn't exact numbers. Even if you compared two chronos under exact conditions, who is to say which one is right ? Just because one cost more than another does that automatically mean that it is correct and the other one isn't ?

May 7, 2002, 01:33 PM	#5
C.R.Sam Senior Member Join Date: October 30, 1999 Location: Dewey, AZ Posts: 12,858	Don't forget to record conditions when you chronograph a load. At least temp. Altitude, humidity, barometric pressure all have influence but temp is the biggie with many powders. Temp of gun chamber and ammo will usually make a measurable difference too. Sam