Got a chronograph, now what?

[edward5759]

I attached a small chain to mine, that was 15 feet long that way I had the same distance from muzzle to measurement each time.
I found that some people cant read a tape measure!

Found some key chain that was 15 feet lone at Home depot so I used it.

 

[jmr40]

Buy a brick, at least 500 rounds of fairly good 22 ammo. It doesn't need to be expensive target ammo, just something that the velocity will be pretty consistent on. On each range trip fire 5 rounds or so of the 22 ammo and record the average velocity. Use the same 22 rifle for this each time BTW.

Even with expensive chronographs the velocities they record will vary quite a bit because of differences in the sun's angle, and intensity. Temperature and other atmospheric conditions can effect velocity as well.

If you get readings with the 22's that are higher or lower than normal then you should expect to get the same with the centerfire ammo you are testing that day. Sometimes even at different times on the same day as temperature and the suns angle changes. If you are using the chronograph for more than an hour I'd recheck with the 22's occasionally.

If you get normal speeds with the 22's but your centerfire ammo is shooting faster than expected then you know the load may be a little too hot. If you are getting faster than normal speeds with both the 22's and your centerfire ammo it may just be that your chronograph is recording speeds a little fast in those conditions. This helps give you a better idea as to whether your loads need tweaking or not.

 

[4runnerman]

JMR40-You bring up some valid points. I think what most likly is happening is as you state-The bullet is going faster,not because the crohny is faulty but because out side temp is causing the bullet to go faster. The same load shot on a 40 degree day will shoot hotter and faster on a 90 degree day. The chrony is just simply showing you the difference temp can make. I know some bench shooters that will set there ammo in the sun shine before a match to heat them up and i also know some that will keep them in the shade.

 

[GP100man]

I started with a BB rifle with mine ,then a 22 , I had to ease my nerves into it !!

More gooder readings at 15-20 feet, muzzle blast made me pull all my hair out until I figured it out.

On a real brite day I use a translucent 5 gal bucket to difuse the lite.

Also I use skewers marked hi enuff for a scope to line up with .

The skewers break when hit the steel rods jerked mine of the table when hit ! & NO there were`nt a hole in the chrony !!!


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