chrony setup

ive got a chrony for the weekend and im just wondering how far away from the rifle i should set it up


thanks

lucas

I like to set up in increments that equal the screen spacing so I can back up to the muzzle for
an actual MV because even at 15 feet there is a loss of velocity.

Example: screen spacing is 4 feet I will set the screens at 8 Feet, 12 feet or 16 feet depending
on the size of the rifle and calculate backwards from the front screen the loss from the front
to the back screen. If I have a drop of 10 ft/sec between the front screen and the back and I'm at 8 foot from the muzzle I just add 20 ft/sec to the velocity and I am very close to the
actual muzzle velocity.

I hope that makes sense the way I explained it .

J E CUSTOM
 
If you have never used a chrono before be real careful with your setup so you don't shoot it.

I set the chrono up with my scope on low power and aim at a target 100 yds away, that way I can see the diffuser supports and how high above the chrono I am. Then I switch to high power and shoot at the target with no concerns.

Stu.
 
for @J E CUSTOM

15f or 16 f. or more

why so important?

ok, the blast d'ont touch my screen but....

when I use my soft from ipod touch, I must input the distance from my gun

so he (soft!!) can compute the real(?) speed to exit of the barrel?

no?

thank you
 
for @J E CUSTOM

15f or 16 f. or more

why so important?

ok, the blast d'ont touch my screen but....

when I use my soft from ipod touch, I must input the distance from my gun

so he (soft!!) can compute the real(?) speed to exit of the barrel?

no?

thank you

Yes !

The reason is that when figuring drops at long distances the actual muzzle velocity is important
and the chronograph ed velocity is slower because of the distance the bullet travels before it
enters the first screen. the reason I measure the way I do is because I dont use anything but
simple math to obtain the true velocity, so I have to be close to the distance i described.

So if a person doesn't have or use a pocket computer he can get true velocities this way.

J E CUSTOM
 
If you have never used a chrono before be real careful with your setup so you don't shoot it.

I set the chrono up with my scope on low power and aim at a target 100 yds away, that way I can see the diffuser supports and how high above the chrono I am. Then I switch to high power and shoot at the target with no concerns.

Stu.

Not bad advise...however this is what I was doing with my new CED M2 I got for my birthday last month and still ended up shooting it! Long story...and embarrising so I will save the details. I baught a laser bore light to set everything up and help correct the problem.
 
j.e. is there a calculation you have to do before you get your final result i thought it was just get some numbers and average it and there ya go? im new to all of this so excuse my stupid questions

lucas
 
JE:

I didn't realize a chrony gave two speeds, one at front screen and one at back. Is that really true? I thought you got the speed from front to back??
 
Lucas.
most chronographs sum up all of the velocities and give you- Max velocity, Minimum velocity,
Extreme Spread, Standard deviation and average velocity.

If yours doesn't then yes you add all of the velocities and divide by the number of shots
and you will get the average velocity and other numbers if you look at highs and lows.

But the velocities you get will be slightly slower than the actual muzzle velocities because of
the loss of velocity between the barrel and the chrony.

This loss is not important at short ranges for drop charts but at long distances it can mean
the difference in a hit or a miss.

Varminator.

The Oehler 35p has Three screens and it gives you the velocity of two separate sets of
screens that compare velocities (A proof screen against the other set of screens) to verify
the velocities and if the two velocities are to far apart it gives you an error message so you
can delete that round and not skew/contaminate the other shots with a bad number.

And yes it uses the first two screens for the proof channel and the first and last screen for
the actual velocity that is why the first set of numbers on the print out are always a little
slower than the actual velocities because of the screen spacing on the proof is 2' and the
actual velocity screens are 4 feet (If set at 4 feet spacing).

This is one of the reasons I really like the Oehler 35p. It checks it's self for accuracy.

That's why I set my chrony at 4 feet intervals . my screens are set at 4 feet and I can
get the velocity drop from 2 feet to 4 feet and add that to the estamated velocity drop
from the muzzle for an "estamated" muzzle velocity.

J E CUSTOM
 
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