Question about measuring bullet muzzle velocity

[JackO]

Are there any general rules how to measure muzzle velocity of a rifle bullet? What distance from the muzzle should the chrono gates be set up at?

 

[SJan]

Read the instructions that came with your chronograph.

Mine says 5' for 22 rimfire, 5-10' for pistol and "at least 10' " for rifle "to protect from muzzle blast"

 

[01bmf]

I use 10' as my standard.

 

[MRE]

Are there any general rules how to measure muzzle velocity of a rifle bullet? What distance from the muzzle should the chrono gates be set up at?

Theoretically the muzzle velocity must be measured as the bullet exits the muzzle. Any farther than that and you have some deceleration. Practically the muzzle blast will damage the chronograph if you stuck the muzzle right up to it, and the flash will cause the chronograph to not see the bullet unless you are far enough away.

10ft seems to work pretty well for me. The difference between the muzzle velocity and 10ft away isn't really significant.

 

[beaker]

I have a Magnetospeed chrony which measures the speed at the muzzle. It works great.

 

[mac1911]

I have a Magnetospeed chrony which measures the speed at the muzzle. It works great.

I seen that thing on youtube a while back, looks like a decent simple unit.

 

[BostonBullit]

This thing looks interesting... Know the velocity from the muzzle out to 100yds..

http://www.mylabradar.com

 

[TBalls]

This thing looks interesting... Know the velocity from the muzzle out to 100yds..

http://www.mylabradar.com

That does look cool. I shudder to think what it will cost.....

 

[Almostelmo]

That does look cool. I shudder to think what it will cost.....

Based on some quick googling, supposedly it'll cost around $550.

 

[liketorace]

Late to the party, OP, but FYI: instructions on the Competition Electronics chrono advise far enough away to avoid muzzle blast affecting measurement (or blowing it over) and recommend 10-15' for a rifle.

 

[Steve Marshall]

I bought an Oehler 33 about 35 years ago. I found it best to have the first screen about 15" from the muzzle. Don't know what the instructions said anymore. So, with a 4' spacing, my velocity is taken at 17'. Trust me, the difference from muzzle velocity to 17' velocity is minute.

 

[Smokewagon]

I have a Magnetospeed chrony which measures the speed at the muzzle. It works great.

Pricey and limited to rifles mostly, but awesome and accurate. Had a chance to see one in use a while back. Very nice.

 

[beaker]

Pricey and limited to rifles mostly, but awesome and accurate. Had a chance to see one in use a while back. Very nice.

Yup i use the uzi to check 9mm loads as you must mount the sensor bayonet to the barrel. It has two magnetic field sensors that calc velocity coming out of the barrel and it does work great. Records strings of any length and writes all the data to an excel spreadsheet on a micro SD card so you can archive your chrony data and compare loads. You can quickly start the next string with a couple of button presses. It will also work on many fixed barrel wheel guns. Not for an auto loading pistol though.

After about 20 months the V1 computer unit died. I emailed them and they said ship it back. I had a brand new V2 unit 4 days later. They didnt even ask when I bought it. Cant say enough good things about them.

Sent from my Galaxy S4 using Tapatalk Pro - typos are from the GD auto correct unless they are funny substitutions those I'll take credit for.

 

[Smokewagon]

Magneto needs a rail mount option so I can slap it on my Glocks...

 

[55_grain]

Let your chrony tell you.
I tried to measure some magnum pistol velocities from a few feet and kept getting errors and bogus numbers...it was a load with a lot of flash and blast. Moved out to 10' and it works fine...