Using chronograph question

[Clay]

Gents,
I'll be trying out a new chrono this weekend and was curious if I should beware of muzzle blast. I'll be trying it with 44magnum and S&W 460. That 460 has one heckuva concussive blast, so should I worry about damaging the unit? Should I have it a certain distance from the muzzle? All help appreciated. Thanks!

[brickeyee]

The first screen needs to be far enough away the muzzle blast does not trigger it instead of the bullet.

15-20 feet seems to work most of the time.

[Jim Watson]

I have not worked with a handgun larger than a .44 magnum, for which 10 feet from muzzle to start screen is enough. That works for most rifles although I usually go to 15 just to be sure.

[4runnerman]

I think in the instructions it mentione's at least 10 feet away

[700cdl]

I keep about 10 ft. away with all of my guns,no problem. Make sure you sand bag the tripod or use some way to stabilize it so it won't get knocked over by the concusion or wind.

[Unclenick]

We had a post within the last few months in which a member described having trouble with false triggering from his .338 Lapua Magnum until he moved the screen back to 18 feet. I use 15 feet to the center between the sensors because 15 feet is what is used by ammo makers, load manual authors, and in magazine articles. If I intend to compare what I'm getting to any published data, that's where I need to be. The exception is for military loads that use 78 feet (26 yards) for rifle (bring your spotting scope to read the display for that distance). That's a holdover from when equipment had poorer resolution and response speed than today, so the start and stop bullet detectors were therefore set a lot further apart.

In any event, erratic readings and impossibly fast or slow readings are what you look for. You can be as close to the gun as consistent readings allow. I've never heard of concussive shock damaging one of these instruments. If it won't shatter glass, you should be good to go.

If you want to use the longer chronograph distance but are concerned about shooting the screens or, if you have an integral display, shooting the computer itself, I recommend the laser bore sighter setup. With action open and empty, you set the gun up on bags so the sights correctly align with the target. Insert the laser bore sighter and turn it on. Check that the sights are still right. Walk out to the chronograph and adjust the stand until the laser is centered in the the front and rear screens. I just use my palm to find the beam. Some use a target center. Your choice. Any cheap bore sighter will do. You can usually find a good enough one for under $30 somewhere.