How do you guys set up your chronogrph?

Do you set it up right on your range bench just ahead of the muzzle of your rifle, or set it up in front of the bench on stands or something?

I guess when I buy one it will say in the instructions ,,,or not.

quote:

Do you set it up right on your range bench just ahead of the muzzle of your rifle, or set it up in front of the bench on stands or something?

NOOOO....Please don't...

That's a Great question and yes it is usually answered in the instructions when you buy. Many people don't read instructions and totally ruin a great piece of new equipment.

I set mine up at 12-15 feet when shooting my rifles and 3 feet when shooting my bows.

If you ever shoot a MLer through it (Which I wouldn't advise) w/ sabots, you have to set it up further because the sabot itself will break the screen if it hits it.

The reason for setting up the chrony at 12' or so is due to muzzle blast, if you set it up to close the blast can break the tiny thin glass on the screen.

Good Luck

Reloader

I've actually seen the sky screens get blown off of a chrony at around 10-12' from the muzzle blast of a Weatherby Magnum.

Have a Good one

Reloader

Mine gets mounted on a camera tripod about 12 feet or so in front of the muzzle. I have, on occasion, knocked one of the sky screens off with the muzzle blast from my 9.3x62 but it is rare. They are very easy to set up - just take your time to verify the path of the bullet is over the sensors and not hitting the sky screen support rods or the unit itself.

Phil

I've been using my Pact I since 1989. I shoot everything I own across it save my shotguns. I shoot from .17 Remington to .378 Weatherby.

I set it up per the directions 10 feet in front of the bench. Never had a problem with muzzle blast. The sensors are set up on the bar I got from Pact. Which I mounted to a quick release that goes on my Bogen 3031.

The first thing I do is set up my target. During the next firing session on the range. I get my rest all set up. Take the bolt out of the rifle and I manually bore sight the rifle and sand bag it in place.

On the next target check I take the tripod and my Pact I and set it 10' in front of the muzzle. I look through the sun screens and align the tripod with the bore of the rifle which I can see since the bolt is still out. I carry the wires with me and just drop them while passing the bench. I don't in any way stop and fool with anything on the bench.

When the Range Master gives the all clear. I proceed to my bench. Pick up the leads and plug them into the monitor on the bench. I double check the alignment of the bore to the target and it's relationship to the sun screen window. If all is ok I'm set to fire. I've used this procedure since 1989 and have yet to shoot my chronograph.

Oh it's always a good thing to let the Range Master know what you are doing and how you are going to do it. That you won't be touching the rifle while anyone is down range doing the target check and the bolt is out of the rifle. That you won't be fooling with anything on the bench.

I have a Chrono Chronograph, been using it for years now.

A chronograph provides useful data but is not to be trusted implicitly. There are things such as instrumentation error. I believe this is due to misalignment. When you consider the short distance between the sensors, around 12 inches, and velocity is calculated based on the time it takes the bullet to cross that distance, the tiniest variation in that distance caused by off axis misalignment will create differences in reported velocities. I have found over the years that values can vary day to day. Velocity averages will never be exact, but I believe they are comparable as long as they are within the Standard Deviation of a previous session,. I believe that you should start off a chronograph session with a “calibration loadâ€. For me this load is something that I have fired before and have confidence in the velocity numbers.

I stick it on a cheap camera tripod that I purchased from Walmart. I level my chronograph using a cheap Laser Level I purchased for under ten bucks at Harbor Freight Tools. http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=54050. I use this to level the Chronograph and use the laser to orientate the center line of the chronograph on my bench rest. I believe this reduces my misalignment error. I have noticed the slightest bump or movement in the chronograph will give radically different velocity readings.

Black powder rifles blow out so much unburnt chunks of powder, that I have had to put my Chrono out maybe 30 feet away or I get display errors.

Acceptable velocities depends on the loads and the rifles. You will find some barrels are faster than others. And as you pop primers in the fast barrels, you will figure out the thresholds for that firearm.

What about those funny numbers , Standard Deviations and Extreme Spreads? The Standard Deviation and Extreme Spread numbers are not as important as what your group looks like on paper. But for those who want a standard, assuming already outstanding on paper performance, I am going to give you some impossible criteria. I asked the gunsmith who barrels my Match Bolt Rifles, this man is Nationally ranked Highpower Competitor, last couple years was in the upper ten, has won the Long Range Aggregate and I think Wimbleton, about his criteria. He wants a long range load that has a SD less than 10 and a ES less than 20. Of all my loads that I have chronographed, and there are many, I have had two or three that met this criteria. But there is a standard for you to shoot at. Pun intended.

The chronograph is a tool, useful for checking velocities. Consistent ammunition is always good, means you have your reloading processes down. But the numbers do not guarantee accuracy. You will find that errors in position, errors due to wind changes, errors due to flinching, are typically larger than your ammunition errors. But it is worth making good enough ammunition that you can concentrate on fixing the other things.

I believe the ISPC standard is 15' from the muzzel to the center of the sensor bar.

I keep a tape with my setup to keep the distance consistant.

I use an Oehler Model 35, so the unit is sitting on the bench with you and not subject to muzzle blast. Although Oehler's instructions call for placing the screens at about a 15' instrumental distance, I usually put the front screen (camera tripod mounted on a 1/2 inch length of aluminum conduit) at around 6 or 7 feet from the muzzle, which is usually plenty. I have my Oehler set for a 4' screen spacing. This reduces spacing error to one-fourth of what you would have with a one-foot spacing. The longer spacing also provides a longer "sight radius" so to speak, allowing you to better align the screens with the bore line, again reducing spacing error.