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Old August 21, 2011, 02:13 PM   #1
ah141nj
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Chrono setup

Whats your method for setting up your chrono?

Tried a laser sighter in the rifle barrel..not seen in sunlight

Tried tying a string to the barrel and out to the chrono...not too accurate.
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Old August 21, 2011, 02:17 PM   #2
Unclenick
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I've had good luck with the laser sighter. Some will be brighter than others, though, and the green lasers are easiest to see. Did you check batteries in the laser? You can lay a piece of cardboard over the sky screen diffusers as a shade so the laser has less competition with sunlight.
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Old August 21, 2011, 03:14 PM   #3
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2 bubble levels in the sky-screen rail, a 15' long piece of string with 2 beads on it, a felt marker pen & a tripod with a gear-driven center column. One bubble level is left-right, for horizontal leveling, the other is front-rear for directional leveling.
OK here's how.

To set up the first time:
Level the rail front to back & sideways with the tripod's head adjustments.
Wind up the center column about 1/2 way.
Raise/lower the leg sections till the center of the swept area is aligned with the bore of the unloaded, benched gun. Do this with the "START" screen 3"~4" yes INCHES in front of the muzzle.
Mark the leg extension with the sharpie. (That way you can re-create the height without doing all this messing about again)
Trail the string till the bead tied to the string at 10 or 15 feet (your choice) is touching the muzzle. Measure to the center of the sky-screen rail.
Tie the end of the string to the rail.

*set the target up wherever you want to shoot for group at this point*

Wind the center column up/down till the center "sweet spot" is in line with the muzzle & the bullseye.
Mark the center column extension used.
You're done.

To re use:
Set all the leg extensions to the marks, set the column extension to the mark.
Level the rail.
Run out the length of string till the bead of choice touches the muzzle.
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Old August 21, 2011, 07:18 PM   #4
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Walk out 10 feet and set up tripod and chronograph, look left at rest, look right at target, adjust for height.
Go back to rest and look thru sights to target, if I'm not going to hit the chrony, Fire!
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Old August 21, 2011, 09:20 PM   #5
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I started using a lazor sighter also and it works great. A lot faster to set up. I just put a white piece of paper above the sensors and adjust from there.
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Old August 22, 2011, 10:38 AM   #6
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It occurs to me to mention that lasers often come with reflective target material that makes the lasers more visible at long distances or in bright light. The cheapest of these appear to be no more than the reflective tape you get for signs or vehicle bumpers or bicycles. I'd try a little of that on a piece of cardboard if you can't see the thing. Take the sighter laser with you to the bike store and try it on some samples to see if any look brighter than the others. A red tape might get you less ambient white light reflection while letting you see the spot well.
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Old August 22, 2011, 11:13 AM   #7
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Lasers? What I don't understand is; what's so hard about setting up a chronograph?

First, you set up a target, at whatever range you choose. Then you set the screens, or the box if you're using a chrony, on the tripod out in front of the gun at whatever distance that's dictated by what you're going to be using that day. Magnum rifles and handguns need to be at least 15 feet in front of the gun.

Get back to your firing point, then sight past the screens/box to allow clearance and line up the screens right left and inline with the bullets path. DONE!

My pact chrono is not too critical about exactly where the bullet travels above the screens. Anywhere from 6" above to 18" is fine, and it can be off center by 6" if it above by a foot. I do NOT use the diffusers.

My question is; I see a lot of reference to some using levels to tweak the screens. Why? Is this necessary? I try to have the screens parallel to the ground and bullets flight. I can't see why anything has to be perfectly level.
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Old August 22, 2011, 10:46 PM   #8
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set-up?

I think highvel and snuffy got it right. Set the chrony up as mentioned, and bang away. Just don't shoot the damn thing! Pretty simple.
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Old August 23, 2011, 01:04 AM   #9
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I set it up with all the care in the world, ''but it takes too long so'' so I tried the next thing and it is set it up roughy then get behind your rifle turn the scope to the weaks power setting and check to the left then the right you should see the reflector arms and no crony box I use a mid point path to ensure I'm in the middle fastest and easiest for me.
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Old August 23, 2011, 06:44 AM   #10
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For a reference point I have white freezer tape on the screen uprights from the 6" to 8" position above the chronograph top. I set my chronograph on a large up side down plastic nursery pot about 15 feet in front of where I shoot and can adjust the height of the chronograph by adding and subtracting nested plastic flower pots. When trying out new loads I use large bales of compressed peat moss as a bench rest and have the top of the bales of peat moss at the same height as the taped area on the chronograph uprights at the same level as the target down field so they are all in line. I guess one can tell I am in the nursery business and own my own property where I have set up a 25 yard, 50 yard and 100 yard area to shoot.
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Old August 23, 2011, 08:11 AM   #11
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The purpose of the laser is to speed the setup. No going back and forth to the firing point to check that you won't be firing at an angle through the screens. No walking around the unit and stepping back to see if the target and firing point both seem aligned. This is especially useful when you are running a pair of chronographs to measure ballistic coefficients, so one unit is a good distance from the firing point, or if you set a single unit out at 78 ft to copy military rifle velocity measuring distance. It's less an issue if you are looking for velocity alone, as you don't need to hit a target at the same time, but just the bigger backstop.

The level is the same way, assuming your range is flat. Using one of those little round ones sitting between the screens while you tighten the tripod takes only glance. It's not high precision, it's just quick.

The guys with 1 foot screen spacing won't notice alignment errors as much, so their setup probably feels easier. Those of you who've set up an Oehler with the 4 foot spacing pipe that's recommended for rifle and it's independent lamp stands at each end, will know how annoying the trial and error approach can be to getting gun and target alignment straight. It takes only 1/4 the angular error to get the same amount of stop screen diffuser in the opening of the front screen as it would with short screen spacing.

I set up the CED M1 with 2 foot spacing for casual readings. The newer M2 unit seems to be fixed at 2 foot spacing where the old one could do 2, 4, or 8 feet. But the new one has a 16 MHz clock instead of 4 MHz, so, at 2 feet, it has the same resolution the old one did at 8 feet. With the old one, I use the 4 foot beam on the tripod when I'm using it in tandem with the Oehler, so that both have the same resolution. It just takes more care to align that long space satisfactorily.

If you need the careful alignment, as for 78 foot readings, and can't get a laser visible, take a length of plastic plumbing pipe equal to your screen spacing with you. Lay it over the sky screens and use it to bore sight a spot 6" below the gun muzzle and 6" below the target POI at the other side. You will still be going back and forth around the unit, but precision will be higher than eyeballing and you probably won't have to go back and forth to the firing point until you get it right. Again, you'll notice this more with longer screen spacing than with short.
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Last edited by Unclenick; August 23, 2011 at 08:20 AM.
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Old August 23, 2011, 08:20 AM   #12
wogpotter
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Quote:
I see a lot of reference to some using levels to tweak the screens. Why?
Its not essential, but it does make setup easier as you can just level the rail quickly & then move left/right & up/down to get the path right. I look down on the rail during setup so it saves me walking back & forth several times to setup, look through the screens to check, then walk back.
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