New Chrono

[alamogunr]

After reading many posts over the last several years, I finally broke down and bought a chronograph. My new CED chronograph arrived yesterday. All I've done so far is read the manual several times. I picked up a tripod on ebay(I know! I know!) and I already have an extra range bag. My reason for posting is I know many here have chrono's and I'm looking to pick up pointers on their use(besides not shooting them). I probably won't be able to take it to the range until next week. In the meantime, I plan to get it assembled and load up a few test loads.

John
W.TN

[JIMinPHX]

When you set it up, make sure that you put it far enough out in front of your muzzle so that the muzzle blast doesn't take it out. It's better to learn from the mistakes of others, than from your own.

[Ed Barrett]

Always carry a spare set of batteries, they give out at the worst possiuble time. The light weight tripods can be blown over by a gust of wind, the Chrono makes it very top heavy.

[Johnch]

Enjoy

May I sujest you don't let "Freinds" shoot over it
If they want to check their velosity , you pull the trigger

As I have had 2 chronographs shot by others

1 was a guy that I bidn't know , he was a guest of a club member that never even ask
The other was a "freind"

Both replaced the chronograph , but in both cases it took time and arm twisting

John

[frankenfab]

Get the cable so you can hook it up to your PC and download the strings to save for your records.

[alamogunr]

Thanks for the advice so far.

I bought the tripod on ebay, hoping to get a little heavier duty apparatus. Somewhere I read that a sack full of sand or some such could be hung from the tripod to give it more stability.

I plan to get two batteries tomorrow. The unit has a place to store the extra battery.

The USB cable came with the chronograph along with the software to use with the data.

I hear you about others shooting across it. At least this chrono has the electronics on the bench and the screens and sensors are the only parts in harms way. Mostly where I shoot, there isn't anyone around when I'm there.

Any additional advice will be welcome.

John
W.TN

[mike in co]

mark your cables at 10, 12 and 15 feet.
i use 10 as my std but think i have used 12 with belted mag.

angle of light is an issue...so early in the am and late eve shots can be an issue.

try to shoot abour 4-6 inches above the eye, try for dead center.


buy spare parts now sow when something hits a sensor or screen you are not waiting for parts...its gonna happen..


other than that let us know how it works....i think it maybe the best on the market...under $800 now that ohler is not available to the public.

mike in co

[Cherokee]

I have a target aiming point right behind the back screen. I aim high, see where I hit, then aim lower if need be. I put a new target spot on the target as needed. I have an Ohler 35. Haven't shot my screens yet, in 20 years ----ops, shouldn't have said that.....

[Matt_G]

Once I have the rifle set on the bench using my bags/rest and the crosshairs are on the target, I take the bolt out and look through the bore to verify that I will clear the screens. Haven't shot one yet and yes I'm knocking on a piece of wood as I type this...
I have the older model CED chrono and really like it. I'm sure you'll like yours.

[KYCaster]

Enjoy

May I sujest you don't let "Freinds" shoot over it
If they want to check their velosity , you pull the trigger

As I have had 2 chronographs shot by others

1 was a guy that I bidn't know , he was a guest of a club member that never even ask
The other was a "freind"

Both replaced the chronograph , but in both cases it took time and arm twisting

John

Good advice, but doesn't go quite far enough. Before you shoot your friend's gun across your chrono check the sight setting on another target. A friend of mine took out both sensors with another guy's gun. The fellow said, "Oh, I forgot to tell you the gun shoots WAY LOW".

Loose gas checks can also cause damage.

Jerry

[Mk42gunner]

The sandbags on the legs of the tripod are a very good idea; there is nothing like that sinking feeling of sqeezing off a shot and seeing your new chronograph tilting sideways as the trigger breaks. Luckily no harm was done, but a lesson was learned; don't set up in the wind without insurance on the stability of the tripod.


Robert

[wistlepig1]

I hang a cord from the center of the tripod and tie a sandbag to it just off the ground. Works for me in windy Colorado.

[Wayne Smith]

If yours is like mine you have multiple adjustments for spread of the sensors. The piece I have to mount my sensors (came with the chrono) is 4'. You get really questionable readings when the chrono is set for 2' and your sensors are 4' apart!

I believe my cables are 15' long, I never measured them. I just set it up as far from the muzzle as it will go without tipping over my tripod. Never had a muzzle blast problem that way, not even with muzzle loaders or BP loads.

[alamogunr]

If yours is like mine you have multiple adjustments for spread of the sensors. The piece I have to mount my sensors (came with the chrono) is 4'. You get really questionable readings when the chrono is set for 2' and your sensors are 4' apart!

I believe my cables are 15' long, I never measured them. I just set it up as far from the muzzle as it will go without tipping over my tripod. Never had a muzzle blast problem that way, not even with muzzle loaders or BP loads.

Wayne: The mounting arm on mine is for 2' spacing. The instructions state that 2' is sufficient with improved circuitry. Since a longer arm is not available, I hope they're right. The arm is also hinged in the middle so it folds approx. in half.

I haven't measured the cables either. The instructions indicate the cables are 20' long. I shouldn't need the full length since I don't have any magnum rifles, although a friend has a .300 Weatherby that he wants to check out. I intend to follow the advice of sighting through the bore before firing.

I'm still waiting for the tripod. Hope it shows up today or tomorrow.
Thanks,

John
W.TN

[BD]

Replace the rods that support the sky screens with wooden dowels, if they get hit they don't damage the unit. I mark mine with magic marker about 5" above the screens and try never to be sighted lower than the marks. This can be tough with the smaller calibers. My unit will see every .45 that passes over no matter what, but the .22s need to be closer and more centered over the screens.

Buy a Home Depot surveyors tripod, Berger or Spectra or whatever, for $70 it's way more stable than any camera tripod, and will last forever. Maybe it's just because I'm used to them, but to me they are much faster to set and align, and the legs are designed to be pressed into the ground with your foot.

Never "sight in" through the chrony. Don't ask why I know this to be a bad thing.

I keep meaning to build a simple steel deflector for mine, just haven't gotten around to it yet.

BD

[Rocky Raab]

My Oehler has orange sky filters, and when using a scope, I always set up so that there's a thin orange line in the top of the scope. That keeps the bullets a couple inches above the "eyes." I carry a cheap tape measure in my range bag so I can set the muzzle to screen distance at 10' for everything.

In years past, I've tested some 30/22 sabot loads that were wild enough to hit the sky filters. More recently, I tested a super velocity rifle (4300 fps+) that blew up some bullets fast enough that debris hit the sensors. Finally "killed" the front senor with one before I stopped shooting that rifle.

Sadly, my Oehler is dying. The circuit boards are still perfect, but the print section is getting erratic - and there are no replacements available. I might end up buying a printing calculator and cannibalizing it to see if I can kludge up a working printer.

[mike in co]

Wayne: The mounting arm on mine is for 2' spacing. The instructions state that 2' is sufficient with improved circuitry. Since a longer arm is not available, I hope they're right. The arm is also hinged in the middle so it folds approx. in half.

I haven't measured the cables either. The instructions indicate the cables are 20' long. I shouldn't need the full length since I don't have any magnum rifles, although a friend has a .300 Weatherby that he wants to check out. I intend to follow the advice of sighting through the bore before firing.

I'm still waiting for the tripod. Hope it shows up today or tomorrow.
Thanks,

John
W.TN

you need to set the distance from muzzle to screen the same...else the results mean nothing.

consistant distance...so the data is comparable to the next or previous session.

a three screen ohler will show velocity drop at 12 over 10 ft....

[Larry Gibson]

All very good advise, let me add;

Use a stout tri-pod and definitely weigh it down with a sand bag if wind is a problem.

I always measure the same distance (I use a tape measure and measure to +/- 1") from the front of the bench to the first screen because I pretty much use the same bench at the range I use. You can also measure from the muzzle or from front rest. The point is to be consistent from shooting session to shooting session if you are going to make comparisons of various loads or conditions.

I have a single shot .22LR with one lot of quality 22LR match ammo that I use as "reference ammunition". I bought 2 bricks (1000 rds) years ago for use with the M10 and then with the M35P and still have most of one brick left. I shot 5 ten shot strings across both the M10 and the M35P and have the summaries noted on the ammo box. Periodically, especially if a serious test session is in order, I fire a 5 shot string of the .22LR ammo from that same rifle across the screens. If the results, given the current weather conditions, are within the parameters of the initial tests then I know all is well. I have a bolt action .308W and one lot of M118SB I use as "reference ammunition" for the M43 PSB. If you do this you will quickly see why consistently placing the start screen a specified distance is important as the variation in summery results can be quite different given different conditions. The variations of mean average velocity, SD and ES will at first seem confusing and you will think you are doing something wrong with your loads. However, there is an acceptable variation in the resultant data, even when two consecutive strings of the same ammo is fired out of the same rifle under the same conditions.

Learn to understand the relation between the SD and the ES, don't chase the SD god! Data from a 3 shot string, just as a single 3 shot group, only provides minimal information. Data from a 5 shot string is better but data from a 10 shot string is a much better measure of any loads performance potential.

This is what I generally look for with chronograph results when working up a new load. There are other techniques for sure but this one is simple and gets me to quality loads quickly. First off with any firearm combination I pick components that are known to give accuracy and performance. I also set a certain criteria of performance with a specific cartridge and then work the accuracy with in those performance criteria. For example; if I am loading for a 30-06 I expect 30-06 velocities, not .300 Savage velocities and certainly not .300 Win Mag velocities. Thus I work up initially in 3 shot groups from a starting load to a top end load from several sources (manuals and loading data). I pay attention to flyers (I’ll accept the called shots). If I have loads giving expected 3 shot accuracy within the expected velocity range for the cartridge (an ’06 in this case so within 100 fps of what I expect) given the barrel length and there are no excessive pressure signs I then load 5 shot strings of those loads within that 100 fps average velocity range. Since I usually test initially with ½ gr increments in an ’06 sized case then there are usually 3 – 4 such 5 shot strings to test. Then, just to be certain, I take the specific load that groups the best (even if the SD and ES are not the best) and load 3 ten shot strings; one of that load, one with .2 gr less powder and one with .2 gr more powder. I then test those 3 ten shot groups. If those 3 groups are within .2” of each other (using an ’06 type sporter) and of sufficiently decent accuracy for the intended purpose I will then select the load with the minimal SD and ES of correct proportion. Yes I could conduct the same test the next day and selct a different load but testing could go on forever that way. The load selected should be well within the mean accuracy capability of that rifle with those load components. If accuracy or velocity do not meet expectations (with a rifle with a know accuracy level) then I will move onto other powders or bullets.

What is a good relationship between SD and ES? In the ’06 example above with the 5 shot string I would expect an ES of no more than 50 fps and no more than 60 fps with a 10 shot string. The SD of the selected load should be within a 20 – 45% fps range of the ES fps. That would be an SD of 12 to 27 fps with a 10 shot string ES of 60 fps. Some like to quote single digit SDs and yes they are nice if there is also a corresponding low ES. In this case a SD of 9 fps or less and an ES of 60 fps is telling us that 1 or 2 shots are outside the actual average. Those would be flyers, especially at longer ranges.

I've been shooting across screens since '75 (Oehler M10, M35P and M43) and have nicked a couple. From that I learned to never shoot an unzeroed gun across the screens, zero first. I set up the rifle on bags on the bench and get into a good solid shooting position and aim at a spot on the berm behind the 100 yard target line. I then go place the target frame with target in front of that spot. I double check the alignment of the rifle to the aiming spot on the target and leave the rifle lined up on the bags (action open and unloaded of course). It is then easy to set the screens out and look back through them to line them up with the barrel. Some minor tweaking is done by simply looking back through the sights (a friend looking through the sights can be a great help here). Sounds complicated to do but the more you do it the easier and quicker it is done.

Just some food for thought as the use of a chronograph can provide you with some very valuable data that will increase your selection of loads to use. It can however, be misleading if not used correctly. Good luck and good shooting.

Larry Gibson

[corvette8n]

While at a garage sale I spotted an old SLIK tripod very heavy duty, it was marked $2.00 so I grabbed it and was carrying it around looking at other stuff, when my wife spotted me with it and keep saying we already had a tripod we didn't need another, I told her to be quiet, I would explain later.
I eventually told her the tripod we already had was a cheap chinese on and this one was way better.
Now I have a worthy tripod for my chrono.

[alamogunr]

Resurrecting an old thread!
I was finally able to get to the range with the new CED chronograph(Don't ask me where time goes when you're retired).
I thought that I would start out with a new .22 CZ rifle since that would give me somewhat predictable results. WRONG! I only shot about 25 rounds and only 5-6 gave a result. The rest displayed an "E1" error. This indicates that the "Stop" screen did not read the bullet. I adjusted everything I could think of without success. Does anyone who has one of these instruments have any ideas what I am doing wrong?

John
W.TN