Chronograph

I like my Pact XP pro chrono....the parts for the sensors are cheap or so I've been told I got the IR version so I can use it indoors as well as outdoors, I like having the "brains" on my bench along with a printer.....as soon as I get the info I want I print it out and put it in the case with the ammo.

TooManyToys said:

Yes, this correct. up to 9 strings of 99 shots at a time.
Quality unit, especially for the price.

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I am tempted to invest in one (ProChrono) just to see how it works out with the accessories. I am curious about the PC interface and the cost is really inexpensive. I'll never give up my Oehler but there is always room for another chronograph.

Ron

While I am not 100% on this it looks like the Pro Chrono Digital will record and save 9 strings of 99 shots so that should get you what you are looking for.

They also offer a USB interface for a PC that uses their own software. I have no clue how good these things are but the advertising looks good.

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Thanks, looks good.

Why don't you average 25 rounds, record it, average the next 25, total the two averages and divide by 2?

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Does that create a true average, extreme spread, standard deviation of 50 shots, or is that simply an average of two averages?

I will bet someone in college statistics would be able to give a good answer, but I believe, to obtain the correct statistics for 50 shots, I will need the 50 shots as data points.

Just a note on the Pro Chrono. I had to deal with customer service on replacing some parts.....My wife killed one of the sun shield supports. They were very responsive, very quick and very reasonable........as in free.

It does well in bright conditions and reduced light but not REALLY reduced light as in thirty minutes before sun down. Very late in the day is not good but I do mean late in the day.. I probably should not have been trying to test a load then but it had gotten late when I finished and tried to squeeze in a reading.

Otherwise...very reliable, not quirky. Great customer service.

SlamFire1 said:

Thanks, looks good.




Does that create a true average, extreme spread, standard deviation of 50 shots, or is that simply an average of two averages?

I will bet someone in college statistics would be able to give a good answer, but I believe, to obtain the correct statistics for 50 shots, I will need the 50 shots as data points.

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I am not a statistician, I really could benefit from understanding it better!

So anyway, I was wondering about a different question. But to try to answer yours, if you have 2 sets of numbers and combine them together, you can use that in excel to get your avg and SD. ES is easy. I believe the more shots you put into a group would increase the chances of increasing your ES, and not do much to the SD or avg. As long as you measure the shots all in the same conditions, and you don't let one of the rounds warm up while sitting in the hot chamber of your gun, then it should be a practical way of getting the stats you want.

But my big question is how many rounds do people usually use to feel comfortable that they have good numbers? I use either 5 or 10. But if I shoot more I see velocities increase as the chamber warms up.

SlamFire1 said:

Thanks, looks good.

Does that create a true average, extreme spread, standard deviation of 50 shots, or is that simply an average of two averages?

I will bet someone in college statistics would be able to give a good answer, but I believe, to obtain the correct statistics for 50 shots, I will need the 50 shots as data points.

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Depends on how you go about it. I have an old print out here with some velocities for load data. We can use 5 shots as the example. Numbers are in FPS (Foot / Second).

3157
3198
3177
3207
3164
-------
15903

So 15903 / 5 = 3180.6

So the Mean (Average of 5 shots) is 3180 FPS.

If I add the first 3 shots and then the last two shots I can add those two numbers and then divide that by 5 and the mean will be the same. The standard deviation is based on a deviation from the mean. The problem is the formula for standard deviation is a little complex.

However, as mentioned, all of the data can be easily done using Excel Functions in an Excel spreadsheet. The pain in the butt with that is all the data needs to be entered into the spreadsheet. So if I shoot 10 strings (10 different loads) of 5 or 10 shots each I need to enter between 50 to 100 numbers into my Excel spreadsheet. That being a PITA!

This is where a Chronograph is nice that can interface with a PC and either populate an Excel spreadsheet with the data in CSV (Comma Separated Value) format or have it's own software to create a populated table with all the data.

So in conclusion dumping the data manually into an Excel spreadsheet is a PITA. Having Excel do the math functions for Max, Min, Spread, Mean and Standard Deviation is relatively simple assuming the user has Excel.

That would be my take on all this anyway.

Ron

When developing loads I expect a long day at the range so setting up my Beta Chrony is not an issue. Also note that if you shoot too low over a chronograph that results tend to vary, make sure that the BULLET PATH is slightly above the ventre of the verticle displacement between the sensor and screen i.e. your scope cross must be circa 2" higher than the centre line.

Like a previous poster I also get ticked off with having to refresh my memory with reading the manual. Could not be bothered. In the early days I always recorded my results on paper, I have since bought a small netbook which I uses.

As far as the calc's go, almost all of us have MS Office. Excel has all the functions standard. Here is an extract from my log. I hate fiddly bits of paper and want to view my results live and compare them immediately.

The answer would be the same for the average but not for the min and max or the std dev.

Andrew Leigh said:

Like a previous poster I also get ticked off with having to refresh my memory with reading the manual.

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I agree.

I use my chronographs so infrequently that I have to refresh my memory on its use about every time I drag it out.

I use my chronograph a few time a year, usually I will have some loads to test out, do a couple of sessions with the chronograph and then put it up for several more months.

F1 chrony has worked just fine for me. Should be able to get one for less than one benjamin

"Like a previous poster I also get ticked off with having to refresh my memory with reading the manual."

Yes, and being the previous poster I will add that I was specifically griping about the "shooting chrony" brand of chronograph. Why can't they just label the buttons properly and after one or two uses you could operate it without having to drag out the manual again???? But I've been told that I like to whine...