PVM-21

[Steve Blair]

I guess I am missing the boat $730 and you need a laptop to figure the info needed?? or a hand calculator and a degree in mathematics!

Wayne,

It really is not that complicated. No laptop is needed, your PC at home would work fine. No mathematics degree, either. The "stddev()", "median()", "min()" and "max()" Excel functions do all that for you. If you do not have a copy of Microsoft Office, the Libre Office suite is free, excellent, and includes a (mostly) Excel compatible spreadsheet. If you like, I will be happy to provide you with a copy of my spreadsheet and even provide some free email technical support.

http://www.libreoffice.org/

I agree that their software should do a better job of meeting user expectations. My goal was just to get the data into my spreadsheet which predated the PVM-21 by many years. I have gone through Lotus 123, Borland Quattro, and numerous Excel versions with the many iterations of my evolving data store. If you are really interested in a PVM-21, call Neco and relate the software problems described here and ask what they have done to address them. QuickLOAD is updated periodically, the PVM software probably is, too.

 

[bozo699]

Steve,
I appreciate that, I have several laptops that isn't a problem unless there software is a problem, if you find the time a copy of your excel spread sheet would be greatly appreciated, thank you. waynebezona@cpcinternet.com
Wayne.

 

[CJ6]

Bozo69, I appreciate the offer . I'm looking at the PVM 21 at this time (shooting window size) + the IR feature.

 

[CJ6]

Sleepygator, I have the laptop (2004 Dell with XP- Pro full version). I believe this is a 32 bit system (I'll recheck the spec sheet).

 

[Forum Boss]

One other thing to consider when using the PVM-21 at the range with a lap-top or net-book. If the shooting bench is not covered and well-shaded it may be near impossible to read the lap-top screen. This proved to be a real PIA a couple times -- so much so that I now carry an umbrella to new-to-me ranges if I need to use the lap-top. But this is yet one more reason to run the thing without computer and just write down the numbers.

Data Dumps vs. PVM Software
If it hasn't been clear -- you don't need to dump the data into Excel or other spread sheet -- theoretically. When the PVM software is running you'll have a live table that calculates SD, ES, Mean on the fly, and these tables can have descriptive notes, and even output to graphs. That's pretty cool. When the shot registers you can see the ES/SD change in real instantly.

The problem is I don't think we've ever done more than seven 10-shot strings before the software locks -- so then you have an interrupted string. It's not unusual to have the software lock in the 3rd or 4th string. And you may have to reboot your computer. If you only loaded 5 shots for a particular load values you may be screwed.

On the other hand, if I just leave the laptop in the car, I can pretty much count on the PVM-21 to register every shot that went through the rectangular "sweet spot" which is about about 4.5 in. x 8 in. (110 x 200mm).

I've talked to Werner Mehl (Kurzzeit.com) who invented the machine. He understands that people are unhappy with the software but he says the problems are all because of: a) operator error; or b) inherent problems with Windows. I've said, "OK, Werner... if the problem is the Windows OS, how come I can have a Canon printer/scanner/copier, running on a USB connection, that works flawlessly, and hasn't crashed once in over two years." His response was "OK, OK... I'll give you the code and you can spend the money to make it better." And he was being sincere -- he really believes the software is "good enough" and that PVM-21 sales are not sufficient to justify re-coding to enhance compatibilility with newer Operating systems (or to run the whole system with a USB). He really did offer to release the code to AccurateShooter.com.

Man, I would love it it I could simply plug the PVM-21 "white box" into a touchscreen PC tablet or iPad and power the whole thing off the tablet's USB port(s). But that's not going to happen anytime soon.

 

[6BRinNZ]

Is the PVM ok to shoot accuracy loads through or is the window too small for this purpose...i.e. with a harris bipod and a sand sack would I be ok to put a 10 or 20 shot string through it...I have learnt to check site line after every shot when doing this ...just wondering if the square window is asking too much? Given everyone plugs them now and again has anyone had to get parts for them?

Thanks

 

[Jay Christopherson]

There's really only three parts, not including screws: the first skyscreen, the second skyscreen, and the head unit. I shot out the second skyscreen on mine with a bow when I first got it (first shot through it in fact). I was able to get a replacement from NECO without an issue, other than the laughter which I accepted gracefully.

 

[Steve Blair]

The active window is 4½" X 8", fairly large. If the shot is within that window it will register. I have not shot it yet, so no parts.

 

[bozo699]

The active window is 4½" X 8", fairly large. If the shot is within that window it will register. I have not shot it yet, so no parts.

That will be a welcome site, the Pact II active window is about .0045" X .008"
Don't laugh I am not kidding, to get it to work at all I have cardboard cut outs that I stick in the screen's, the front one has a hole about the size of a dime and the back one has a black dot I put on it with the tip of a sharpie pen. then I put a bore sighter in the muzzle of the gun, when I get the laser dot PERFECTLY centered I carefully remove the cardboard cutouts then position the target in line of the rifle and chronograph, then plug the infrared unit in because it won't work even in the daylight with out it, if all the stars are lined up right and I cross my fingers and I don't use a muzzle brake it might work it only takes me about a hour to set it up and luckily I shoot at my house so I have power for the infrared : I sure will be happy when I get my PVM Oh by the way thanks for the help Steve.
Wayne,

 

[BoydAllen]

Wayne,
Yer doin' it backwards
Put the target where you want it. Set up the rifle so that it is secure on the bags, with the bolt out and aimed at the target. Get a little single LED flashlight, that is smaller than your bolt OD, and wrap it with tape so that it is a slide in fit in the action. Turn the light on and place it in the action, and then aim the rifle at the target, at the lowest place that you will be shooting at, centered. Then you position your sky screens by placing your head directly on the down range side, with your eye so that you are looking down the barrel at the light. Your eye will be where the bullet will cross the screens. While holding your position, adjust the position of the screens so that the line of the bullets flight is where you want it (relative to the screens). I have done this for years with just a reflective surface (something white) behind the rifle. The light is a recent addition. Using this technique you can set up by yourself, very precisely, where ever the target may be.

Boyd

 

[bozo699]

Boyd,
I have always in the past, when I was using beta chrony's used the exact method as you just described less the flash light and it worked great!! less then five minutes from the time you started taking the chrony out of the box till you were shooting. sometimes in lower light in the smaller calibers the white background was hard to see through the muzzle the flashlight is a great idea it wouldn't be precise enough for that piece of junk pact II but I will give it a try today with my old chrony. I realize now the less expensive chrony's and similar chronographs are not near precise enough for my needs,
I wouldn't have looked past the Oehlner 35 except I like to shoot at night, now that Paul,Jay, and Steve have got the lowdown pounded into my thick scull on the PVM-21 I am not so nervous (Thanks guy's) I have no problem spending money for my shooting sport (my wife will attest to that)
but I don't want to waste it either so I guess I was overly cautious since I have had several chronographs already that weren't up to standards. Anyway I appreciate the tip on the flashlight, great idea I will let you know what I think, take care.
Wayne.

 

[BoydAllen]

To show you how little I chronograph, I still use an old Oehler 33, that has the latest skyscreens, the same as are used on the 35. I don't mind writing down my results, and it works just fine.
Boyd

 

[Forum Boss]

First, these comments assume your scope is correctly sighted in.

We use a method similar to Boyd's, but with an in-chamber laser bore-sighter.

1. Aim rifle at 100-yard target with scope. Make sure gun is solid in bags so it can't move.

2. Tape a reversed target sheet or lightweight cardboard to the rear sky-screen.

3. Turn on in-chamber bore-sighter. Look for green (or red) laser dot on the paper.

4. Adjust chronograph height and angles accordingly.

WARNING -- don't use this method without the boresighter, because your scope is 1 - 2" above the bore!! AR guys with tall optics shoot their chrons all the time because they forget their scope is positioned much higher than their muzzles.

Another problem I see is that guys may line up their rifles over the chron successfully by visual boresighting, but their scope is adjusted wrong, or they proceed to move the gun to shoot a lower target. When chronographing -- keep the crosshairs on the level of the target you started with!

 

[bozo699]

My method I stated I use in post #28 is close enough to yours I feel confident I have at least been setting them up correctly, thank you Paul.
Wayne.

 

[BoydAllen]

If you get consistent readings, are able to shoot groups on targets at the same time, and have not hit your downrange equipment, you are definitely doing something right . ;D