Chronograph?

[m00se]

How many of you check your loads on a chronograph? If you don't own a chronograph where can you go to use one?

 

[101VooDoo]

I do - chrono's are well worth the money.

 

[Chuck 100 yd]

I have had a Pact Pro for many years. Although I don`t use it that often,when working up new loads it will certainly be a big help.
In the before time (olden days), they were only kinda accurate and if you wanted an accurate unit you had to pay big bux for it. Now days the $100 units are very good and higher dollar units just have more features like remote readouts and printers. If you shoot at a public range,you will want the box with the printout to be on your bench so you don`t have to walk ahead of the shooting line after each shot or string of shots to read the results and reset the computer for the next string. The least expensive Shooting Croney(sp.?) has the readout screen on the unit out ahead of the firing line and in harms way. If my screens got shot on my pact,the computer part would still be ok and the sky screens are replaceable at less cost than replacing the whole thing.

 

[contender]

My Ohler 33P has been my best tool for testing my loads for years.

 

[Precision32]

I have an Ohler and a Chrony and both are a great addition to your reloading.

 

[WIL TERRY]

I've been using OEHLER [ AIL-er ] chronographs since the late '60's, a 10, a 33, and a 35P, and cannot imagine handloading ammunition without 'em. YOU are whistling on the wind if you think you know ANYTHING without a chronograph.

 

[Rclark]

I use the F1 Chrono. All you need is velocity . You can see the ES at a glance (Max - Min) after you shoot your string of 10+ rounds and look at the numbers. SD is about useless, but you can estimate it as 1/3 of ES . Of course Max and Min are obvious. Average is pretty easy to eye-ball too. Now when I get home I load the numbers into my spreadsheet and get the calculated numbers ... which pretty much match up with the quick field head calculations . Then add to my test load data spreadsheet for posterity and done for later reference.

I used to not check, but finally broke down and bought the chronograph a few years back. I think it was a good investment.

 

[Clovishound]

I used a chronograph for the first time about a month ago or so. I never really worried too much about my loads, I rarely load close to max, and pay attention to recoil and pressure signs.

I picked up some Power Pistol a little while back, and had nothing else to load 38 with. I loaded up some very conservative start rounds and was surprised at the recoil. I ran them over the chronograph, and found that they were right were they should be. It gave me confidence that these loads were safe in higher power loads working up from the minimum.

Where can I go to use one? I go to my buddy, he has one I can use whenever I want. Problem is I have to go to the outdoor public range to use it. Nearest one is an hour drive away.

 

[Rclark]

Of course average is not 'half way' between max and min... But 'usually' you see the shots hovering around a certain value. You know, 'humm looks like most are 1050 to 1055 range' with a few above and below... Doesn't have to be exact . As for SD, look at your accumulated data. You'll find 1/3 of ES is pretty close in most of your data. I've come to the conclusion that SD really isn't as important and ES. Low ES means you'll have a low SD.

The only way to get it { average } accurately is from a calculation of SD.

Ah, no, to get the average is to simply add up all your shots and divide by number of shots... That's the average.

 

[okie44]

Caldwell make a fairly inexpensive unit that you can plug into a smart device and control, save, edit, print and share data. Download the app for your device, plug it in with the provided cable and your in business. Here is an example.
Created: 04/12/14 12:32 PM
Description: 10" BFR 500 S&W 31gr W296 535gr Cast Rem large rifle primer
Notes 1: Mild Load
Notes 2:
Distance to Chrono(FT): 15.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 535.00
Temp: 86 °F
BP: 29.89 inHg
Shots:
# FPS / FT-LBS
5 1471 / 2571
4 1457 / 2522
3 1452 / 2505
2 1450 / 2498
1 1455 / 2515
Average: 1457.0 FPS
SD: 8.3 FPS
Min: 1450 FPS
Max: 1471 FPS
Spread: 21 FPS
Shot/sec: 0.1
True MV: 1459 FPS
Group Size (in): 0.00



Sent from my iPad

 

[Divernhunter]

My Ohler 33 is still working good after many years.

 

[Mobuck]

I've used a "Chrony" for several years and don't know how I got along w/o it before. Basically, I load using the Chrony to get the velocity I want/need while staying within the parameters of the manual data. At this point, I'm using a lot of "pulldown" military powder which may or may not perfectly match "suggested" data. By using actual velocities and watching primer signs(from known lots of primers), I can safely get to where I want to be.

 

[Rclark]

To say that SD is 1/3 of ES is an assumption.

Well, lets take a look .... (and yes, it is an 'assumption' by observation... not an absolute....)

.44 Special load

5.0g Bullseye, 240g SWC, 31 ES, 8 SD
5.5g Bullsee, 240g SWC, 23 ES, 5 SD
...
6.0g Unique, 240g SWC, 31 ES, 11 SD
6.5g Unique, 240g SWC, 42 ES, 12 SD
...
15g 2400, 240g SWC, 81 ES, 27 SD
17g 2400, 240g SWC, 42 ES, 11 SD
...
8.0g Power Pistol, 26 ES, 9 SD

I could go on for other calibers, but the results are the same (and I didn't cherry pick loads here either), 1/3 of ES is aprox SD. And this is over 10+ shots, usually 15+.

 

[mr surveyor]

since the ES and SD really have no meaning to me on the bench at the range, I find the inexpensive F1 Chrony with nothing but velocity display works fine. I have data sheets that I designed with the top section detailing the load data, the middle section for ten string velocity notation, then the bottom set up to note the HI, LO, and computed ES, SD, ME, etc. A simple spreadsheet program does all the calcs, and filling in the blanks on the data sheet gives me the opportunity to scrutinize the information a bit more.

At the range, I'm more concerned about the velocity .... and making sure I don't have a load going commando. Stats can wait.....

jd


edit to add: I look at it much the same as my profession .... we gather the data in the field, then analyze it in the office :wink:

 

[Rick Courtright]

My Ohler 33 is still working good after many years.

Hi,

Good machines! Mine's been going since about '82...

Rick C

 

[Rclark]

... the Unique charge was 6.0 grs. in both loads

Sorry about that. Fat fingered should be 6.0 and 6.5. Corrected.

I want to compare stats right then

. Understand. ES though you can see 'right now' by max - min (in your head) . You can write that down under your shot list. I don't use SD much as ES (to me) is much more important for consistency ... and of course if the load is actually 'accurate' on target ... that is THE most important.

 

[6GUNSONLY]

I've had access to one for years (my shooting buddy has one) and have used it frequently, but I'm about to buy one of my own. Not sure which one yet. I think they are an invaluable tool if you are really serious about your load development and performance.

 

[m00se]

Maybe if I'm really good this year Santa will put a chronograph under the tree It will be a while before I can pick up one of my own. Too darn many things take money... another pistol, an archery hunt, etc etc etc.

If anyone in the West Phoenix area wants to share their chronograph, let me know

 

[Iron Mike Golf]

Calculating SD from ES is exactly backwards. Even worse from small sample sizes.

About 68% will fall in the range of avg +/- SD. That's an ES of 2 times the SD.
About 95% will fall in the range of avg +/- 2 x SD. That's an ES of 4 times the SD.
About 99.7% will fall in the range of avg +/- 3 x SD. That's an ES of 6 times the SD.

Number of rounds you shoot matters. The SD the chrony spits out is an estimate. with 15 rds in the string, the estimated SD is within about 35% of the actual SD. That means your SD could actually be anywhere from half to twice the number on the chrony.

You can use all this to get a "worst case" estimate of ES using the SD from a 15 rd string. Worst case being the reported SD is at the extreme low end of the margin of error for that, meaning the actual SD of your ammo lot is twice what the chrony says. If you can live with a 95% confidence of ES based on SD, then that's 2 more SDs.

Handy rule of thumb for 15 rd string: Worst case ES = 4 x SD.
Handy rule of thumb for 50 rd string: Worst case ES = 3 x SD.

If you want to get to SD by using the measured ES, you need the ES from a string of about 750 rds.

 

[mr surveyor]

I still don't understand the need for instant gratification at the range. Standard Deviation is nothing but a statistical evaluation of a set of numerical data .... yes it has a value in determining the overall quality of a load, but are you going to change that load at the range, or are you going to start anew with a fresh loading you prepared at the home bench for range testing.

There are several free "spreadsheet" programs available to do all sorts of number crunching with input of basic data. Even the simplest allow input of bullet weight and individual velocities which gives in addition to HI, LO, ES, and SD, also ME and PF.

jd

 

[Rick Courtright]

There are several free "spreadsheet" programs available to do all sorts of number crunching with input of basic data. Even the simplest allow input of bullet weight and individual velocities which gives in addition to HI, LO, ES, and SD, also ME and PF.

Hi,

And in a worst case scenario, chances are if you're reading this forum on a computer, there's a spreadsheet program already in it! Most likely it's Excel from Microsoft, or the spreadsheet in the Open Office Suite from Apache (which does pretty much everything Excel does that most of us need, plus some others, like read all kinds of stuff Excel sometimes does and sometimes doesnt, and it's FREE!) Anyway, there's a "function" tool in both which allows one to set up a spreadsheet to automatically calculate all the "regular" results (Hi, Lo, Avg, ES, Sd) the chronos can do, plus you'll have to enter your own formula for ME and PF, but once you've written it, you can copy it forever.

If setting up a spreadsheet to do these things is baffling, you may know a computer nerd who can help you, or PM me and I'll see if there's some kind of a template in my collection of stuff I can share... (if you get a message my mailbox is full, please try again in a day or so!)

Rick C

 

[mr surveyor]

Rick ... yep, the "template" was what I referring to as being free. Generally Excell spreadsheet driven.


jd

 

[WESHOOT2]

I use a PACT One.
It (also) calculates ES and SD.
I gain load confidence by shooting and recording hundreds of rds, because statistics can be misleading......

 

[5of7]

I use a PACT One.
It (also) calculates ES and SD.
I gain load confidence by shooting and recording hundreds of rds, because statistics can be misleading......

I've used the pact model 1 for about 20 years. Record all the data on my computer along with accuracy data.

The Chronograph will let you know when you are reaching the ballistic parameters of a given cartridge and is invaluable when using a powder that you cannot find published data for, or in certain cases seating a bullet to a shorter than published OAL.

These things,(loading outside the manual) should not be done by the neophyte, but should be left to handloaders who have considerable experience in the craft. 8)

 

[Rick Courtright]

Thanks, Rick, I write with Open Office as well as MS Word and I didn't know that Open Office had that capability.
...
BTW, doesn't your Oehler 33 provide ES and SD stats? :wink:

Hi,

57K, doing the work in Open Office is pretty much like Excel, with slight differences in the syntax. It doesn't take anywhere near as long to do as it does to describe, but I'll try to point you there:

In an open spreadsheet, click on "Insert" on the toolbar at the top, then click "Function"
A "function wizard" should open up. Click on the "functions" tab at the top
You'll be presented with a "category" choice: you want "statistical"
A list of functions will pop up, and you can add the ones you like.

I find it's easier to just write the formula than plug things into the little pop up for the few functions I use frequently, but that's just personal choice. And I have to remember to write them correctly for Open Office or Excel depending on which one I'm using. For example, if I want the average of the numbers in the cells from A10 to A20, Excel would want to see "=avg(A10:A20)" while Open Office would want "=average(A10:A20)" but that stuff's easy enough to get used to.

As for the Oehler 33, the answer's yes: it gives five calculations: Hi, Lo, ES, Avg and Sd. But it's early '80s technology, so it doesn't store them or talk to a printer or computer, meaning each shot has to be recorded somewhere (on paper or electronically?) before it's overriden by the next one, and the calculations must be recorded before clearing the machine for the next string.

Rick C

 

[The Blackhawk Kid]

I have an F1 and it helps when testing new loads. Wouldn't be without one.

 

[6mm Remington]

I have a Pro Chrono which is nothing fancy but it works. It's an absolute must in working up accurate loads. Fun to use it at the same time.

 

[Dust in the wind]

I too have a pro chrony, have you ever wondered how accurate it is? Ever compare numbers with your buddies chrono ?

 

[6mm Remington]

I too have a pro chrony, have you ever wondered how accurate it is? Ever compare numbers with your buddies chrono ?

You know I really haven't. I did shoot some arrows through another chronograph at a range I went to and then later shot through mine and it was right in line with the other one, but those are pretty low speeds with the arrows. My recurve is shooting right at about 180 fps. I did find it interesting that I was able to chronograph a BB / Air Rifle through it! Those suckers are little.