Chrony question

[Dante231]

I've been reloading handgun for a few years. Just starting to do some rifle. I'd like to get a chronograph but I'm not really sure why. Does it matter how fast the bullet is travelling if it's accurate? What's the point of the speed, unless you're hunting and you need to know down-range ballistics?

On a rifle you're look for accuracy "nodes", from what I read on the interwebs. What if one of those nodes has a funky speed?

I guess what I'm asking . . . how do you use one of these - speed or accuracy? and which is priority?

 

[pastera]

If you are using published loads and aren't shooting long distance then a chronograph likely won't help much

I use mine to help match cast target loads to carry ammo.

Consistent speed is a precursor to accuracy - finding a consistent speed (low SD) that falls at a barrel node is the goal

 

[Compooky]

Don’t know why this is a question of either/or. Velocity is data. Use it however you need to.

Nodes are kind of like part tolerances. Get in the middle of a range so you’ll be fine if you’re off +/-.

 

[Dante231]

Let me reframe the question:

I bring my brand new chronograph out to the range along with my favorite rifle and a pile of reloads on the lower side of the recommended loadings. What do I do first?

 

[Compooky]

Let me reframe the question:

I bring my brand new chronograph out to the range along with my favorite rifle and a pile of reloads on the lower side of the recommended loadings. What do I do first?

Go home and load more ammo with a wide range of powder.

 

[groundscrapers]

I would be looking to use a chronograph to validate my reloads personally.

 

[paul73]

how do you use one of these - speed or accuracy? and which is priority?

you just need to read a bit about the process.
the target goal is the optimal combination of 3 sets of parameters - where you get an optimal speed, optimal accuracy/grouping and the stable ES/SD numbers.

es/sd - extreme spread and standard deviation is a derivative from measured speed and that will tell you what behavior to expect from your ammo at longer distances, as the amount of bullet drop directly derives from the fluctuation of initial speed your projectile had.

a more practical aspect - chrono also helps to make sure you not gonna blow up your gun when you run a ladder test getting loads close to the max.
Amazon product ASIN B07FTJYQ9ZView: https://www.amazon.com/gp/product/B07FTJYQ9Z

 

[Road_Clam]

I've been reloading handgun for a few years. Just starting to do some rifle. I'd like to get a chronograph but I'm not really sure why. Does it matter how fast the bullet is travelling if it's accurate? What's the point of the speed, unless you're hunting and you need to know down-range ballistics?

On a rifle you're look for accuracy "nodes", from what I read on the interwebs. What if one of those nodes has a funky speed?

I guess what I'm asking . . . how do you use one of these - speed or accuracy? and which is priority?

You're over-prioritizing "velocities" (i.e speed) . Velocities, along with SD's and ES's is cumulative data for YOUR barrel . Use the comparative veloicities along with observing your fired casing primers for over pressure signs. Use velocity and observed higher accuracy data to compare different bullet brands .

I learned that with my Rem 700 Varmint 308 that with a 168 gr FMJBT match bullet my consistient high accuracy node reguardless of bullet brand was about 2570 fps .

 

[whacko]

Let me reframe the question:

I bring my brand new chronograph out to the range along with my favorite rifle and a pile of reloads on the lower side of the recommended loadings. What do I do first?

First I'd bench rest and probably fire 5 each 3 shot groups at whatever distance your comfortable with and record the sizes if each group. If the groups suck......shit can the rest of the batch and head home. If they are "ok" groups I'd fire 10 through the chrono and record velocity for all 10. Now you have some data that may assist in tailoring that load. If your deviation is high think about things that can help get the rounds more consistent velocity. If the deviation seems good now you can work with the average velocity to see if that can improve the groups. You said you started at low end so.....go home.....bump the charge up and repeat.

 

[pastera]

Let me reframe the question:

I bring my brand new chronograph out to the range along with my favorite rifle and a pile of reloads on the lower side of the recommended loadings. What do I do first?

You run ladder loads over the chrono
10 rounds each from min to max
Start at min
Shoot, swap target and record the chrono data on the target.
Inspect each of the cases.
Move to the next higher powder charge.
Test ends where. You see pressure signs on the cases.

Smallest group wins followed by lowest SD

 

[Mark from MA]

You run ladder loads over the chrono
10 rounds each from min to max
Start at min
Shoot, swap target and record the chrono data on the target.
Inspect each of the cases.
Move to the next higher powder charge.
Test ends where. You see pressure signs on the cases.

Smallest group wins followed by lowest SD

This....and what Whacko said.....I ladder and pick best grouping loads first. Then I might break out the chrono.

Chrono helps you validate good loads.

The other reason for testing is I can remember when typical loads are not hot enough for some reason......

Case and point........ I had a .45 colt Henry and was trying to loads for hunting. Most factory loads were weak because they were made for colt single action type cowboy shit. I made some hotly loaded 250 grain hornady XTP rounds going at 44mag speeds of almost 2K fps. I had to work them up slowly and test them thru the chrono making sure the brass would hold up.

I use the chrono for archery as well, testing certain arrows for speed. But really dont need to anymore....I have arrows that work for hunting and stick with them. Speed is not everything in archery, if you use a light arrow it will not penetrate. And light arrows decrease your bow life and make your bow louder and vibrate more.

 

[paul73]

You run ladder loads over the chrono
10 rounds each from min to max
Start at min
Shoot, swap target and record the chrono data on the target.
Inspect each of the cases.
Move to the next higher powder charge.
Test ends where. You see pressure signs on the cases.

Smallest group wins followed by lowest SD

what also really matters in load development is the system of record, and how you keep your results.
the chrono i posted has an app - i use iphone version - and the app keeps all the results forever, which is very convenient.
and when i shoot my groups - either 5 or 10 rounds each, i use this target below from the 6mmBR.com - take a photo, and as i shoot them in order, i get data in the chrono, and then at home just type the data into the image, then store it. like one below:

 

[Dante231]

Thank you gents!

This was helpful. I needed to understand the relationship between speed, accuracy and consistency. I have my eye on the model posted, but it looks like I should try the ladder test first. Then put the chrony to use. And I will use it for arrows as well.

Any suggestions for reading on the subject?

 

[paul73]

Thank you gents!

This was helpful. I needed to understand the relationship between speed, accuracy and consistency. I have my eye on the model posted, but it looks like I should try the ladder test first. Then put the chrony to use. And I will use it for arrows as well.

Any suggestions for reading on the subject?

internet is your friend

Load Development - PrecisionRifleBlog.com

These are the posts related to load development.

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View: https://www.youtube.com/watch?v=BdyUalfj9qg


and many more.

ps. of my 2c or experience - i use a 5 shots ladder at 100yds when fishing for the specific 3 best nodes, then make a set of 2 - 3 loads 20 rounds each, then first do those groups of 10 at a 100yds, based on results then move to 300yds and then do a group of 10 there to see how it matches.

groups of 10 - because i am not a freaking william tell or pro competitor who can trust his groups of 3 to be representative - my arms bring enough uncertainty into results for a group of 10 to be needed. plus pro guys keep those test groups to be minimal to preserve the barrel.

 

[Dante231]

This video was really helpful. SD of velocity in tandem with accuracy, then refine with OAL. Thanks.

 

[paul73]

This video was really helpful. SD of velocity in tandem with accuracy, then refine with OAL. Thanks.

it is what i do, pretty much, and a good notion that minimal SD not always correlates with smallest groups.
and smallest group at a 100 not always correlates with a smallest group at 300.

but, overall, it is the process - first to find that SD/accuracy nodes, then play with seating depth to squeeze groups even more.

also, dunno what caliber you are into - look up info on this site, but, with a grain of salt as some loads posted there are way above safe max

6 & 6.5 Creedmoor Load Data – What The Pros Use

This past year I asked the 173 of the top-ranked precision rifle shooters in the country about the ...

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