Chronograph question.

[hereinaz]

^This. Every time i see someone on the internet claim they found single digit ES easy with their load my internal BS meter starts screaming. Getting single digit ES on a single 3 or 5 shot group doesn't make it a single digit ES load but that doesn't stop the internet claims. Single digit SD's is relatively uncommon too.

In the OP's case, at 500 yards i'm guessing a roughly 4" difference in elevation between the fastest and slowest speed clocked. If average is roughly in the middle you're talking 2" high or low from POA (less than a half MOA). That's a hit as long as other factors dont pull the bullet significantly further off course. I would be more worried about the Leupold CDS functioning correctly or the solution being accurate for the shot than I would that velocity spread inside 500 yards.

For me, stuff on the internet is assumed false to start with, lol.

 

[dieselchessy]

Per memory it would add 50%+ to the group sizes for the more sensitive bullets.

It’s one of those reloading rabbit hole things.
You either carry on ignorantly blissful, or you address it and move on.

Get to carried away and you’ll be turning necks, weight sorting brass and bullets, and uniforming meplats.

 

[N2TRKYS]

Per memory it would add 50%+ to the group sizes for the more sensitive bullets.

It’s one of those reloading rabbit hole things.
You either carry on ignorantly blissful, or you address it and move on.

Get to carried away and you’ll be turning necks, weight sorting brass and bullets, and uniforming meplats.

So, for a group size of say 2” at your desired distance with a 50% increase in group size, that would get you to a 3” group? Is that right or am I thinking about it wrong?

 

[Classyusa]

I guess in summation. What I have learned in this thread.

* My initial reaction to the ES of this load was due to my lack of experience shooting through a chronograph.

*The numbers are likely fairly accurate and the Caldwell chronograph , though not ideal, is a servicable unit.

* I gather that an ES like this is common with factory ammo and not alarming.

* From 406 Smith's data, the Federal/ Berger ammo shoots well out of his 7mmRM. (I will continue to test it through mine.)

* Be leery of my Leupold scope. (I don't want to sound like I am defending my equipment blindly but I have not been easy on this scope and it holds zero and has hit where is was dialed when asked to.)

My take on a lot of things shooting. There are a lot of solutions in a perfect world. Often what is thrown at us in actual field conditions or in daily life aren't perfect or ideal. Ammo is hard to come by, reloading supplies are hard to come by. Time to test dozens of factory loads or reload and develop a load for a rifle is hard to come by for many.

I have access to a good supply of these Federal's and I will gather as much data on how they shoot out of my rifle as I can and make a decision about hunting with them. In the mean time I will continue to improve my shooting technique and gather knowledge from kind and knowledgeable folks that are willing to share their insight.

I also have a Tikka T3X in .308 Win. I'm currently gathering data on how it handles Hornady ELD-M 168's. To hopefully mate it to a NF NXS or SHV. I will run some through the chrono and on to paper next weekend to see how the fly.

The ES of the 7mm had worried that my chrono was bad/faulty and I didn't want to waste anymore ammo if that was the case. I appreciate the input that it probably is not. I will proceed with the chrono testing of the 7mm Federals and the 308 Hornadys next weekend.

Thanks again.

 

[dieselchessy]

So, for a group size of say 2” at your desired distance with a 50% increase in group size, that would get you to a 3” group? Is that right or am I thinking about it wrong?

Your thinking of it correctly.

Also, for detail sake I measure the entire swing of the needle, not just half the swing.

 

[dieselchessy]

I guess in summation. What I have learned in this thread.

* My initial reaction to the ES of this load was due to my lack of experience shooting through a chronograph.

*The numbers are likely fairly accurate and the Caldwell chronograph , though not ideal, is a servicable unit.

* I gather that an ES like this is common with factory ammo and not alarming.

The ES of the 7mm had worried that my chrono was bad/faulty and I didn't want to waste anymore ammo if that was the case. I appreciate the input that it probably is not. I will proceed with the chrono testing of the 7mm Federals and the 308 Hornadys next weekend.

I've run a very similar Shooting Chrony for many years. Things I've learned.

Fairly sensitive to ambient light. Overcast Days or setting up under tree's can cause slow numbers.
Fairly sensitive to battery voltage. I keep the battery unplugged when not in use, and replace it often. Mine will start throwing odd numbers long before it flags for low Bat.
Fairly sensitive to muzzle blast. I keep mine a good 10' from magnums.

When mine goes wonky it tends to throw slow numbers.

I set mine up inline with a Oehler 35 and the numbers were very close.

 

[hereinaz]

I've run a very similar Shooting Chrony for many years. Things I've learned.

Fairly sensitive to ambient light. Overcast Days or setting up under tree's can cause slow numbers.
Fairly sensitive to battery voltage. I keep the battery unplugged when not in use, and replace it often. Mine will start throwing odd numbers long before it flags for low Bat.
Fairly sensitive to muzzle blast. I keep mine a good 10' from magnums.

When mine goes wonky it tends to throw slow numbers.

I set mine up inline with a Oehler 35 and the numbers were very close.

How close?

I ran a magetospeed and lab radar, they were the same, maybe varied up to two fps at most. It was so boring and I stopped after 50 rounds or so.

 

[N2TRKYS]

Your thinking of it correctly.

Also, for detail sake I measure the entire swing of the needle, not just half the swing.

Thanks. That wouldn’t be enough difference for my time to correct.

 

[Rich M]

I have a caldwell chrono and will say that it isn't a precision piece. Gives a good idea but that's it. Nice thing is that I can chrono every shot and work thru the data that way.

So if my rifle round is shooting 2,950 (243 100 gr NP) it'll vary into the 2,800 or 3,000 bracket from time to time but still shooting decently so I figure it is within the margin of error and the machine, not the bullet speed. For my uses it is "close enough". If the round is going all over the place and varying in speed, then I know it is the round and not the equipment.

Lab radar is what you need if you are gonna be real serious. I'm not there.

 

[Wrench]

Setup and environment is crucial with optical chronographs.

As for the Federal 168 Berger Hybrid, I only shoot paper out to 425 yards (further is just steel), but this is pretty typical.

(Initial zero & gathering of dope)
View attachment 266885

View attachment 266886

View attachment 266887

View attachment 266888

Adjusted Zero/Dope for the Federal:
View attachment 266889

What target is this? I have been wasting time without it.

 

[hereinaz]

I draw-up my own. Attached is the PDF of the 100 yard target if you want it. The other target is scaled at 425 yards because one of the ranges that I'm a member of is....special.

View attachment 267486

Prints on legal paper?

 

[Humboldt]

Your ES/SD is crap.
Could of been muzzle blast being only 6 or 7 feet from the chrono.
Also could be the rifle doesn’t like the ammo.
Or the ammo is just that inconsistent.
Most often I find factory ammo is 50 to 100 FPS slower than advertised, and ES/SD is poor 50-80fps range.
Out to 500 yards that 100fps ES could cause about 4” of vertical stringing with that load.
Most folks worry about the LOT numbers on the boxes more than the individual boxes the ammo comes out of.
If you have a dial made, it won’t work for elevation changes. And may not work for different ammo lot numbers. Them pre-marked for yardage dials are a crutch for folks just starting out. You’ll outgrow that pretty quick if you start shooting.

Your on the path. Chrono is a good move. Leupold with CDS dial (guessing) maybe not so much, but some folks like them.
A Kestrel would be a good move. The 2700 ($180) would do you well.
Sounds like you have an LRF.

This is somewhat reassuring. I have been handloading since I was a kid and my rifles group well but I never measured velocity until recently. I started using a Shooting Chrony and was shocked at the results!
My pet .308 loads were:
2921
2880
2888
2870

I know its s short string, but the spread is wide! Other strings showed the ES to be around 100 fps. Sounds like I should be a little more careful with how I set up the Chrony and I might get better results.

 

[hereinaz]

This is somewhat reassuring. I have been handloading since I was a kid and my rifles group well but I never measured velocity until recently. I started using a Shooting Chrony and was shocked at the results!
My pet .308 loads were:
2921
2880
2888
2870

I know its s short string, but the spread is wide! Other strings showed the ES to be around 100 fps. Sounds like I should be a little more careful with how I set up the Chrony and I might get better results.

You can load for groups, so you can tweak your process and load for velocity. Its just a few things that matter.