Chronograph? Why do I need one?

[Thor357]

So I bought a chronograph, MagnetoSpeed V3. Now what do I use the data for?
I reload for .308 and .223/5.56.
Today I shot approx. 150 rounds of .308.
I had some phenomenal groups well under 1 MOA at 100 yrds and the chrono numbers were not good at all.
STD DEV's in the high 30's to low 40's'. ES' in the 40's-50's
And then I had some fantastic chrono numbers but the groups were horrible. STD DEV in the single to low double digits and ES' in the 5-7 range!
What's up with that?
Also tried some premium factory ammo and the numbers were all over the place and the groups were not nearly as good as most of my reloads.
Again, what's up with that.
How/why do I use a chrono to help me do.....what???

 

[Homerange]

1. It isn't hard to make better than factory loads.
2. A crony is your sanity check < where am I with what is possible with this load/rifle combo.
3. The holy grail is tiny groups at fast speeds (effective kills) with low ES. < With some effort achievable.
4, With a crony you will become a better handloader.

 

[dgeesaman]

In theory, you can use the chronograph to help develop an accurate long range load at short range. The load would have both good short range accuracy and low es. In practice, it doesn’t always work like that.

 

[Thor357]

1. It isn't hard to make better than factory loads.
2. A crony is your sanity check < where am I with what is possible with this load/rifle combo.
3. The holy grail is tiny groups at fast speeds (effective kills) with low ES. < With some effort achievable.
4, With a crony you will become a better handloader.

Yeah, I've quickly realized that I can usually make my own reloads out perform even the best factory ammo...usually.
I'm not sure I understand #2.
I'm strictly a target shooter so killing something "effectively" is not a priority. Getting small groups is my goal.
Why are low ES' necessary? I've had horrible ES' but the groups were sub-MOA.
Exactly how does a chrono make me a better handloader?

 

[Pres100]

Interesting that you ask the question of why you need one (chronograph) after you bought one.
Low ES numbers will have a beneficial impact when shooting over longer ranges. Not as big a factor at 100 yds unless you're measuring extremely small groups

Makes you a better handloader by understanding the impacts of the changes you make during the load development .. somehow I feel like you know these answers already....

 

[Thor357]

In theory, you can use the chronograph to help develop an accurate long range load at short range. The load would have both good short range accuracy and low es. In practice, it doesn’t always work like

So, for example, if I have great groups with lousy numbers, I could duplicate that load and expect similar results out to say 600+ yards?

 

[Bronsin]

Why are low ES' necessary? I've had horrible ES' but the groups were sub-MOA.

You won't have sub MOA groups at long range with horrible SD an ES numbers.

 

[Thor357]

Interesting that you ask the question of why you need one (chronograph) after you bought one.
Low ES numbers will have a beneficial impact when shooting over longer ranges. Not as big a factor at 100 yds unless you're measuring extremely small groups

Makes you a better handloader by understanding the impacts of the changes you make during the load development .. somehow I feel like you know these answers already....

In the interest of honesty and clarity, I've been using an optical chrono until this purchase.
As we all know, there are two kinds of people, those that shot their chrono and those who will. I did both!!!
My goal is long range shooting. I've had great success out to 600+ yards numerous occasions but not consistently. I do not have a highfalutin scale but the one I have is accurate and I know this because where I work I use precision instrumentation that requires calibration checks and my friend in the calibration department checked my scale and she said it is indeed accurate. With that being said, I do not allow
any variation in my charges. If I'm looking for, say 42 grains of Accurate 2460, I get 42 grains which means I will make adjustments until I get 42 grains...exactly. Despite being so OCD, I still occasionally see ES' shoot to the high side for no apparent reason.
My groups are typically sub-MOA (1/4"-1/2"). One of my goals is to put 5 shots through one hole. I've come close many times but not consistently.
As to whether or not I already know the answers? Hardly, I typically shoot 150-250 rounds per week because I'm in search of the "demon tweak" that will give me my goal. I'm close but I spend a lot of time and money dancing around the "perfect round".

 

[Thor357]

You won't have sub MOA groups at long range with horrible SD an ES numbers.

But I can have sub MOA groups at short range with horrible SD's and ES'?
If true. why?
If false, why?
Am I not asking the right questions?
Or am I just too stupid to understand?
Honest question, not hyperbole.

 

[Pres100]

In the interest of honesty and clarity, I've been using an optical chrono until this purchase.
As we all know, there are two kinds of people, those that shot their chrono and those who will. I did both!!!
My goal is long range shooting. I've had great success out to 600+ yards numerous occasions but not consistently. I do not have a highfalutin scale but the one I have is accurate and I know this because where I work I use precision instrumentation that requires calibration checks and my friend in the calibration department checked my scale and she said it is indeed accurate. With that being said, I do not allow
any variation in my charges. If I'm looking for, say 42 grains of Accurate 2460, I get 42 grains which means I will make adjustments until I get 42 grains...exactly. Despite being so OCD, I still occasionally see ES' shoot to the high side for no apparent reason.
My groups are typically sub-MOA (1/4"-1/2"). One of my goals is to put 5 shots through one hole. I've come close many times but not consistently.
As to whether or not I already know the answers? Hardly, I typically shoot 150-250 rounds per week because I'm in search of the "demon tweak" that will give me my goal. I'm close but I spend a lot of time and money dancing around the "perfect round".

While you need consistent powder charges for lower ES/ED, it's not the only contributing factor. If you're confident on the charge, then I'd look at neck tensions and brass for to the chamber as well as consistent case volumes and powder fills, annealing and so on....
There's a lot of other things as well that go into making consistent handloads.

 

[KMart]

A chronograph is a multiple use device. It detects bullet velocity and OCD level.

 

[Dimner]

It really depends on your goal. If your goal is shooting at 100 yards at moa, a chrono is not really necessary. If you are hunting deer out to 200 yards, probably not necessary. But if you shoot farther, how are you going to be able to hit anything without knowing the trajectory? Trajectory is very dependent on velocity. No chronograph no velocity data.

If you want to shrink your groups to 1/2 moa 90% of the time, a chronograph is a very useful tool. You could do it without one, but i suspect it would take you far more time, bullets, powder and primers.

The 2 best things a chronograph can tell you is why a load is not performing well and velocity so you can see when you are close to min or max pressure. The latter is important because most cartridges are designed to perform the best on the closer end of max pressure.

The groups you are seeing at 100 yards that are sub moa and st dev in the 30s-40s I would consider false positives. Especially with a barrel mounted chronograph.

 

[Dimner]

But I can have sub MOA groups at short range with horrible SD's and ES'?
If true. why?
If false, why?
Am I not asking the right questions?
Or am I just too stupid to understand?
Honest question, not hyperbole.

If you only shoot at short range, no chrono needed. A 30 cal bullet flight is forgiving at 100 yards if you are only looking for 1 inch center to center. I can do that with my savage 1899 takedown in 303 savage. Made in 1907. I can also do it in my 30-30 with bullets I have cast. There are 1000s of ways to get to 1 moa at 100 yards.

Keep in mind 1 moa is 6 inches center to center at 600 yards. To me, that's not acceptable, especially for hunting. And with std dev in the 40s, the trajectory table will show you at the very least that group is now 10 inches center to center.

 

[DLT]

Sounds like my luck with the damn things. More often than not I had the same experiences with many loads. I have even had good numbers and good groups only to take the magneto speed off and that magic load wasn’t so magic anymore. Talk about really pissing you off that will do it. Once you find a consistent load then chrono it for data

 

[DLT]

So, for example, if I have great groups with lousy numbers, I could duplicate that load and expect similar results out to say 600+ yards?

At 600 you will be fine with a E.S. of 20

 

[BartsBullets]

But I can have sub MOA groups at short range with horrible SD's and ES'?
If true. why?
If false, why?
Am I not asking the right questions?
Or am I just too stupid to understand?
Honest question, not hyperbole

Thor,

It all comes down to what matters for the type and distance of shooting you are doing. As someone who shoots competitive short and long range matches, I can tell you that what matters for one doesn't necessarily matter for the other.

At short range, you can have a high ES/SD and still shoot great groups. I have personally shot groups that measure in the zeros with a 40-foot ES at 100 yards. However, that same 40-foot difference will show up as a significant vertical deviation at long range. If you use a ballistic app or calculator, you will see the same thing.

Therefore, it's important to use your chronograph in conjunction with what your rifle is telling you on the target. For the most part, low ES/SDs are an indicator of how well you are reloading, NOT how well you are tuning. Your job is to get the gun shooting as accurately as possible with low ES/SDs. I personally want to see ES of 15 foot or less for long range.

Other uses for a Chronograph.

1 If you can’t obtain low ES numbers there either a problem with your reloading or the ignition system on your rifle.

2. Changing lots of powders. I just opened a new jug of powder for my 6PPC. It’s the same lot number but the burn rates are way different. I’m talking night and day. Without a chronograph I’d had no idea.

3. Learn your gun. I’ve used a labradar for probably 98 percent of my shooting sessions since they came on the market. If you pay attention you learn a few things. For example why is the first shot out of a clean barrel often low? Because is going significantly slower. It usually takes 1 to 3 shots to get it up to speed.

4. The same load, same gun same combination doesn’t always go the same speed for a given day. This is a big reason why a gun that shoots great today may not shoot that great tomorrow.

5. I don’t know what your set up is. But a good rest, rear bags and wind flags are a must for shooting small groups.

Bart

 

[CharlieNC]

STD DEV's in the high 30's to low 40's'. ES' in the 40's-50's

That doesn't jive. ES are much higher given those large SD which seem unbelievable.

 

[AlNyhus]

I have even had good numbers and good groups only to take the magneto speed off and that magic load wasn’t so magic anymore. Talk about really pissing you off that will do it.

It'd be more magical if accuracy wouldn't change after removing a weight from the end of the barrel. -Al

 

[Liven The Dream]

So I bought a chronograph, MagnetoSpeed V3. Now what do I use the data for?
I reload for .308 and .223/5.56.
Today I shot approx. 150 rounds of .308.
I had some phenomenal groups well under 1 MOA at 100 yrds and the chrono numbers were not good at all.
STD DEV's in the high 30's to low 40's'. ES' in the 40's-50's
And then I had some fantastic chrono numbers but the groups were horrible. STD DEV in the single to low double digits and ES' in the 5-7 range!
What's up with that?
Also tried some premium factory ammo and the numbers were all over the place and the groups were not nearly as good as most of my reloads.
Again, what's up with that.
How/why do I use a chrono to help me do.....what???

More than one post about shooting a V-3 on the Rifle and Good Numbers Poor Group ?
Some say get those good Numbers remove the V-3 shoot for Group ?

Have you tried shooting at 200 or 300 to see Groups ?

 

[Doom]

You can go down a rabbit hole in a hurry if not careful. @BartsBullets has given excellent advice. It's important to understand what your test data is actually telling you. Look at the post/ thread below.

What Kind of Std.Dev. is 'Reasonable'

For my 5.56 load, my SDs are around 10 fps. Here is my process: Decap Clean brass (brass is fully prepped – primer pockets uniformed (swaged, chamfered, etc.) firing pin holes chamfered I DO NOT ANNEAL – but do plan on starting on this but have not yet Full length resize (w/ std. de-capping...

forum.accurateshooter.com

Post #15