Category: News

The following are the findings from shooting up to 100 shot groups, as per the following Hornady YouTube videos:

• https://www.youtube.com/watch?v=QwumAGRmz2I
• https://www.youtube.com/watch?v=6yZyXwy40JM

Taking these learnings here is a suggested approach for working up a load for ELR (Extreme Long Range):

• Seat your projectiles to a 25-30 thou jump and forget your seating die is adjustable
• For a given projectile load up 10 rounds for each suitable powder you can find
• Shoot a 10 shot group for each powder and look for promising candidates
• Explore those promising candidates with more 10 shot groups
• Use computer software such as OnTarget to calculate mean radius, and to combine targets together (shot in the same environmental conditions) to form 20 shot composite groups for your given projectile/powder combination
• If none of the powders look promising change your projectile, don’t faff around with powder charge weight or bullet jump
• When you’ve settled on a projectile/powder combination that works in your rifle system set your zero angle using a 10 or 20 shot composite group

Explain this crazy talk!

• Small sample sizes (3 and 5 shot groups), can sometimes tell you how bad something is, but can never tell you how good something is. They cannot be relied upon to give you accurate dispersion, velocity, or zero information.
• OCW (Optimal Charge Weight) and Velocity flat spots are mirages which are not repeatable and disappear when you fire 30/50/100 shots at each powder charge weight.
• Large changes in dispersion can be found by changing projectile/powder combinations
• Small changes in dispersion can be found by fiddling with powder charge weight and jump distance
• The higher the powder charge, the higher the velocity, the marginally higher the dispersion
• Standard Deviation figures can only be relied upon as a predictive tool if your sample size is big enough to form a normal distribution.  Anything less than 30 shots in your sample, you do not have a normal distribution and your SD’s are not useful as a predictive tool.

How variable is my dispersion for different samples sizes smarty pants?

As you increase sample size you funnel your dispersion values into a tighter and tighter band.  At some point you will reach a tight enough band to satisfy your expectations.

For example in this rifle system, 5 shot groups vary in size from 0.20 to 1.40 inches, all factors remaining the same.  Every gun will pull off a 5 shot quarter minute group if you shoot enough groups, but if you want to know what your system can consistently do, you need to shoot larger groups.

How far off is my rifle’s zero? 

If you zero with a 3 shot group, it can be a couple of clicks off in any direction.  At extreme long range, this zero error will lead to target misses.  A 10 shot group will get you closer, a 20 shot group closer still.

Those busterds just want me to buy more Hornady bullets!

Of course they do.

No one wants to shoot 30 shot groups for every change in a variable.  It’s not viable for many reasons including affordability, burning barrels etc.

However hopefully what they have learned, and shared, by burning up tens of thousands of rounds is give you the data you need to come up with a strategy for working up a good handload for your own ELR rifle system, with a good zero angle, to avoid making costly assumptions and adjustments with 3 and 5 shot groups.

The following information is for those engaging targets and/or animals at ranges far beyond what until relatively recently was considered consistently achievable.

As you stretch out to engage targets at 1000, 1500, 2000, 2500, 3000 yards it becomes critical to have precise inputs for your ballistic solver, and set a highly precise zero angle (not zero distance) for your rifle.

You are also stepping beyond the capabilities of traditional Ballistic Coefficient based ballistic solvers which take a limited number of inputs and base their calculations on a standard bullet profile which doesn’t sufficiently match the projectile you are using.

For a ballistic solver to return the correct dial up at long ranges it requires more input parameters than a BC based calculator, in conjunction with high resolution in-flight data for the actual projectile you are using.  An example of such a solver is Hornady’s 4DOF, which utilises doppler radar acquired data for several bullet manufacturer’s projectiles including its own.

What are the issues with setting a zero distance and using BC based solvers at very long ranges?

• a rifle’s zero distance changes with local environmental conditions.  If you’ve zeroed for 100 yards, in different conditions your zero distance will be less than or more than 100 yards.  This leads to errors that amplify at longer distances. Shooters using zero distance will often re-zero their rifle at a shooting venue prior to a match to align their zero distance with local environmental conditions.
• A BC based solver cannot provide sufficiently precise dial ups at longer distances.  As you push the range out the error exceeds the size of the target and you will consistently miss.  Shooters will then lie to the solver by changing inputs such as BC or muzzle velocity to get the rounds on target at that particular distance.  These lies need to be repeated at each distance engaged.

How do we address the above issues?

• use a solver that uses zero angle.  This is the angle between your scope and bore, and unless you fiddle with your rifle system never changes.
• use a solver that has a highly accurate model of your projectile’s trajectory.

In conjunction with environmental inputs, an accurate muzzle velocity, and several other inputs your solver will now give you a precise scope dial up.

Can you say “First round hits on target”?

Several aspects of reloading are influenced by statistical considerations, particularly in terms of achieving consistency and predicting performance. Here are some aspects of reloading that involve statistical considerations:

1. Velocity and Standard Deviation:
Velocity, or the speed at which a bullet travels down the barrel, is a crucial factor in ammunition performance. Reloading manuals often provide average velocities for specific loads, and reloaders use statistical measures, such as standard deviation, to assess the consistency of velocity across a batch of reloaded cartridges. A lower standard deviation indicates more consistent velocities, contributing to improved accuracy.

2. Group Dispersion and Accuracy:
When assessing the accuracy of reloaded ammunition, reloaders often measure the group dispersion, which refers to the spread of bullet impacts on a target. Statistical analysis of group sizes helps reloaders understand the consistency and precision of their loads. Smaller group sizes indicate greater accuracy and consistency.

3. Powder Charge Weight and Consistency:
The weight of the powder charge in a cartridge significantly affects ballistic performance. Reloaders aim for a consistent powder charge to ensure uniform pressure and velocity. Statistical analysis, such as measuring the standard deviation of powder charges, helps reloaders gauge the degree of consistency in their reloading process.

4. Bullet Weight and Uniformity:
Bullet weight consistency is critical for achieving predictable and reliable performance. Statistical analysis is applied to assess the uniformity of bullet weights within a batch. Deviations from the average weight can be measured to ensure a consistent ballistic performance.

5. Primer Performance and Ignition Consistency:
Primers play a crucial role in igniting the powder charge. Statistical analysis may be used to assess the consistency of primer ignition across a batch of reloaded ammunition. This includes measuring factors such as the velocity spread caused by variations in primer performance.

6. Case Dimensions and Case Neck Tension:
The dimensions of cartridge cases, especially the case neck, impact bullet seating and overall cartridge consistency. Statistical analysis is employed to measure case neck tension, ensuring that it remains consistent across a batch of reloaded ammunition.

7. Extreme Spread and Standard Deviation in Ballistic Measurements:
Extreme spread and standard deviation are statistical measures used to assess the variability in ballistic performance, including velocity and point of impact. Reloaders often use these metrics to evaluate the consistency of their loads and make adjustments to enhance performance.

8. Pressure Signs and Safety:
While not strictly statistical, the observation of pressure signs (e.g., flattened primers, ejector marks) involves assessing consistent patterns associated with pressure. Reloading manuals often provide guidelines on recognizing these signs, helping reloaders avoid over-pressure situations.

In summary, statistical considerations play a vital role in reloading, helping reloaders assess and improve the consistency and performance of their reloaded ammunition. By applying statistical analysis to various aspects of the reloading process, reloaders can make informed decisions to achieve optimal results in terms of accuracy, velocity, and overall reliability.

https://ffc.org.nz/?post_type=tribe_events

Our new member application processes have been updated to reflect legislative changes relating to the operation of firearms club ranges. Further changes may be required to ensure compliance.

The updated application form can be found here.

As per Pistol NZ’s recommendation our ranges will be closed during Level 3 & 4 Alert Levels.

I’ve had our contact details and blurb updated on the Destination Fiordland website.

An Events Calendar has been added to the website to make it easy to see when the monthly meetings, AGMs, shoots, and other events are scheduled. Fancy.

Click on the Events link in the Menu above or click here.