When testing new hunting loads how many rounds of each load?

[DRS]

When you're working up new hunting loads for a rifle how many rounds of each load do you make up? I have done 3 of each in the past.

 

[T Bone]

I do five. Lot's of right answers here.

 

[Rzrbck918]

I do five as well and I do it from a vice type rest to take as much operator error as possible.

 

[noharleyyet]

I do 3 of each.

 

[utah400elk]

I usually do three shot strings.

 

[VikingsGuy]

I have moved to "velocity ladder 10 bullet" approach. I make one bullet each of powder increments of 0.3gr (0.5gr for magnums) from max book load down 10 increments. I then start on the light end and shoot each over a chrono while watching for pressure signs as I go up. I then look at the resulting velocity plot to find one or two promising "flat spots" - suggesting loads which are somewhat load insensitive ("velocity nodes"). At these nodes I go by 0.1gr increments 2 loads above, 2 loads below and midpoint - I make 3x of each of these (15 bullets) and shoot over chrono looking for both low ES/sd velocity numbers and also low MOA on paper at 100y. If a node looks iffy, I drop it. If a node looks promising I pick the best load(s) and make 5x to confirm over velocity and paper.

When I first tried I wasn't sure if I trusted my loading process and did the velocity ladder 3x at each load, but after a few time through I was very comfortable that there was little noise in my loading process and that I could comfortably rely on the single bullet approach.

This process lets me get from no info to really solid round in 25-50 shots depending on whether I test one or two nodes and if either or both are worth confirming with 5x. If using for target rifle I would then play with seating depth to ekke out final improvements.

 

[MThuntr]

3 or 5 is pretty common. Often I'll start with 3 and then I start messing around with COAL or if I see something that is promising right of the bat I will build 5 more to confirm.

 

[VikingsGuy]

From a statistics stand point the question is with want confidence do you want to answer the question. If you are fine with - my three shot group was 0.9 MOA on paper, and I am fine if in fact it is anywhere between 0.7-1.3 MOA then 3x or 5x may be sufficient. But if you are saying load A is 0.90 MOA and load B is 1.05 MOA and I want to know which is in fact better you probably have to shoot a minimum of 10x and more likely close to 30x to truly answer. There are some good statistics articles on shooting at your google fingertips if you want to go down this rabbit hole. For hunting 3x is directionally fine, 5x is a little better, 8x actually helps quite a bit, but if you are trying to refine your loads and trying to ekke out every 0.1 MOA then most shooters do not actually fire enough rounds to make that choice with any actual mathematical certainty.

 

[VikingsGuy]

If you want a little math to go along with your loading strategy, I find these articles a good place to start:

Thinking statistically

Rifles are random number generators. Each time you pull the trigger, the bullet chooses a single outcome from infinite possibilities based on countless random factors. Without a time machine, you can...

www.autotrickler.com

Practical statistics for shooters

How many shots do you need to fire? How do you know if a result was just random luck? Have you given up on testing because it's too hard to make an improvement? All of these questions have answers....

www.autotrickler.com

 

[Deleted member 20812]

Those are good articles. For developing a load I’ll start with 3 shot groups. Final tuning is 5, and final proof is 10.

 

[BuzzH]

Never have been sure what to think of these pictures...all shot over a 2 day period, no change in zero from the same rifle while testing different loads.

It was tough to know which load to work with as they were all pretty good, interesting too the difference, or lack there-of, in POI between them without changing the zero.

 

[Don Fischer]

Asking about a hunting load? I use three to develop a load then five for practice shooting. Something I think is very true of hunter's, myself included, we're more shooter's than hunters. There is absolutely no need for a hunting rifle to do much better than 1 1/2" to 2" group's at 100 yds. If your a hunter, you don't take long shot's, you take sure shots! That said, if you develop with three shot's group's and never shoot five shot group's what does it matter. How many animals are gonna stand around and let you shoot much more that a couple shots at it? I think the best I ever heard about checking a load ws a storyabout a guy that went out every morning with his hunting rifle and fired one shot at a target! No real need to see a group otherthan to support your ego. The important thing is that first shot! With a hunting rifle of course!

 

[huntin24/7]

I wish I had the patience for a ladder test, but that will never happen. I usually start at max load and work back in 1/2 grain increments to about 3 grains or so in 3-4 shot groups. I’ll take the best group and try with different COAL and the same charge unless a load groups under 1 MOA. Then I’ll shoot another group with the same charge to verify the first group. Nice groups by the way buzz. That’s awefully impressive for a rifle to shoot so many different loads so consistently.

 

[Mallardsx2]

1/2 Grain increments starting at the min and going to the max with 3 shot groups.

I run 1 dry patch down the barrel between testing loads as well.

Good enough for me at this point in my life.

 

[Dan O]

Buzz it would be interesting to shoot these loads at 300 yards to see #1 group size and #2 the drop of each. Did you by chance have a chrono handy?
Dan

 

[Mtnhunter1]

Never have been sure what to think of these pictures...all shot over a 2 day period, no change in zero from the same rifle while testing different loads.

It was tough to know which load to work with as they were all pretty good, interesting too the difference, or lack there-of, in POI between them without changing the zero.

Just drives a shooter nuts......until you increase the distance! I'll usually back off to 200yds when this happens with my load development.....that guns a shooter for sure!

 

[noharleyyet]

Never have been sure what to think of these pictures...all shot over a 2 day period, no change in zero from the same rifle while testing different loads.

It was tough to know which load to work with as they were all pretty good, interesting too the difference, or lack there-of, in POI between them without changing the zero.

But you missed the damn quarter every time....

 

[BuzzH]

Buzz it would be interesting to shoot these loads at 300 yards to see #1 group size and #2 the drop of each. Did you by chance have a chrono handy?
Dan

I did not chrono until I settled on the load I wanted to use...

 

[VikingsGuy]

Never have been sure what to think of these pictures...all shot over a 2 day period, no change in zero from the same rifle while testing different loads.


It was tough to know which load to work with as they were all pretty good, interesting too the difference, or lack there-of, in POI between them without changing the zero.

The guy who started the "10 shot velocity" development thing has said, once he finds a velocity that works with a particular barrel/bullet combo, that he can change powders as he wishes and as long as it delivers the same velocity he gets very similar precision. Makes sense if load development is about finding a node in the barrel vibration where the bullet exits the muzzle when the barrel as close to straight as possible - similar velocity may correlate with barrel retention timing. But who knows.

 

[schmalts]

I have moved to "velocity ladder 10 bullet" approach. I make one bullet each of powder increments of 0.3gr (0.5gr for magnums) from max book load down 10 increments. I then start on the light end and shoot each over a chrono while watching for pressure signs as I go up. I then look at the resulting velocity plot to find one or two promising "flat spots" - suggesting loads which are somewhat load insensitive ("velocity nodes"). At these nodes I go by 0.1gr increments 2 loads above, 2 loads below and midpoint - I make 3x of each of these (15 bullets) and shoot over chrono looking for both low ES/sd velocity numbers and also low MOA on paper at 100y. If a node looks iffy, I drop it. If a node looks promising I pick the best load(s) and make 5x to confirm over velocity and paper.

When I first tried I wasn't sure if I trusted my loading process and did the velocity ladder 3x at each load, but after a few time through I was very comfortable that there was little noise in my loading process and that I could comfortably rely on the single bullet approach.

This process lets me get from no info to really solid round in 25-50 shots depending on whether I test one or two nodes and if either or both are worth confirming with 5x. If using for target rifle I would then play with seating depth to ekke out final improvements.

I do the same. Once I find the 3 closest shots of the string I load 5 of each and do a chrono/group test and make a decision on what I see. It takes a lot of time, and a lot of guys don't understand the process but it really is using science behind it because you want to time the bullet exiting the barrel at a certain dwell time as the barrel is moving from harmonics.