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

[schmalts]

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.

Actually it is not the straight barrel that you are looking for. Let me explain. When you swing a baseball bat back and fourth and look at it in slow motion the spot that the bat is moving the slowest is that short dwell time of when you reverse directions to swing the other way. That short dwell time is much longer than the time the bat swings past the midway point (straight barrel) and when the the bat is swinging past the mid point it is moving faster as well. In theory if you have a velocity difference(bullet exit time) of 2% you would want that to happen in the spot where the swing is most motionless for the longest time. That spot is the turn around point and that is the max deflection in either direction. This is also why velocity has to be as tight between loads as possible.

 

[bluespruce]

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.

Out of curiosity, which one did you decide to go with?

 

[BuzzH]

Out of curiosity, which one did you decide to go with?

Varget.

 

[cahunter805]

I do the same as Schmalts and a few others. Velocity node and then fine tune seating depth at 300-500yards with 5-10 shot groups. I’ve seen a 1/2MOA 100 yard group go to heck at distance so prefer testing further.

 

[VikingsGuy]

I’ve seen a 1/2MOA 100 yard group go to heck at distance so prefer testing further.

Just a question, if a bullet is properly stabilized and there is zero wind, what could cause a bullet to change trajectory after 100y of travel? I can see a stabilization problem, and I can see a wind causing more effect over distance and creating a perception of lower precision, but not sure what law of physics would cause a bullet on a certain ballistic line from the barrel to 100y target to begin to change its angular direction mid flight. Similarly I have heard guys say a 2MOA load at 100y would tighten up to 1MOA at 200y. I don't understand how, once the trajectory has been determined, it varies except for wind effects and bullet instability.

I was talking with a long range guy who qualified for F-class US team who told me to always do my load development and zeroing at 100y (he even suggested 50y zero) to minimize wind effect on my data. Not saying he is right and you are wrong, just trying to understand and learn if I am missing something.

As aside, confirming "drop" over multiple distances is important, as published BCs aren't always correct, and some guys don't even have muzzle velocity out of thier own rifle.

 

[cahunter805]

Just a question, if a bullet is properly stabilized and there is zero wind, what could cause a bullet to change trajectory after 100y of travel? I can see a stabilization problem, and I can see a wind causing more effect over distance and creating a perception of lower precision, but not sure what law of physics would cause a bullet on a certain ballistic line from the barrel to 100y target to begin to change its angular direction mid flight. Similarly I have heard guys say a 2MOA load at 100y would tighten up to 1MOA at 200y. I don't understand how, once the trajectory has been determined, it varies except for wind effects and bullet instability.

I was talking with a long range guy who qualified for F-class US team who told me to always do my load development and zeroing at 100y (he even suggested 50y zero) to minimize wind effect on my data. Not saying he is right and you are wrong, just trying to understand and learn if I am missing something.

As aside, confirming "drop" over multiple distances is important, as published BCs aren't always correct, and some guys don't even have muzzle velocity out of thier own rifle.

I was speaking more to the traditional load 3-5 round type to determine powder charge. This style doesn’t take into account the ES and SD of a load. A 1/2MOA load at 100 with an ES of 50+ will most likely not be 1/2MOA at further distance under normal conditions.

I agree with shooting zero at 100 yards also. I run a 250 zero but shoot at 100 and adjust and shoot bullseye. Then dial my 250 zero and then rezero my turret. Then proceed to shoot long ranges and verify and correct as needed.

 

[noharleyyet]

Actually it is not the straight barrel that you are looking for. Let me explain. When you swing a baseball bat back and fourth and look at it in slow motion the spot that the bat is moving the slowest is that short dwell time of when you reverse directions to swing the other way. That short dwell time is much longer than the time the bat swings past the midway point (straight barrel) and when the the bat is swinging past the mid point it is moving faster as well. In theory if you have a velocity difference(bullet exit time) of 2% you would want that to happen in the spot where the swing is most motionless for the longest time. That spot is the turn around point and that is the max deflection in either direction. This is also why velocity has to be as tight between loads as possible.

Good grief....zzzzzzzzzzz

 

[JohnCushman]

I like 5 shots so you can compensate for a flyer in the group. Once I find a couple of strings I like, I'll go to 3 shot groups to find a winner.

 

[Deleted member 16014]

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.

This is more or less my process as well.

 

[VikingsGuy]

I was speaking more to the traditional load 3-5 round type to determine powder charge. This style doesn’t take into account the ES and SD of a load. A 1/2MOA load at 100 with an ES of 50+ will most likely not be 1/2MOA at further distance under normal conditions.

Thanks for the clarification - I agree. I was assuming decent velocity precision when I was responding. That's one nice thing about the velocity approach to loading - I would throw out a high fps ES/sd node mid development no matter how a few sets on paper looked. But with the exception of one frustrating 7mm08, fortunately I have always been able to find a load with SDs under 10, ES below 20 and MOA under 1.0 in fairly short order.

 

[Adam in Ohio]

I have always started with several loads based on reloading manuals, usually 0.5 gr apart. I then shoot 1 or 2 three shot groups with each. Then I do 5 shot groups to retest the powder charges that looked promising and were in the velocity range I am looking for.

I like @VikingsGuy's suggestion of the ladder test. I'm going to look into that a little more. I have always felt my method took way to many shots to narrow a load down, not that extra shooting is a bad thing...

 

[VikingsGuy]

I have always started with several loads based on reloading manuals, usually 0.5 gr apart. I then shoot 1 or 2 three shot groups with each. Then I do 5 shot groups to retest the powder charges that looked promising and were in the velocity range I am looking for.

I like @VikingsGuy's suggestion of the ladder test. I'm going to look into that a little more. I have always felt my method took way to many shots to narrow a load down, not that extra shooting is a bad thing...

Here is one of the early videos on the topic:

10 Round Load Development Ladder Test

www.65guys.com

 

[schmalts]

Good grief....zzzzzzzzzzz

I know... My brain hurts myself. But i guess it's keeping me employed so someone thinks it is valuable. Opinions vary though

 

[schmalts]

Here is one of the early videos on the topic:

10 Round Load Development Ladder Test

www.65guys.com

what's interesting is that it is a different way of doing the same thing I guess. What I have done is shot all rounds at 200-300 yards and they will string in somewhat of a line and then the flat spot was more determined by the 3 hits closest together of different powder charges. If is saw that 65.2. 65.5 and 65.8 were the closest of the 10 different charges I take the 65.5 as my starting load because it is the middle ground of the 3. The downside is the amount of time running back and fourth to mark each hit on the paper. this video way looks faster

 

[noharleyyet]

I set up the crono when I'm laddering fireformed loads....how anal is that. When speed and accuracy w/o pressure vectors, I'm getting close.

 

[44hunter45]

Here is one of the early videos on the topic:

10 Round Load Development Ladder Test

www.65guys.com

Great Article and video. Back in the day I think I burned half the life out of my 264WM barrel in load development. Less is more if you are shooting barrel burners.

 

[NVDesertHunter]

I have switched to ladder testing as well. I will load up 10 rounds starting at the min. and going a few grains above max. I shoot at a min. of 300yds but prefer 400yds and what for pressure signs after each shot.

will pick 3-4 loads that have the closest horizontal line then load 3 of each load and shoot again for groups at 200yds. Once I have my right powder load, ill start messing about with seating depth. Usually go through 30-50 rounds and 99% of the time have a round that shoots sub- MOA

 

[VikingsGuy]

I have switched to ladder testing as well. I will load up 10 rounds starting at the min. and going a few grains above max. I shoot at a min. of 300yds but prefer 400yds and what for pressure signs after each shot.

will pick 3-4 loads that have the closest horizontal line then load 3 of each load and shoot again for groups at 200yds. Once I have my right powder load, ill start messing about with seating depth. Usually go through 30-50 rounds and 99% of the time have a round that shoots sub- MOA

That is a very solid approach. For less experienced/less accurate shooters, shooters who have trouble finding low to no wind days or shooters who don't have access to ranges beyond 100y, using the newer chrono-based velocity ladder approach is a good option as it reduces the shooter and wind effects and works great at 100y.

 

[Brian in Montana]

I shoot strings of 3. If a load is NOT going to group you can tell in 3 shots. The ones that show promise, I'll shoot a couple more strings and get velocity data.

 

[Don Fischer]

I was speaking more to the traditional load 3-5 round type to determine powder charge. This style doesn’t take into account the ES and SD of a load. A 1/2MOA load at 100 with an ES of 50+ will most likely not be 1/2MOA at further distance under normal conditions.

I agree with shooting zero at 100 yards also. I run a 250 zero but shoot at 100 and adjust and shoot bullseye. Then dial my 250 zero and then rezero my turret. Then proceed to shoot long ranges and verify and correct as needed.

I suspect that cathunter is right. A 1/2MOA at 100yds may not be a 1/2 MOA at 500 yds But I also suspect the problem is not the load but rather the shooter. The farther away the target is the harder it is to hold the same hold!