Rifle load development methods compared

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Nature Boy

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I’ve been curious how load development performed at 100 yards would stack up compared to the traditional ladder test shot at distance. Time and weather finally allowed me a window to get it done this morning.

Bottom line: both methods compared favorably to each other.

First, here’s the hundred yard load test a did a few weeks ago. This is my preferred method.

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You load 3 rounds each at increasing charge weights and shoot them in order (not round robin). To find the accuracy nodes you look for group centers that deviate the least from point of aim when compared to adjacent groups. Also, flat spots in FPS data should correlate to the node. My notes on the target indicate avg FPS on the left, charge weight on top, group center distance to POA on right and velocity change between charges underneath.

As the target above indicates, the node is between 30.7 - 31.0

Here are the same charge weights shot today at 500 yards in a more traditional ladder method (note: usually you shoot 3 at each charge but since I already had the data at 100 I only shot one each)

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Similar to the 100 yard test, charges from 30.7 to 31.0 change the least vertically.

To verify, I loaded 10 rounds at 30.8g and shot two 5 shot groups at 500 yards

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Both 5 shot groups are under 0.3 moa

I’ll finish with some more background on the complete load development process and some notes on equipment in a following post.
 
I’m shooting a custom 6mm BR Ackley (6BRA) using 108g Berger BT Target bullets, set up in a prone position.

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Would this load data reveal anything meaningful if the rifle wasn’t capable of sub MOA accuracy? That’s a question that’s difficult to answer. Maybe not. I don’t know.

The same could be said for reloading equipment and how far you take the controlling of variables.

For instance, the things I do and don’t do.

I measure my powder charges to the 0.02g, or down to the kernel. I anneal after every firing

I don’t sort bullets by weight or BTO measurements. I take them as they come out of the box. I use Laupa brass and don’t weigh sort brass or de burr flash holes. I also don’t weigh sort primers

If I started doing some of those things would the results show improvement? Maybe.
 
I find it very interesting that the last two "good charges" printed nearly exactly the same, one ever so higher than the other from the faster speed.

I test in the same manner. Many times a good seating depth range will print the same shape groups, just higher or lower with velocity.

It is nice to know there are two good ways to arrive at the same station. Especially so since I am stuck at one hundred usually.

I ,too, do not sort bullets or cases. It always frustrates me when the mismatched ones shoot better...:)
 
I realize I’ve posted these in other threads but I should mention the total load testing process involves 3 steps.

1. Charge weight - finding the widest charge weight window that produces the least amount of vertical deviation (as defined in the first post)

2. Seating depth - to produce the smallest group spread at the charge weight determined in step 1.

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3 . Primer selection - the last step to fine tune the precision of load.

3ZbXUGV.jpg
 
Here’s the target data on the 5 shot groups.

2b0xaTY.png

QXZM2qt.png

I’ve been fighting horizontal variation in groups (shooter induced, not my crappy wind reading skills) so this is good data to track the results of changes I make. Biggest thing I’ve done is add more sand to the ears on my rear bag. As a result, I’ve cut my horizontal variation in half.
 
Bill
These are awesome “
You know I like your style of testing, I just wonder if you can get those to tighten up a bit with sorting BTO loading only those within .001 each session. And seating at 500 yards for a final tune.
I’d like to see a little 5 shots touching group
Jim
 
Concentricity, good match brass and bullets, good primers and consistent neck tension those are the same things I do.

Low SD and ES point to the best accuracy nodes FME.

My 100 yard sub 1/2 test load today using the 155gr Berger hybrids in my 308 had an ES of 13 and a SD of 5. Best numbers and best group of all of the test loads.

I have seen loads where they didn't match up but the shooter (me) or equipment were affecting the results that future testing proved my suspicions.

Anytime I am running a set of test loads with this particular rifle and a group ends up over 1.25" I know something is wrong.

I'm not a really good shooter and I know that the gun is more accurate than me and many of those sub half to 3/4" groups would be smaller if I were. Today is a good example of a sub half group that would have been a third" or better in the right hands. Bit I also know that I'm getting more use to this setup and would have been a 3/4" or larger last year.

Anyhow I have yet to ladder test for those same reasons. OCW works better for me in my abilities.

Yet to go prone with a proven load too but that's next on my list of goals to improving me, the biggest obstacle.

Nice setup BTW.
 
Here’s the target data on the 5 shot groups.

View attachment 842093

View attachment 842094

I’ve been fighting horizontal variation in groups (shooter induced, not my crappy wind reading skills) so this is good data to track the results of changes I make. Biggest thing I’ve done is add more sand to the ears on my rear bag. As a result, I’ve cut my horizontal variation in half.
is the gun touching the forend stop on the front rest? maybe pull it off a touch if it is.

luck,

murf
 
Does the Ballistics AE have the shot calculator like Ballistic X? Don't see it listed the reason I'm asking.

Nice info on the load development, nice shooting as always.

My range is still a swamp for 50 yrds. Even my original trail that runs beside it is flooded. My neighbor said he's got to add another 48" culvert pipe to keep from washing his road out. I showed him the video off my video camera showing the creek that's normally 4-5 wide when contained was 50' out. Looked like a raging river coming through my range. I went down to my 200 yrd bench and the soil had washed out behind the bench where the moles had tunneled, 1' deep. I need to shoot but handgun is the only range that is some what dry.
 
I went down to my 200 yrd bench and the soil had washed out behind the bench where the moles had tunneled, 1' deep
Bummer.

I can only shoot 100 yards (108 to the steel), but it is from one high spot across a natural drain to a hill with a lot more elevation behind that. It won't flood out.
 
Bummer.

I can only shoot 100 yards (108 to the steel), but it is from one high spot across a natural drain to a hill with a lot more elevation behind that. It won't flood out.

My 300 yrd range bench is still intact but some of the weeds/grass is getting high. I can not get my tractor through my swamp section to mow. The last time I tried (3 weeks ago) I though I was going to get it stuck. We have had over 9" of rain since then. May have to get the brush cutter out and knee high boots to cut it.
 
My 300 yrd range bench is still intact but some of the weeds/grass is getting high. I can not get my tractor through my swamp section to mow. The last time I tried (3 weeks ago) I though I was going to get it stuck. We have had over 9" of rain since then. May have to get the brush cutter out and knee high boots to cut it.

It's the same way in Oklahoma. I have hay that is ready to cut and standing water. My far target is hidden by hay, so I'm limited to steel at 130. It's sharpening my iron sight skills.

Nature boy, that's some impressive shooting. I've tried both ways, but prefer the ladder if I don't have a chronograph.
When I got one, it changed my outlook.
 
The shot calculator is what measures your shot pattern size, ak Ballistic-X. I was wondering if the AE version included it.

I see what you’re saying. They both calculate shot pattern size. Here’s both of them with the same target (my .308). You’ll note that there’s some variation between them. That’s the result of how precise you scale the target and place the shot markers. BallisticsAE has more data and Ballistics-X is easier to use and more for show and tell.

7TUZVSn.png

LraPXwe.jpg
 
I’d like to see a little 5 shots touching group

Oh Jim, I know......

10 years ago it was 5 shots in a paper plate. 5 years ago it was 5 shots touching at 100. Now it's 5 through the same hole at 100 and 5 touching at 500.

This might be a good time for a cautionary statement:

Kids, there is no bottom to the rabbit hole.
 
Thanks for the 'proving', Nature Boy. Your last comment about the paper plate reminds me of a range day in east Tx. A grandad, his son and grandson were out about 3 spots down. The grandson was shooting an iron sighted 30-30. When granddad announce it was 'good enough', they packed up and left. I looked at their target. Yep, paper plate at 100 yards with shots all over the plate (and many that missed - they went through 2 boxes of shells).
If I pick up a new rifle that can't do an inch or better at 100, I'm not satisfied at all.
 
I see what you’re saying. They both calculate shot pattern size. Here’s both of them with the same target (my .308). You’ll note that there’s some variation between them. That’s the result of how precise you scale the target and place the shot markers. BallisticsAE has more data and Ballistics-X is easier to use and more for show and tell.

View attachment 842331

View attachment 842332

Thanks for showing that they actually do the same thing on measuring group size. On the App store it does not mention or show anything on measuring group size.
The AE is on sale for $9.99 right now
 
Oh Jim, I know......

10 years ago it was 5 shots in a paper plate. 5 years ago it was 5 shots touching at 100. Now it's 5 through the same hole at 100 and 5 touching at 500.

This might be a good time for a cautionary statement:

Kids, there is no bottom to the rabbit hole.
Too Funny and so very true !
My bone head move is to go out and AGG 2.8 HG then figure it ain’t Small enough, so I’ll re tune AGAIN:feet:
 
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@Nature Boy, an excellent thread as usual. For many of us that don't have easy access to a 500 yard plus range it's good to know that a chronograph and 100 yard range can work just as well. I used the OCW "round robin" method for quite a few years, along with a chronograph, and it could be argued that your method at 100 yards is very similar since you're looking for a window in which the group center hardly changes, and the wider the window the better.

Do you have a similar data set for your .308 Win which shows the same three-step approach? It would be interesting to see a comparison between the two.

Out of interest, do you work up alternative loads using a different powder and/or primer as a back up?
 
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Do you have a similar data set for your .308 Win which shows the same three-step approach? It would be interesting to see a comparison between the two.

Yes, this was used to find my F Class load using 185 Berger Hybrids and H4895. 43.5g is a winner.

BD273A4A-A111-467B-B4E3-CDF175723131.jpg

Here’s the seating depth test i did with that load. I didn’t go further that touching the lands. Might run this again at some point with a few jammed to see what it does. As it is I seat at 0.000. -0.030 would also work.

B2135EC5-30F7-4671-8B54-B7C40C960813.jpg

Out of interest, do you work up alternative loads using a different powder and/or primer as a back up?

I do but usually out of necessity, like shortages of certain components. 6mm 108 Bergers were scarce for a few months and I tried the 107 SMKs. The node was lower and narrower.

vdSkNpb.jpg
 
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