ladder test help.....

[Ring]

distance 520yards

13 shots
243WSSM
start load

shot #1 = 37.5gr Varget
2=37.8
3=38.1
4=38.4
5=38.7
6=39
7=39.3
8=39.6
9=39.9
10=40.2
11=40.5
12=40.8
13=41.1

looking at this, i would say stay in the #4 ->#8 powder range?
am i right?

 

[jrw1976]

That is exactly how I read it as well. I would load up some groups in that powder range and keep testing.

Good Luck, Jason

 

[Bart B]

I don't think one shot per charge weight's enough to make a qualified decision on. The best commercial match ammo in a good rifle will hold 1/2 MOA at 600 yards with a 3/10ths grain spread in charge weight; with new unfired cases at that.

The best proof your one shot per charge test's a valid one is to repeat it. Then do it again. If the results for all three tests are the same, then you're inside the ball park between loads 4 and 8.

Finally, shoot one 20-shot group to get at least 80% probability that loads the best one.

 

[killahog]

Bart: I am new to using the ladder testing so could you explain what conclusion one could draw from shooting one 20 shot group. If only one group was fired what would the reloader use to base a comparision on.

 

[jrw1976]

Barts load development is probably terrific if you are a bench rest type shooter. But for us hunters using hunting rifles that method seems to me to be a waste of powder and bullets. But would be great for practicing shooting fundamentals, trigger time is always a good thing. The ladder test for us hunters works good because it helps us hunters save some money and time on load development so we can spend it in other areas.

Jason

 

[B-RAD]

I start with Rifle twist (1-14 twist) So I know I want a light bullet in .223 caliber, I come up with 40-50gr bullets through reading. I then go to Feet Per Second ex. 3300 - 3400fps is what range I want to shoot in. So I grab a reloading manual and simply find those ranges, I look each one up until I find a powder/bullet combo that gives me the fps I'm looking for ex. 26gr of H335 gives me about 3400fps with a 50gr bullet. I will then load that load at + and - .5gr and see which works best and then maybe take the best and go + or & .2gr to find the best load, I haven't had to go to the + & - .2gr yet, but it's comming.

Here are some examples links to a .pdf that should help
5 Shot Groups at 100yrds:
Cooper Load data <Link
AR-15 Load data <Link

Happy Reloading

Note: I don't believe in the ladder test, it's completely pointless, maybe if you shot 3 bullets of each to see what bullet/powder combo groups the best, after all thats what we are after, this one bullet crap isn't going to do anything but waste more money...

 

[killahog]

I think you you need a few more beers. Or maybe I do before I understand what the hell your talking about.

 

[B-RAD]

Yeah.... I needed another..

Anyways It's fixed now. gun)

 

[rscott5028]

I don't think BartB's comments are out of line or incongruent with the OP's analysis.

To BartB's point, one shot for each load only "seems" to imply that shots 4-8 may provide relatively tighter vertical spread than the outliers.

While the results hint at a trend, there's no assurance that repeating the test will result in the same conclusion. Nor that any of the loads in that range will produce the desired grouping.

The more samples you have and the more consistent the results, the better predictor of future performance.

You've made a great start. Don't settle too soon. Keep going.

-- richard

 

[Ring]

i just loaded up 3 each of 4 to 8... hoping i have time to test this week

 

[Bart B]

The best information on analysis of a shot group's found in this website:

Group Size Analysis

Simply overviewed, extreme spread's the worst and either mean radius or radial standard deviation's the best. This applies to finding the point in a ladder where a given load prints shot holes in elevation as well as what load produces the best accuracy.

For example, US military arsenals measure small arms ammo accuracy by mean radius. They shoot several dozen shots per test group. I've seen as many as 200 in a 600 yard group of 7.62 NATO ammo. Yup, 'tis hard to pinpoint the center of some of those holes in the middle of a 10-inch group of them, but the results are almost 100% reliable in assesing what the worst accuracy a given lot of ammo shoots.

Worst accuracy is always the best to claim for small arms ammunition. When one bases accuracy on the smallest group(s) shot, they're using a very tiny percentage of all groups/shots fired. Virtually all the others will shoot worse. Sometimes much worse.

Someone told me years ago to decide what accuracy level I wanted by defining what's the greatest distance I would accept missing my point of aim at the target's range. Then multiply that distance by two to get the worst accuracy that would meet my objectives. For example, if I wanted to miss a 500 yard point of aim by no more than 2 inches, I'd need a rifle and ammo that would shoot no worse than 4 inches at 500 yards; that's 8/10ths MOA. Statistacally speaking, that would require stuff that shot a mean radius at 500 yards of about 1.3 inches; that's a group average of about 2.6 inches.

 

[TOM H]

i just loaded up 3 each of 4 to 8... hoping i have time to test this week

This was posted by Bounty Hunter here 2009 might want to read it

Long-Range Load Development

 

[Mikecr]

By the time anyone satisfies Bart's lunacy with a HUNTING CARTRIDGE, they'll have no barrel left for field use..

 

[Tikkamike]

By the time anyone satisfies Bart's lunacy with a HUNTING CARTRIDGE, they'll have no barrel left for field use..

I dont know if its lunacy, I dont shoot 20 shot groups 5-10 shot groups usually tell me what I want, Basically what he is saying (i believe) is you want a large sample of shots. 1 shot tells you nothing, 2 or 3 doesnt tell you much either, what you are looking for is precision and repeatability. that 1 shot a piece target that was posted looks like it was used to pattern a shotgun and there is no information on it. you need to verify your data especially with a huge patern like that. i see no trend whatsoever.