Unexpected Ladder Test Results

[PanaDP]

This is a continuation and companion of the testing I shot in this thread.

I shot a ladder test this morning at 300 yards and I'm having trouble figuring out what exactly is going on. The vertical dispersion is quite a lot less than I expected and everything is pulled out horizontally as it was on the windy side today.

Here's the target:

The numbers next to each hole refer to the load number, not the order in which they were shot. Those powder charges shot were:

1. 42.9gr Varget
2. 43.2gr
3. 43.5gr
4. 43.8gr
5. 44.1gr
6. 44.4gr
7. 44.7gr
8. 45.gr
9. 45.3gr
10. 45.6gr

Other than the powder charges, all variables are the same as in the original post I linked to: 178gr A-Max, federal brass, CCI200 primers, COAL of 2.825.

Any ideas? Numbers 3 and 4 are very close vertically but they aren't very near 2 or 5. Is it just that 3 and 4 are on the edges of a node? Load number 3 is the one that shot the tightest 100yd group in my previous test. Could the fact that load 7 has basically zero vertical dispersion be significant?

 

[turbo54]

Re: Unexpected Ladder Test Results

3 and 4 appear like a node, and show consistency string to string (good).

Same thing with 8 and 9, although there is a 9 flier. Still worth investigating.

If velocity is important - I'd OCW around 7.5-9.5. If not, 2.5-4.5 looks nice too.

 

[PanaDP]

Re: Unexpected Ladder Test Results

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">3 and 4 appear like a node, and show consistency string to string (good).

Same thing with 8 and 9, although there is a 9 flier. Still worth investigating.

If velocity is important - I'd OCW around 7.5-9.5. If not, 2.5-4.5 looks nice too.
</div></div>

Based on this advice

I shot 2 OCW strings today. One from 43.3 to 43.9 in .2 increments and one from 44.8 to 45.4 in .2 increments. These results are more in line with what I would expect. I think 45.2gr of varget (#7 below) is my OCW for this rifle.

 

[Rover31]

Re: Unexpected Ladder Test Results

Nice work
Try and repeat the 45.2 with a 5 shot group.
T

 

[vman]

Re: Unexpected Ladder Test Results

44.7 gr looks like a good place to start

Confirm it at 300 or further again with a 10 shot group. Take your time, see how it looks and if you do your part you should have a good indication on if it offers truly low vertical dispersion.

 

[Jeffvn]

Re: Unexpected Ladder Test Results

45.2 gives you the least vertical dispersion so far. I would try it at 300 or beyond with at least a 5 to 10 shot group.

Jeffvn

 

[MALLARD]

Re: Unexpected Ladder Test Results

how did you keep track of your impacts on your frist ladder test ?

 

[rcamuglia]

Re: Unexpected Ladder Test Results

You have a good rifle.

There is so little vertical that it's tough to tell. Any of the loads will shoot well. Shots 8,9 and 10 have the least vertical between them. Load 9 will probably be your best bet.

So, I would go one of two ways.

1. Pick the load with the highest velocity/least vertical(8,9,10) that shows no pressure and do a seating depth test. Try it at 100 and 600 shooting round robin groups

2. Re-shoot the ladder at a much longer distance, at least 600 yards, so that vertical can easily be identified, pick THE LOAD, and perform choice #1

good luck

 

[Runamuk]

Re: Unexpected Ladder Test Results

I'd have to try the 44.7gn load. Vertical looks good on that load and on both sides of it.

 

[rcamuglia]

Re: Unexpected Ladder Test Results

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Runamuk</div><div class="ubbcode-body">I'd have to try the 44.7gn load. Vertical looks good on that load and on both sides of it. </div></div>

Yep! That's a great load....for your competitors!

 

[bricktop]

Re: Unexpected Ladder Test Results

Try to pick up a chrono too and see how your velocity numbers are.

 

[PanaDP]

Re: Unexpected Ladder Test Results

I missed this question the first time 'round.

I shot at 300 yards so I could still make out hits by spotting scope. I plotted each hit as I shot it in a notebook at the bench. To double check myself, I colored each numbered load with a different color sharpie. That transferred well enough to the paper to see if the colors matched that I recorded were the same load.