Hi everyone, I am new to this forum and am not sure if I am posting in the right area- please let me know if this belongs somewhere else.
Today I began load development via ladder testing for my new 308, originally owned by a gunsmith at Accurate Ordnance. It's built on a Remington 700 action with a 22" barrel. My hope is to be able to push out past 1K with this gun (and up to a mile, for fun, eventually
)
In the past I haven't been able to do ladder testing past 300 yards due to where I was located. Naturally this often led to inconclusive results. This summer I am out in Utah, and am able to shoot as far as the eye can see. Today I set up and carried out a Ladder Test at 600 yards and saw a clear and intuitive progression of hits up the paper (i.e., more powder charge=higher on paper). However, the distances between hits is what I am confused about and could use your help with.
From what I understand, barrel harmonics will manifest themselves on your target as "nodes" where adjacent loads fall closer together, indicating which loads fall at the top of a barrel oscillation (ie on the top of the sine curve that the muzzle traces while firing). I was under the impression that I would expect to see maybe one node, perhaps two. However, my results seem to show 5 nodes, 2 of which are especially tight. I'm wondering if this is a) because I tested over a large powder charge range, b) because my shorter 22" barrel is stiffer or something along those lines, or 3) I simply don't have enough data or I have bad data, and the nodes I'm seeing are imagined from scattered data points.
I'm hoping scenario a) is correct. Here is my test data:
New Lapua 308 brass
Varget Powder
WLR Primers
175gr SMKs
Loads were from 36.5 to 45gr Varget, in 0.5 grain intervals.
Here's the data graphed:
So, am I seeing a bunch of nodes here or is something else going on? Where would you recommend doing a second, refined ladder test?
I really appreciate the help!
Today I began load development via ladder testing for my new 308, originally owned by a gunsmith at Accurate Ordnance. It's built on a Remington 700 action with a 22" barrel. My hope is to be able to push out past 1K with this gun (and up to a mile, for fun, eventually
) In the past I haven't been able to do ladder testing past 300 yards due to where I was located. Naturally this often led to inconclusive results. This summer I am out in Utah, and am able to shoot as far as the eye can see. Today I set up and carried out a Ladder Test at 600 yards and saw a clear and intuitive progression of hits up the paper (i.e., more powder charge=higher on paper). However, the distances between hits is what I am confused about and could use your help with.
From what I understand, barrel harmonics will manifest themselves on your target as "nodes" where adjacent loads fall closer together, indicating which loads fall at the top of a barrel oscillation (ie on the top of the sine curve that the muzzle traces while firing). I was under the impression that I would expect to see maybe one node, perhaps two. However, my results seem to show 5 nodes, 2 of which are especially tight. I'm wondering if this is a) because I tested over a large powder charge range, b) because my shorter 22" barrel is stiffer or something along those lines, or 3) I simply don't have enough data or I have bad data, and the nodes I'm seeing are imagined from scattered data points.
I'm hoping scenario a) is correct. Here is my test data:
New Lapua 308 brass
Varget Powder
WLR Primers
175gr SMKs
Loads were from 36.5 to 45gr Varget, in 0.5 grain intervals.
Here's the data graphed:
So, am I seeing a bunch of nodes here or is something else going on? Where would you recommend doing a second, refined ladder test?
I really appreciate the help!
