Harmonics/Accuracy Nodes

dpollard

New member
How many of you pay attention to harmonics/accuracy nodes when working up a load for a rifle (optimal charge weight, ladder test etc...)?

Are these methods substantially better at finding a good load for a rifle in lieu of loading up 3 or 5 rounds and shooting groups at 100?
 
I played with the OCW/Ladder process several years ago and never could get it to make sense for me and my needs...

It is much faster for me to find really accurate loads in both a bolt action and an AR (.223) by loading in .1gr increments, starting at one full grain below reputable published max loads and working up to max +/- depending on pressure signs...In most cases, my best accuracy nodes fall between .4 and .7gr below max...

I've never been one to push envelops on speed, preferring repeatable accuracy over speed...

While my process may seem a little component heavy by some, I load ten rounds of each powder charge and fire the first five for groups, looking for those that show the most promise...If I find one or two groups, I will use the second five for verification of the first five...The rest I take back and tear down to reuse the components...The following targets are what I consider 'acceptable' groups at 100 yards...These were both in .223 AR, building loads for a Prairie Dog shoot...



The "Hot Case" note on the bottom target was when the brass from round #3 landed in the crook of my elbow just as I was tripping the trigger on shot #4 and I 'flinched' slightly...
 
I will place several targets in a horizontal line and shoot five shots at each one with a different charge weight. In accurate rifles, it is clear that some of the charge weights group together. I just did this for fun with a 223 and some 55 varmaggedons. From 24.4-24.9 grains there was a clear horiztal " streak " in there. I loaded a few more at 24.7 with different seating depths. They all shot under half an inch, and some under 3/8". It is a comfortable load with room for error.

This isn't the only way to do it. Robert Hoppes shoots 2 or 3 shot groups at 100 yards, takes the best load and tunes it at 600. I think his accomplishments speak for themselves.
 
Thank you for the replies thus far. Here is where I am at and what prompted my question. I have been reloading for about 5 years. As mentioned in my OP I generally load 3 or 5 rounds of the same charge weight covering the spread of published min/max load data in .3 or .5 grain increments and shoot groups at 100 yards and pick the best one or two, refine the powder charge a little more, shoot more groups, pick the one I like then try to confirm it with a 10 round group.

Lately I have thought it would be cool to try a more "advanced" loading method trying to (over)analyze what the bullets and barrel are telling me based on hits on the target. I say "(over)analyze" because I admit I do not understand the physics/science behind all of this so the jury is still out in my mind if all of this is worth the trouble and if the load/barrel harmonics etc...actually tell me anything.

I did a ladder test over the weekend at 550 yards with my .260 Remington. I loaded up 1 round at each powder charge from min to .1 over max in .3 grain increments. I know this is not exactly what you do in a ladder test but read this method on a reputable forum. I took the range of hits that had the least amount of vertical dispersion and bracketed loads around them and re-shot at 100 yards in 3 shot groups. The target below are the results of the 100 yard shooting.

In the past I would have taken 37.6 and called it good. In (over)analyzing I did not like that at .3 grains above this charge the group opened up a lot (37.9). When I look at 38.2 and 38.5 the groups are almost twins in terms of how they grouped on the target, which suggests to me perhaps this is a more stable powder range for this load combo. and warrants further testing with finer powder charges and playing around with seating depth.

Thoughts? Is there real science behind this or not?

If it is important to the discussion here is the load info:
.264" Lapua Scenar 139 gr
IMR 4451 Powder
Federal Match Primers
Seated .020" off the lands
26" Criterion barrel
Lapua Brass


 
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Quote: loaded up 1 round at each powder charge from min to .1 over max in .3 grain increments. I know this is not exactly what you do in a ladder test but read this method on a reputable forum. I took the range of hits that had the least amount of vertical dispersion and bracketed loads around them and re-shot at 100 yards in 3 shot groups.

This is actually Creighton Audett's original ladder method and it works for me. Not sure I understand how you arrived at the 100 yd loads, but it you pick the 500 yd. nodes that grouped the best and load in the middle, you should have the point at which +/- .1 or .2gr will affect POI very little if any.

I sure wouldn't give up on that 37.6 gr. load just yet.
wink.gif


Regards,
hm
 
I will do ladder tests at the max distance I would use the load. For hunting rifles that is 450 yards. Find where the 'rungs' in the ladder are not climbing much on the target, despite powder charge increasing in 1% of capacity increments. I will usually shoot 3 ladders and then retest the most promising load at 100/200/300/450 and then do a seating depth test on the load with the best results
 
It sure looks to me like every load on the target shot about the same POI, with the bottom three a little more consistent. I'd try tweaking that 38.5 load.
 
I agree with working on the 38.5. Try adjusting the seating depth. Also, when you're reaching out to longer ranges, neck tension and neck length will really show an effect.

I've use the OCW for years and it works for me. Since I've gotten into long range shooting, I do the ladder tests at 600 yds. and look for vertical dispersion as you do. One quickly learns that a tight group at 100 yds doesn't always translate to one at 1000 yds.
 
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