Hi everyone.

Bought a small sample pack of 6.5mm 127gr Barnes LRX to trial through my 6.5mm SAUM. Powder was Hodgon Retumbo, starting with 62.5 grs up to 64.5 grs.

This is the result of my testing at 100 yards

[URL= ]6.5 mm Barnes LRX [/URL]

What are the recommendations for developing a load based on the above?

I recommend adding 4 or 500 yards to make a ladder test

I would guess you pulled #2. If it were in a vertical line with the rest of them 1, 2, and 3 would be a pretty tight group.

It shows that changes with very slow powders don't make any difference at 100 yards.

quote:

Originally posted by ted thorn:
I recommend adding 4 or 500 yards to make a ladder test

This, although 4-500 yards might not be completely necessary, you need to use at least 2-300 yards to get enough dispersion for a ladder test to tell you anything.

100yds is just too close. I like 3-400yds. Maybe 200 I just dont have enough experience to say

More distance and more shots.....smaller increments in powder charges.......


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Similarly to what has already been said, I think I would load five at 63 or 63.5 and shoot them at 200. Looks to me like that is about the proper charge for that barrel.

When loading that volume of powder, .5grs is plenty until you start to really refine the load. Move back 100 yards or so and retry 1-2-3.

200 to 300 doesn't give enough flight time to accurately call this a ladder test

400 and beyond

It tells me that your best loading is #2...bang in the "middle" of loads #1 and #3. I'd ignore that that second shot if off to the left. Job done.

Too little data. Needs more shots, like me.

Did you get velocity data?

Usually ladder tests are run at long range to see if there's a cluster of loads that land in about the same place, even with different MV.

quote:

What are the recommendations for developing a load based on the above?

Repeat it with duplicates at 200 yards.

Ladders for me have generally only been much use if I make the charge increments smaller and get out a lot farther. The last one I ran was done in .2 increments over a 4 grain spread and was shot at 800.

Creighton Audette is generally credited with the idea.

Three shot groups at 200 with the powder charge increasing in .3gr increments.

I would not think one-shot groups prove much accuracy-wise.

A railgun in the Houston warehouse, maybe...

As I uunderstand the method is used to determine barrel harmonics and to find a node or grouping of powder increments that produce a bullet release point at the same vibrational point.

We know that a few tents of powder charge variation does not make for meaningful velocity/poi changes and our equipment is not capable of producing charges within less than a tenth +/- or so....

I use the method at 300 yards and found that with my NM M1 and 175 mks, 47.4 to 47.8 grns of 4064 produces a 1/2 MOA group.

I happen to use three targets and three sets of loads and fire them in order once at each target in succession, then move to the next increment, recording my call and the bullet impact as I go. It helps to have a KD range and a puller to track each impact as they are fired. 300 yds is a bit far to see and record bullet holes from the firing point by oneself, even with a good spotting scope ( mirage can render the target nothing but a blur at any magnification.

Once done with a new barrel, I never change the load specs until I rebarrel, then repeat. Load development is wasted barrel life and Krieger lasts about 4500 rounds and at $650 or so, it isn't cost effective to waste rounds other than in match conditions or proper practice.

Past 300 yds ad you wind up having to interpolate for wind effect too- not just lateral drift but precession/manges effect and the like making vertical changes that impact the assessment.

Kiwi

As suggested by other Forum members:

• Increase your distance to at least 200 yards, 300 is better
  
• Increase your powder charge disperision to 0.2 grains per increment
  
• Shoot early in the morning on a day that the weatherman predicts little or no wind
  
• Start with a clean barrel and shoot two foulers
  

You may have seen this article but if not it is a good overview
Long-Range Load Development

Let us know how you make out. Good luck.

Paul

Considering that the accuracy of the various dispensers and scales are only +/- .1gr, changing your load in .2 increments seems a waste of time and powder. You're looking for an accuracy node, and then you're looking for the center of the node.

Hey guys,

Many thanks for your advice. I have access to a 200m range that I can book for my own use. I think I'll try going up in 0.3gr increments.

I use 1/2 grain increments for my purposes with good results