Rifle load development methods compared

Nature Boy said:

All of that vertical could be your shooting set up (i.e., rear bag)

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MCMXI said:

Yeah, I think that was the problem. I bought a flat leather bag for the rear but haven't used it with the AXMC yet. I did use it with the AW and it worked very well.

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MCMXI said:

This morning I managed to do a 300 yard 10-shot test of the load shown in my last post using Federal GM205M primers. I shot off a concrete bench using an Atlas bipod up front and a rubber pad at the rear. I need to get a leather sand filled flat bag for the rear of this AXMC because I've struggled a bit with this stock. I'm fairly sure that the vertical deviation was due to me not controlling the rear of the rifle as well as I should have but left to right was excellent. Regardless, this load needs a bit more work but it's looking pretty good so far. I don't single load any rounds when shooting the AIs since they're practical rifles not designed for F-Class or Benchrest.

The range I shot at today doesn't have 110V power and the LabRadar goes through AA batteries in a hurry so I didn't get any velocity data. My comment re vertical error is mostly conjecture on my part based on my not being comfortable with the rear of the rifle. Velocity data would have been interesting though.

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MCMXI said:

The range I shot at today doesn't have 110V power and the LabRadar goes through AA batteries in a hurry so I didn't get any velocity data.

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lordpaxman said:

Get a power bank and you won't have to bother with AA's anymore. I got one like this but there are lots to choose from:
https://www.amazon.com/dp/B072XD7SDB/ref=dp_cerb_2
One other thing, the micro usb cable connection in to the Labradar is a bit touchy. I found muzzle blast was hitting the power cord and the lab radar would turn off. Either get a 90 degree micro usb or use some tape to insure there's no movement.

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South Prairie Jim said:

Protector sells an inexpensive front rest that works great with a basic rear bag, i use it especially for my hunting rifle it has a simple threaded post a lock ring $65 ish

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South Prairie Jim said:

I’ve always had difficulty developing a load using a bi pod.
Doesn’t bother some fellas but the vertical sure messes me up.

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Nature Boy said:

I’ve been curious how load development performed at 100 yards would stack up compared to the traditional ladder test shot at distance. Time and weather finally allowed me a window to get it done this morning.

Bottom line: both methods compared favorably to each other.

First, here’s the hundred yard load test a did a few weeks ago. This is my preferred method.

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You load 3 rounds each at increasing charge weights and shoot them in order (not round robin). To find the accuracy nodes you look for group centers that deviate the least from point of aim when compared to adjacent groups. Also, flat spots in FPS data should correlate to the node. My notes on the target indicate avg FPS on the left, charge weight on top, group center distance to POA on right and velocity change between charges underneath.

As the target above indicates, the node is between 30.7 - 31.0

Here are the same charge weights shot today at 500 yards in a more traditional ladder method (note: usually you shoot 3 at each charge but since I already had the data at 100 I only shot one each)

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Similar to the 100 yard test, charges from 30.7 to 31.0 change the least vertically.

To verify, I loaded 10 rounds at 30.8g and shot two 5 shot groups at 500 yards

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Both 5 shot groups are under 0.3 moa

I’ll finish with some more background on the complete load development process and some notes on equipment in a following post.

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