Help with ladder test results

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Help with ladder test results

#1 Postby pigdog » Sat Nov 03, 2018 8:40 pm


Was hoping to get some thoughts on these 2 ladder tests I did today. Rifle is a 6.5x47l 26 inch barrel, 12 power scope atlas bi pod and rear squeeze bag at 350m. Powder was reloder 16, 2 bullets tested were 139 scenars and 130 berger vld. Wind was from 3:30-4:00 average 5mph gusting to 10mph.

The vertical for both groups was 3.5inches. The scenars were seated 10 thou off and the Bergers were seated long and I let the bolt and lands seat them.

The scenars shot 3 and 4 (39.1, 39.4g) had quarter inch vertical and shots 6,7 (40, 40.3g) had no vertical should I shoot another ladder in between these charge weights do you think Maybe 5 shots each? My usual load for 139 scenars is 40g of ar 2209 which averages 2726 looks like reloder 16 adds around 75fps for equivalent charge weight.

The Berger vld is a bit more confusing to me I shoot with the magneto on all the time it doesn't change my groups just point of impact it hasn't let me down yet however as you can see shot 1 with the vld at 38.5g showed 2821fps the 38.8 went back to 2722fps so not sure if that was a misread or what but the target showed it as close to shot 2??

Anway shots 1,2,3 (38.5, 38.8, 39.1g) went into 1/2inch vertical. And shots 5,6,7 (39.7,40,40.3) went into 3/4inch vertical. Maybe load in between these and try a 5 shot each ladder?? I plan on doing the Berger seating depth test with these as the velocities seem a bit all over the place compared to the scenars

As a side note I don't know if many on here have seen the 10 shot saterlee load development basically you shoot a ladder without a target just looking for flat spots in the velocity between charge weight. Had I done that without a target the velocity flat spots in my data ARE NOT showing with small vertical it's actually the larger velocity difference in charges that is showing least vertical. My gut tells me to believe the target.

Anyway would love to hear some thoughts from you guys.
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Re: Help with ladder test results

#2 Postby saum2 » Sun Nov 04, 2018 9:27 am

Ok, I'll jump in, investigate loads around shots/loads 5 & 6 with the Bergers. Scenars 6 & 7

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Re: Help with ladder test results

#3 Postby bobped » Sun Nov 04, 2018 10:09 am

This is just an observation about what happens for me with a Magnetospeed Chronograph. I have one and use it a lot with load development, both with my own gear and other shooters that I do stuff for.
1. With the Magneto on it always changes my point of impact.
2. With the Magneto on it completely destroys the grouping ability of the barrel.
E.G. With the Magneto on my present .308 barrel my pet load gives a 1 inch group at 100yds.
Without the Magneto the same load consistently gives 1/4" groups.

I've repeated this sort of stuff a number of times on different barrels with basically the same results.
Now I use the Magneto for speed development but always take it off when I switch to group development.

Bob Pedersen

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Re: Help with ladder test results

#4 Postby pigdog » Sun Nov 04, 2018 12:48 pm

Thanks rebel 105 for the feedback.

Bob thanks for your feedback also. I haven't noticed the change in group size it did shift my zero up from memory. It may very well be that my equipment and my shooting abilities are too poor and are mixed in with noise but I haven't noticed such a large change in accuracy I will test this further no doubt.

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