Ran some ladder tests today

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TexasMac
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Re: Ran some ladder tests today

Post by TexasMac »

I should mention that the above results are with the barrel resting on cross sticks at the location I've determined to be the "sweet spot". Also the bore was wiped between shots with a solution of water soluble oil and water. BTW, don't pay any attention to the position of the PJ Creedmoor patterns. I intentionally moved the sights down a bit to separate the patterns when shooting the 62.5gr load since the same target was used.

Wayne
NRA Life (Benefactor & President's Council) Member, TSRA Life Member, NSSF Member, Author & Publisher of the Browning BPCR book
http://www.texas-mac.com
bruce m
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Re: Ran some ladder tests today

Post by bruce m »

wayne
such testing reveals just how little it takes to deflect a bullet.
it is starting to happen even at 100 yds, but at 200 is becoming quite noticeable.
the so called creedmoor bullet load just happened to luck a more consistent condition.
those light winds at 6.00 or 12.00 can be very treacherous as any changes are all but impossible to pick.
hence the benefit of a higher b.c. bullet.
the recent thread about light weight bullets and charges for chickens might go hand in hand with this thread revealing deflection.
bruce.
ventum est amicus meus
TexasMac
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Re: Ran some ladder tests today

Post by TexasMac »

bruce m wrote: Mon May 18, 2020 11:50 pm wayne
such testing reveals just how little it takes to deflect a bullet.
it is starting to happen even at 100 yds, but at 200 is becoming quite noticeable.
the so called creedmoor bullet load just happened to luck a more consistent condition.
those light winds at 6.00 or 12.00 can be very treacherous as any changes are all but impossible to pick.
hence the benefit of a higher b.c. bullet.
the recent thread about light weight bullets and charges for chickens might go hand in hand with this thread revealing deflection.
bruce.
Bruce,

I'm confused about your comments. I certainly understand the benefits of a streamline high BC bullet. But understand the nice Creedmoor result was shot under the same wind conditions as the others including the Creedmoor load with the different powder charge. I can understand how/why cross wind changes may affect the horizontal spread but in all these tests there was only a slight tail wind.

Wayne
NRA Life (Benefactor & President's Council) Member, TSRA Life Member, NSSF Member, Author & Publisher of the Browning BPCR book
http://www.texas-mac.com
bruce m
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Joined: Tue Aug 04, 2009 5:25 am
Location: australia

Re: Ran some ladder tests today

Post by bruce m »

wayne,
those light tail winds, like all winds, are never consistent.
a 5.00/7.00 wind has less deflection than a 3.00/9.00 wind, but still has some.
it is not unreasonable to expect a perceived 6.00 o'clock wind to in fact be oscillating between 5.00 and 7.00.
at the very light speeds, this is virtually undetectable.
valdez might be able to pick it, but I can't.
but it will deflect a bullet sideways.
the amount at 200 yds is a surprise sometimes.
bruce.
ventum est amicus meus
Gamerancher
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Re: Ran some ladder tests today

Post by Gamerancher »

Wayne,
My .45-70 Browning/Winchester, that I use over there, likes that PJ Creedmoor bullet also. Last year, when I switched to using my CPA .45-90 for the scope matches, Aaron used my Browning with a borrowed scope and a bunch of scrounged ammo, my left overs from irons and some that John Gage gave us. There were three different powder charges from memory but all had that same bullet. With minimal time and ammo for sighting in before the match we got him a pig setting and went into the matches with that. He managed a 30 and 31 for his first scope matches.
The rifle/ bullet combination works well.
Out in western NSW where it don't rain much.
Australia
VectorMan
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Re: Ran some ladder tests today

Post by VectorMan »

Wayne, just out of curiosity, what lot number of Swiss powder are you using. The reason I ask is I had 2 different lot numbers of Swiss and one like compression and the other didn’t. Your groups with less compression show better groups. Wondering if your larger powder charges with more compression could benefit from less compression unless you can’t seat your bullet out any farther for chambering issues. Just a thought.
"keep adding powder til it bloodies your nose and blacks your eyes, then back it off bout 5 grains."
TexasMac
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Re: Ran some ladder tests today

Post by TexasMac »

VectorMan wrote: Wed May 20, 2020 6:19 am Wayne, just out of curiosity, what lot number of Swiss powder are you using. The reason I ask is I had 2 different lot numbers of Swiss and one like compression and the other didn’t. Your groups with less compression show better groups. Wondering if your larger powder charges with more compression could benefit from less compression unless you can’t seat your bullet out any farther for chambering issues. Just a thought.
I'm unable to give you a specific lot # since I purchased 3 cases of different lot #s a few years ago and mixed them all together. The lot #s are: 060.206, 120.312 & 300.112. This is my method to eliminate the changes from lot-to-lot. Although I don't believe there's sufficient data from the displayed groups to indicate a preference for lower compression I have found in general that as the compression exceeds 0.100" the groups tend to open up regardless of the bullet used or the load combination. I'm about to run out of this mixed lot and have another batch ready to use and mixed from 4 different lot #s.

BTW, COAL for all the loads had the nose firmly into the leade.

Wayne
NRA Life (Benefactor & President's Council) Member, TSRA Life Member, NSSF Member, Author & Publisher of the Browning BPCR book
http://www.texas-mac.com
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