7mm - 08 Ackley Improved information Blog!

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watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#121 Postby watrob » Sun Jan 15, 2017 11:26 am

Did another days load development at Belmont Madden range yesterday. Was not real happy with the 7-08ai as it was throwing a flyer out every group. I had been running on the lower node and .015" jammed, a bolt push jam is .013". The load was 46.9gr 2209 using SR cci 450 magnum primers with 168gr Berger VLD's

I had shoot 48.0gr of 2209 before but groups were erratic, thus went to the lower node. Anyway I loaded up some cases with 48.0 grs 2209, seated this time at .010" jammed and went with SR BR4 primers instead. Temps were hot at 11:30am at Belmont Madden range around the 34 degrees with wind and mirage. I also loaded 47.8 and re-tested 46.9 with BR4 primers as well.

Shot this with the 48.0gr. Other changes I made where, different front rest bag (softer) with coarser grain sand, rubber around forearm stock return post on front of rest and brought post 25mm closer to front bag, believe this has removed some vibrations between front and rear bags.
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Quick
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Re: 7mm - 08 Ackley Improved information Blog!

#122 Postby Quick » Sun Jan 15, 2017 12:24 pm

Take it out to 300 to 500m and see how she goes.
Shaun aka 'Quick'
Yanchep, Western Australia

308 Win F/TR & F-S
7mm F-Open Shooter.

plumbs7
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Re: 7mm - 08 Ackley Improved information Blog!

#123 Postby plumbs7 » Sun Jan 15, 2017 5:13 pm

2860 fps seems to be the 168 gr short range node . The load I had at 300 yds Nats was this which was 48.0 gr of 2209 and fed large primer but was winter. I may have posted this before ? Not sure ?
But at 300 yds on the farm . Ignore the 2 sighters and the group of 10 shots went lower as it got darker!

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watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#124 Postby watrob » Sun Jan 15, 2017 11:04 pm

It seems that 48.0gr on average is the load, I am tempted to try SR 205m primers as they maybe the primer to use in the hotter months, the cci 450 mag primers I think are a little to hot, probably ok for winter but the 7-08ai is very touchy, 0.1 of a grain well maybe fine but 0.2 of a grain out and your off the node.

Norm
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Re: 7mm - 08 Ackley Improved information Blog!

#125 Postby Norm » Mon Jan 16, 2017 7:16 am

If you are finding that it is a bit touchy around the node. Try jumping them 30 to 60 thou and see if accuracy become more consistent.
This gives a softer launch and sometimes works with a finicky rifle and Berger VLD projectiles I have found.
But you still need to have the projectile bearing surface above the neck shoulder junction for best results. This can be hard to do with the short neck on the 7-08ai.

watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#126 Postby watrob » Mon Jan 16, 2017 9:37 am

Have tried a long jump but no good, also bullets are seated long, the pressure ring above the BT is seated above the neck shoulder in the case neck, have a .003" neck clearance to chamber. I am using Win Palma cases with sr primers so the cases are holding up ok with 48.0 grs.

I may try the SR Federal 205m primers as they are a little less hot and may give me smoother ignition in hot weather?

Steve N
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Re: 7mm - 08 Ackley Improved information Blog!

#127 Postby Steve N » Mon Jan 16, 2017 10:10 am

The Fed 205's are also softer material so don't be surprised if they show more pressure signs than the CCI 450's.

Steve.

Quick
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Re: 7mm - 08 Ackley Improved information Blog!

#128 Postby Quick » Mon Jan 16, 2017 10:36 am

Could be your barrel doesnt like 168gr VLD? Have you tried anything else?
Shaun aka 'Quick'
Yanchep, Western Australia

308 Win F/TR & F-S
7mm F-Open Shooter.

watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#129 Postby watrob » Mon Jan 16, 2017 3:40 pm

Quick wrote:Could be your barrel doesnt like 168gr VLD? Have you tried anything else?



It shoots one hole with 168gr Ber VLD's, it's just touchy on the powder load being right on 48.0 grs, jam has to be precise and neck tension the same with 3 thou clearance to neck chamber. I have a .310" neck chamber and load cases to .307"

As long as you have all the ducks lined up it shoots great, just means you have to prepare your loads carefully, any errors and you have a flyer.

Quick
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Re: 7mm - 08 Ackley Improved information Blog!

#130 Postby Quick » Mon Jan 16, 2017 4:15 pm

Just becauss it shoots one hole at 100yds doesnt mean it shoots good at lomg range. Id take it beyond 600m and see how it goes.
Shaun aka 'Quick'
Yanchep, Western Australia

308 Win F/TR & F-S
7mm F-Open Shooter.

watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#131 Postby watrob » Tue Jan 17, 2017 10:22 am

Quick wrote:Just becauss it shoots one hole at 100yds doesnt mean it shoots good at lomg range. Id take it beyond 600m and see how it goes.



Shot this at 500m a few weeks back but the wind got me on one round.
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Quick
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Re: 7mm - 08 Ackley Improved information Blog!

#132 Postby Quick » Tue Jan 17, 2017 10:27 am

Thats very very accurate. But how does it go at like 800m and beyond?
Shaun aka 'Quick'
Yanchep, Western Australia

308 Win F/TR & F-S
7mm F-Open Shooter.

mike H
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Re: 7mm - 08 Ackley Improved information Blog!

#133 Postby mike H » Tue Jan 17, 2017 11:01 am

Quick wrote:Thats very very accurate. But how does it go at like 800m and beyond?

You are putting the pressure on him,after all he is a Fly shooter and that stops at 500 metres.

watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#134 Postby watrob » Tue Jan 17, 2017 12:55 pm

mike H wrote:
Quick wrote:Thats very very accurate. But how does it go at like 800m and beyond?

You are putting the pressure on him,after all he is a Fly shooter and that stops at 500 metres.



I have a 7mm WSM which I will use for the longer distances with 180gr Ber VLD's

watrob
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Re: 7mm - 08 Ackley Improved information Blog!

#135 Postby watrob » Wed Feb 08, 2017 8:57 pm

I have decided after shooting some 450 rounds of the Lapua Win Palma (.308 fire formed to 7-08ai) SR cases to drop them. The reason is that these .308 cases have a coal of 2.015" and after 8 firings have not stretched, by the time I clean up the neck face it remains at 2.015". The 7-08 cases have a coal of 2.045", trimmed is 2.035", these Win Palma cases give me a void of some .030" in front of the case neck when chambered.

With the Win Palma cases and the bullet jammed at .010", the bullet jacket is I believe expanding in this void which is increasing the pressure and stability of the bullet, I have attached a photo showing what is happening.

15d95456-a24c-40a0-b240-f23a57f83d47_zpst4ofswqm.jpg
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