7mm - 08 Ackley Improved information Blog!

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plumbs7
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7mm - 08 Ackley Improved information Blog!

#1 Postby plumbs7 » Wed Jul 08, 2015 7:17 pm

Hello there , I'm developing a load for 708 Ai . I'm a little stuck! 46 gr of 2209 have a a Fps of 2718 Fps. Ok sounded good . 46.8 of 2209 should get me in the 2770 fs with 180 hybreds . Well 5 shots got me 2735 Fps average with 2 shots the first and the last 2774 Fps .

Question ? If I left the 2209 in my chargemaster from last Sunday would this cause the powder to degrade and loss of speed?

Ok I've got some pictures that maybe of interest!
Image
308 - 155 gr load and 708ai 180 gr load and corresponding projectiles .

Image

5 shot group at 100 m shot of a Harris bipod . The high shot is me !
Image
Last edited by plumbs7 on Wed Aug 26, 2015 7:50 pm, edited 1 time in total.

plumbs7
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Re: 2209 Fps spread problems 708Ai

#2 Postby plumbs7 » Wed Jul 08, 2015 7:25 pm

Forgot to mention, using 308 lap brass and fed gold medal large rifle primers .
Thanks heaps Graham.

Brad Y
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Re: 2209 Fps spread problems 708Ai

#3 Postby Brad Y » Wed Jul 08, 2015 8:25 pm

Any chance the chargemaster over threw a charge? Or are you using them to throw then trickling up on another scale?

plumbs7
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Re: 2209 Fps spread problems 708Ai

#4 Postby plumbs7 » Wed Jul 08, 2015 8:34 pm

Hi Brad , no I've checked them on the chargemaster scale after the beep. I've been very lucky , it's proven itself to be accurate . So far ! Regards Graham.

plumbs7
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Re: 2209 Fps spread problems 708Ai

#5 Postby plumbs7 » Wed Jul 08, 2015 8:48 pm

Ok been chatting to Tony B (ecomeat) and others on another forum and may have the answers . Thanks . Kind regards Graham.

Norm
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Re: 2209 Fps spread problems 708Ai

#6 Postby Norm » Wed Jul 08, 2015 9:22 pm

Graham,

For comparison this is what I get with my 7-08ai and 32" barrel using (.308) Lapua LR primer brass.

180gn Berger Hybrid, AR2209, 46gn, Velocity 2715 fps.
180gn Berger Hybrid, AR2209, 47gn, Velocity 2776 fps.
180gn Berger Hybrid, AR2209, 47.5gn, Velocity 2782 fps.
180gn Berger Hybrid, AR2209, 48gn, Velocity 2813 fps.

plumbs7
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Re: 2209 Fps spread problems 708Ai

#7 Postby plumbs7 » Wed Jul 08, 2015 10:29 pm

Hi Norm , thanks that gives me something to work with! My Barrel is 30 " .

I just did a comparison between 7 mm hybred at 2735fps and 2820fps at 900 yds at 5 mph and it was under an inch and a quarter in drift ! 23.05 v 24.75.

plumbs7
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Re: 2209 Fps spread problems 708Ai

#8 Postby plumbs7 » Wed Jul 08, 2015 10:34 pm

I'll put some fresh 2209 and try again later on the week!

Brad Y
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Re: 2209 Fps spread problems 708Ai

#9 Postby Brad Y » Thu Jul 09, 2015 9:36 am

Graham you probably have it sorted but first thing I would be doing with random shots like that would be throwing each and every charge manually to see if I could get rid of the high/low velocity shots. Have you tried the palma brass necked down and CCI450's as well?

plumbs7
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Re: 2209 Fps spread problems 708Ai

#10 Postby plumbs7 » Thu Jul 09, 2015 10:49 am

No haven't tried Palma yet . But just having bit of a go in open , just locally . So no biggie . It took me 4 years to get a 308 win going . So it just takes time. Am trying to get the 7-08 going for Ipswich OPM . I'll keep you posted ! Thanks heaps every one !

plumbs7
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Re: 2209 Fps spread problems 708Ai

#11 Postby plumbs7 » Fri Jul 10, 2015 6:25 pm

Image

4 shot group at a 100m this arvo of a bipod too. Spread is getting better ! Very happy with the Bartlein!

I'll keep ya posted . Regards Graham.

RAVEN
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Re: 2209 Fps spread problems 708Ai

#12 Postby RAVEN » Fri Jul 10, 2015 10:14 pm

Plumbs
4 or 5 shots really does tell any thing much
Tuning a load is easy 20 shots and ya done.
Velocity variations can be any one or a combination of about 10 different things.

I would also shoot your groups at 300 it will give a better indication on its grouping potential and shoot a series of 5 shot groups with that same load and combine the velocities 10 plus shots is way better than 5 and 20 even more so

Try to achieve a SD in the single digit zone. And an average group in .3moa that is a comparative load.

RB :)

plumbs7
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Re: 2209 Fps spread problems 708Ai

#13 Postby plumbs7 » Fri Jul 10, 2015 10:56 pm

RAVEN wrote:Plumbs
4 or 5 shots really does tell any thing much
Tuning a load is easy 20 shots and ya done.
Velocity variations can be any one or a combination of about 10 different things.

I would also shoot your groups at 300 it will give a better indication on its grouping potential and shoot a series of 5 shot groups with that same load and combine the velocities 10 plus shots is way better than 5 and 20 even more so

Try to achieve a SD in the single digit zone. And an average group in .3moa that is a comparative load.

RB :)

Ok will do ! Thanks heaps ! Will let you know how it goes. Best wishes Graham Sells.

aaronraad
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Re: 2209 Fps spread problems 708Ai

#14 Postby aaronraad » Sat Jul 11, 2015 6:52 pm

plumbs7 wrote:Hello there , I'm developing a load for 708 Ai . I'm a little stuck! 46 gr of 2209 have a a Fps of 2718 Fps. Ok sounded good . 46.8 of 2209 should get me in the 2770 fs with 180 hybreds . Well 5 shots got me 2735 Fps average with 2 shots the first and the last 2774 Fps .

Question ? If I left the 2209 in my chargemaster from last Sunday would this cause the powder to degrade and loss of speed?

Ok I've got some pictures that maybe of interest!
Image
308 - 155 gr load and 708ai 180 gr load and corresponding projectiles .


Didn't notice it before on the facebook post, but is that jacket split on the 155gr projectile, or is that an optical illusion, or some background reflection?
Be careful what you aim for, you might hit it! Antipodean Industrial - Home of the G7L projectiles

plumbs7
Posts: 1124
Joined: Wed Feb 12, 2014 7:32 am
Location: Dalby/ Tara Rifle Club

Re: 2209 Fps spread problems 708Ai

#15 Postby plumbs7 » Sat Jul 11, 2015 10:28 pm

Hello Mr Raad ! No it's just the reflection of something elese mate . Cheers Graham.


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