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! 308 - 155 gr load and 708ai 180 gr load and corresponding projectiles .
5 shot group at 100 m shot of a Harris bipod . The high shot is me !
Last edited by plumbs7 on Wed Aug 26, 2015 7:50 pm, edited 1 time in total.
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.
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.
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?
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 !
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.
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.
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! 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?
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