Fiftydriver
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The reamer for my 257 Allen Magnum showed up Friday of last week so I got busy and chambered one of the fireforming barrels for this round because I had to see what the round looked like fireformed.
To be honest, they look pretty nice with that sharper shoulder and much fatter shoulder.
I measured the case capacity of the fireformed cases and it holds 123 gr of AA 8700 filled to the case mouth. This is compared to 104 for the 257 STW filled the same way and they both have a neck of around .250" so the AM is roughly 16% larger then the STW.
I have only used 8700 to date with the 130 gr pills out of the short 25" fireforming barrel but even with the short barrel and a powder that is a bit to slow for this bullet weight it is still topping the 257 STW when it is fired in a 27" barrel(three groove Lilja). I will be trying powders in the burn rate of Rl-25 and Retumbo. I like the looks of RamShots Magnum powder as it is said to have a burn rate very similiar to these other two powders but in a ball powder form which will be a bit easier on the throat.
I have not been able to post any pics on the new board so if some one could offer some insight into posting pics on this new sytem I will give you all a peak of this new hot rod.
Have a good one. One interesting thing, the 257 AM accepted up to 99.0 gr 8700 under the 130 gr BCFBHP for a velocity of 3400 fps in the 25" barrel. The 257 STW has been gaining about 50 fps per inch of barrel length above 26" so I feel the 3650 fps goal is well within range. Especially since the 257 STW was loaded with Retumbo which is much faster burning then 8700 or the likes.
The advantage with the 145, 150 and 160 gr pills should be even more dramatic as it will allow the use of these ultra slow burners with a more efficent burn under the heavier bullets. We shall see.
The Pac-Nore Super Match stainless 30" barrel showed up today. It is in a 1-8" twist for testing the 145 gr ULD and the 150 and 160 gr BCFBHPs. Got to get some other work done before I fit this barrel to an accurized 700 and see what this round will really do.
Anyway, any information on posting pics again would be great.
Good Shooting!!
Kirby Allen(50)
To be honest, they look pretty nice with that sharper shoulder and much fatter shoulder.
I measured the case capacity of the fireformed cases and it holds 123 gr of AA 8700 filled to the case mouth. This is compared to 104 for the 257 STW filled the same way and they both have a neck of around .250" so the AM is roughly 16% larger then the STW.
I have only used 8700 to date with the 130 gr pills out of the short 25" fireforming barrel but even with the short barrel and a powder that is a bit to slow for this bullet weight it is still topping the 257 STW when it is fired in a 27" barrel(three groove Lilja). I will be trying powders in the burn rate of Rl-25 and Retumbo. I like the looks of RamShots Magnum powder as it is said to have a burn rate very similiar to these other two powders but in a ball powder form which will be a bit easier on the throat.
I have not been able to post any pics on the new board so if some one could offer some insight into posting pics on this new sytem I will give you all a peak of this new hot rod.
Have a good one. One interesting thing, the 257 AM accepted up to 99.0 gr 8700 under the 130 gr BCFBHP for a velocity of 3400 fps in the 25" barrel. The 257 STW has been gaining about 50 fps per inch of barrel length above 26" so I feel the 3650 fps goal is well within range. Especially since the 257 STW was loaded with Retumbo which is much faster burning then 8700 or the likes.
The advantage with the 145, 150 and 160 gr pills should be even more dramatic as it will allow the use of these ultra slow burners with a more efficent burn under the heavier bullets. We shall see.
The Pac-Nore Super Match stainless 30" barrel showed up today. It is in a 1-8" twist for testing the 145 gr ULD and the 150 and 160 gr BCFBHPs. Got to get some other work done before I fit this barrel to an accurized 700 and see what this round will really do.
Anyway, any information on posting pics again would be great.
Good Shooting!!
Kirby Allen(50)