257 Allen Magnum progress continues to another level...

[Fiftydriver]

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)

[robbor]

Didn't I see you post something about a 115 grain wildcat bullet, I have not been able to find the thread and richard has not gotten back to me yet. I have decided on a RUM based wildcat but still in the drooling stages, I will hopefully get the savage bought this next week.

[Fiftydriver]

The 115 gr Wildcat is just an idea at this time. We have to see how the 130 gr Wildcats do in this huge case first and then go from there.

SO at this time there is not a 115 gr Wildcat to my knowledge, just the 100 gr Bonded Core FBHP, the 120 gr and the 130 gr.

Good Shooting!!

Kirby Allen(50)

[Hired Gun]

[ QUOTE ]
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.

[/ QUOTE ]


First upload your pictures to a picture hosting site like http://www.imageshack.us/ or http://www.hunt101.com
Once they are hosted just copy and paste the image address to the text and make sure it has [img]....[/img] on the ends with no spaces. The periods are where the image address goes.

You can also use the image Instant UBB Code button down below and put you image address in the window that it opens.

I'd love to see that new 257AM.

[5Redman8]

Send the pic to me and I will post it.

Kyle
topboss8@yahoo.com

[Fiftydriver]

Well here goes.


This pic shows three fireformed and annealed 257 Allen Magnums loaded with the 130 gr BCFBHP with a 25-06 round on either side for comparision.


This pic compares the 257 Allen Mag with the next hottest round, the 257 STW. The fireformed 257 AM holds 16% more powder them the 257 STW. Currently, the 257 AM is matching the performance of the STW with the 130 gr BCFBHP bullets when the 257 STW is fired out of a 28" 3 groove Lilja at 3340 fps.

The 257 AM is getting this same velocity out of a 25" A&B fireforming barrel. In past tests the STW proved to produce about 47 fps more velocity per inch of barrel length. This will at least be true for the larger AM so 3600 fps with a 30" barrel should be well within reach and with the proper powder burn rate, I am hoping for 3650 fps.

The 257 STW will top out at 3450 fps with this bullet in a 30" barrel.


This pic shows the shoulder detail of the two rounds. Even though the 257 AM is 0.100" shorter then the 257 STW, it holds much more powder by use of a fatter shorter case.

Good Shooting!!

Kirby Allen(50)

[Sako7STW]

What is the parent case for your .257 AM? Looks to be a RUM case knecked to .257 and then improved????