7 x 57 ai

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by DragonsBane, Dec 10, 2009.

  1. DragonsBane

    DragonsBane Member

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    I have a couple of Mauser actions here from Brazilian 1908 Mausers. I am planning on getting a Shilen short chambered barrel from it from Brownells and chambering it to 7 x 57 Ackley Improved.

    I did some research and read an article that if a bullet with a coefficient of around .500 is used and shot between 2700 and 2850 fps then it will match the reticle on a mil-dot scope very closely.

    So the question is can I safely shoot the 180 grain Berger VLD at 2700 fps out of a 24 inch barrel ? I've run this through a couple of different ballistic calculators and come up with a pretty close result from each of them.

    At 1000 yards, this round still maintains almost 1000 ft-lbs, so it will be plenty for everything from Coues to Mule deer here in AZ. Should also work for elk out to about 600 yards.

    Any thoughts on this? Trying to get an effective round without having my shoulder tore off from recoil.
     
  2. elkaholic

    elkaholic Well-Known Member

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    You will probably get ALL kinds of "what's better" but for what you are trying to do, I think it would be a great round! Besides, if you are like me, it's kind of fun to have something a little different. Brass is plentiful, it should be a very efficient case, and ballistically not that far behind the very popular .280. Good luck with your project.....Rich:)
     

  3. TOM H

    TOM H Well-Known Member

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    If it was me I'd get a Broughton 5c,Kreiger 5r,Bartlein 5r,Rock 5r barrel 25" or longer and change caliber to a 284 you get the velocity plus that you want.

    I think the 7x57AI is a great caliber but has limits. Best I could do out of 7x57AI with a 24" barrel with 175gr bullets was 2711fps and that was pushing it.

    What I'd do is give Walt a call and see what he has to say. Good luck
     
  4. DragonsBane

    DragonsBane Member

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    Tom,

    I'm not building a high dollar rig here, just something to hunt with. I kinda just answered my own question with what I found on the .284 you suggested. I looked into the .284 and found that it is a real bear to get them to feed right in the mauser action. Can be done, just not for me right now.

    I found out that the F-class guys are pushing the 180 Gr VLD at and over 2950 FPS using Reloader 17. So according to what they are using 48.5 grains of Reloader 17 should put me right around 2700.

    The 7 x 57 AI case is a little larger than the .284 so it should be no problem. ANd being that the 7 x 57 is a long action, it shouldn't bve a problem seating the bullet out. With the extra room in the case 2900 to 3000 might be possible. Time will tell.
     
  5. Leathel

    Leathel Active Member

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    I have a 6.5-6mm Rem AI (basicly 6.5x57AI) and it out preforms a mates 6.5x284 with the same load his longer barrel gives a little less speed... my hunting load is tuned down (old action) to 3000fps with 140 amax's, great round, the 7mm will be the same , an efficent case:cool:
     
  6. TOM H

    TOM H Well-Known Member

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    DragonsBane, You asked this "Any thoughts on this?" I answer based on 2700fps with 180gr VLD bullet in a 7x57AI with a Shilen 24" barrel. The case capacity measure in water for the 284 is 64.59gr, 7x57 is 55.55gr,7x57AI is 61.44gr.

    If you look real close at the barrel on that F class 284 that gets 2950fps. The barrel is a 32" Broughton 5C. If that rifle didn't have that extra barrel length and being a 5c maybe high 2700fps. Here a deal from Broughton on the 5c barrels "Shooters are reporting more velocity, great accuracy, longer barrel life, reduced bolt pressure and ease in cleanability with the Broughton "5C ®" barrels. "

    Base on the fact that Shilen barrels threaded for the mauser are #2/3 contour I assume that you are building a hunting rifle that the reason I said at least 25" long barrel. If problem with the 284 case then go to a 280 case.

    Ackley data from Speer wildcat manual #4 published 1959 on the 7x57AI put his loading data @ 60Kpsi and that is the data I used in my 7x57AI.

    Don't get me wrong that I know all the answer you may be right. good luck on your project.
     
  7. DragonsBane

    DragonsBane Member

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    Tom,

    I think I'm going to take your advice and step up to a 280. After some research, it looks like my goal will be acheived alot easier with the .280 AI. ANd I will still have some room to grow at a later date. RL25 seems to work best in a 24 inch barrel.

    I found a post from a guy who is big time into the Ackley's. He has a 30-06 AI moving a 180 grain at 3000 fps with 66 grains of RL25. Now it would seem that 2700 fps would be easily acheivable with a similar load even in a standard .280. The only problem with the 06 load is that it is a max load and beats up primer pockets.

    So it looks like its a .280 or a .280 AI.

    Thanks everyone for the help.

    BTW, I found out that I will need about 32 MOA to get to 1000 yards with this cartridge. So a Bushnell 4200 with a 20 MOA base will work out just fine.
     
  8. royinidaho

    royinidaho Writers Guild

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    The only input that I have that may be relevant is that when, in 1966 I picked up a 1908 Brazilian Mauser in 7x57 the barrel was a dud.

    I then suggested a 270 Win to the smith. He took the action to the UPRR shops and determined that it Rockwell'd well with in specs.

    Its on its 2nd barrel and runs 140s near 3200 or more.

    I think she'll hold together.

    That rifle has been a family goto rig for nearly two generations.
     
  9. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    The 7x57 AI is an extremely accurate and efficient cartridge. Now that you are looking at the 280 AI I would also suggest the 7mm JRS. It is all you can get out of a 280 remington case and will virually duplicate the 7mm rem mag. I have the 280 AI, 7mm Gibbs and 7mm JRS all based off that size case. I have had the best results with the 7 mm JRS. It is a pleasure to shoot. But the 7x57 ai is also, just not quite as powerful.