Originally Posted by DragonsBane
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.
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.