These loads have shot very well in both my M70 & M700 8x57's

175gr Sierra
54gr Pro-2000MR
WLR
Nosler Case
2700-2740 (ft/sec)

170gr Hornady RN
48gr IMR 4064
WLR
Nosler Case
2600 (ft/sec)

150gr Hornady SP
48gr IMR4895
WLR
Nosler Case
2580 (ft/sec)

I do not remember the exact load but I had oustanding accuracy with 200 Partition and IMR 4350.

I use 54gr of H4350 with 200gr nos/par for 2550fps and 1 1/2" groups.
Also use 52gr of H4350 with 250gr woodleigh RN for 2300fps and 1" groups.

Most 8x57s have a 30-06 length box and if not its a simple matter to convert to a 06 length box..then load a dummy round with the bullet seated out as far as possible to get that extra powder capacity, then have the throat lengthened to allow that round to chamber..

This will give you a 8x57 IMP. without blowing out the shoulder and you can easily pick up about 200 FPS, same as Ackley but still shoot stand ammo..

The best powder I have found for the 8x57 is H414 hands down, it has 4350 burning rate but the case will allow more powder than 4350 thus increase velocity at equal pressure.