8x57 JS Looking for load data

sneaky pete · January 16, 2007, 05:17 PM

I've got a m-48 Yugo in unissued condition and am looking for load data for 180 gr Nosler Ballistic tip .323 bullets. I have the following powder availiable. IMR 4895, Vagret, VihtaVouri N-560 and a little bit of RL-19. I'll primarilly be using this round for killing boars/hogs, but some deer also. The Yugo has a 2.5x8 leupold w/mil dots so I can place my shots where I want. Thanx for your help----Sneaky

**Unclenick** · January 16, 2007, 06:36 PM

The 8x57 JS is a relativley variable pressure round, in my books. 35,000 PSI is the SAMMI maximum pressure listed and 49,300 PSI in the Vihtavuori manual. A fully modern rifle gets the 8x57 IS, which is the same exact cartridge, but loaded to 56,565 PSI CIP maximum pressure. Quite a difference. The lowest number is probably what needs to be observed in older guns, but a military design like yours in new condition should withstand the lower of the two CIP numbers. It may withstand the higher number, but I would consult a Mauser specialist on that point, have the chamber dimensions and headspace checked before trying it. You will want to be watching for pressure signs all the way as it is.

The N-560 will basically fill the case. Start at about 50 grains and work up toward 55. A lot of this won't burn in the barrel, so expect a lot of muzzle flash and blast. I wouldn't be surprised to see this slow powder have trouble lighting well and for the extreme spread of muzzle velocity variation to be high, but you can try it to see? Vihtvuori recommends something more like N140. The N560 won't exceed the lowest (SAMMI) pressure limit because it isn't really able to burn well in this cartridge geometry.

IMR 4895 is probably your best bet for the higher pressures CIP limit. Start with it at a very low 38 grains and work up to about 42 grains to stay inside the SAMMI limit, and then all the way up toward about 48.5 grains to reach the CIP limit. Watch for best accuracy between these limits and stop there.

BigJakeJ1s · January 16, 2007, 09:10 PM

Hodgdon has load info online for 8x57JS, using precisely that bullet with several of their powders, including Varget. They also have H4895, which is similar to (but not the same as) IMR4895 (generally, if one does well, there is a load for the other that will do well too). Their max load pressures top out around 49K CUP, whereas IMR's data is only to SAAMI specs, topping out around 37K CUP. SAAMI, IMHO, is biased towards US developed cartridges, over those developed elsewhere.

Andy

January 16, 2007, 05:17 PM	#1
sneaky pete Senior Member Join Date: November 24, 2004 Location: Florida Keys Posts: 510	8x57 JS Looking for load data I've got a m-48 Yugo in unissued condition and am looking for load data for 180 gr Nosler Ballistic tip .323 bullets. I have the following powder availiable. IMR 4895, Vagret, VihtaVouri N-560 and a little bit of RL-19. I'll primarilly be using this round for killing boars/hogs, but some deer also. The Yugo has a 2.5x8 leupold w/mil dots so I can place my shots where I want. Thanx for your help----Sneaky

January 16, 2007, 06:36 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	The 8x57 JS is a relativley variable pressure round, in my books. 35,000 PSI is the SAMMI maximum pressure listed and 49,300 PSI in the Vihtavuori manual. A fully modern rifle gets the 8x57 IS, which is the same exact cartridge, but loaded to 56,565 PSI CIP maximum pressure. Quite a difference. The lowest number is probably what needs to be observed in older guns, but a military design like yours in new condition should withstand the lower of the two CIP numbers. It may withstand the higher number, but I would consult a Mauser specialist on that point, have the chamber dimensions and headspace checked before trying it. You will want to be watching for pressure signs all the way as it is. The N-560 will basically fill the case. Start at about 50 grains and work up toward 55. A lot of this won't burn in the barrel, so expect a lot of muzzle flash and blast. I wouldn't be surprised to see this slow powder have trouble lighting well and for the extreme spread of muzzle velocity variation to be high, but you can try it to see? Vihtvuori recommends something more like N140. The N560 won't exceed the lowest (SAMMI) pressure limit because it isn't really able to burn well in this cartridge geometry. IMR 4895 is probably your best bet for the higher pressures CIP limit. Start with it at a very low 38 grains and work up to about 42 grains to stay inside the SAMMI limit, and then all the way up toward about 48.5 grains to reach the CIP limit. Watch for best accuracy between these limits and stop there. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

January 16, 2007, 09:10 PM	#3
BigJakeJ1s Senior Member Join Date: August 8, 2005 Location: Arlington TX Posts: 663	Hodgdon has load info online for 8x57JS, using precisely that bullet with several of their powders, including Varget. They also have H4895, which is similar to (but not the same as) IMR4895 (generally, if one does well, there is a load for the other that will do well too). Their max load pressures top out around 49K CUP, whereas IMR's data is only to SAAMI specs, topping out around 37K CUP. SAAMI, IMHO, is biased towards US developed cartridges, over those developed elsewhere. Andy