The military barrels in 8x57JS will vary the pressure,mostly down,and thus the velocity.Ken Waters in his Pet Loads wrote about that.

John, this could be a possibility in the velocity difference we had with Blue Dot. roger

Roger,

If , more like when, I get a chance to get down your way, I am going to haul all of my stuff with me and we are going to check out your stuff and my stuff, side by side, on your chronograph and mine.

That descrepency is driving me batty also.

Cheers and good shooting
seafire

I'm using 4350, loads about 48 grains.

I'm still working up though. I plan on using this for hogs eventually.

Found my load book...



The best load for my 22" barrel Steyr Professional 8x57 with the 200 grain Nosler Partition is 49.0 grs. H-380 with an F-210 primer.



Last time I took that load to the range (elevation +400' from sea-level, temp ca. 40 F, RH 55%), the 5-shot chrono average was 2,460 fps at 20', with a SD of 3.33 fps, forming a group of 0.702 MOA at 100 yards.



A.C.

Canuck, I have found the same thing with H-380 in the 8x57, very low sd numbers. I like 54gr's with a 175gr Sierra

Took out the 8X57 yesterday, here are some of the results;

200 gn speer

IMR 4064

45.5 gns 2376 fs primer OK

46 gns 2420 fs OK

46.5 gns 2436 fs no pressure still

W-760

50 gns 2354 fs

51 gns 2386 fs

52 gns 2473 fs no pressure signs

IMR 4350

50 gns 2347 fs no pressure

51 gns 2368 fs primer flattened

S&B fmj 196 gn loads

2478 fs

2460 fs

2458 fs

The only bullet I was able to obtain 2600+ fs with was a 180 gn BT. (48 gns 4064) 2668 fs.

Usual disclaimer here.....!

I concluded that Nosler is feeding us BS..

BTW, the gun is a M-48 Yugo with a long throat M-98 bbl installed.

Ray Atkinson and Seafire and others have raised an issue that applies to 6.5 x 55, 7 x 57, and 8 x 57 cartridge chambers in at least military barrelled rifles. If we seat bullets progressively deeper into the case with any given powder we are reducing the volume of the case. This of course increases the pressure of that load. Lee's manual gives minimum oal's for their loads. If you seat the bullet to a longer oal, you're increasing the case volume and lowering the pressure (at least compared to deep seating the bullet). As you increase the oal, either the magazine length or the location of the lands limit just how long you can go. At some point (very dependent upon the particular rifle ) you may just clear the lands with the chambered cartridge. Now with little or no "running start" before the bullet hits the lands, logic would seem to indicate that pressures would tend to rise; perhaps a little or perhaps a lost.

What are your thoughts on pressures rising as you lenghthen oals in these cartridges which have a lot of free bore in their barrels?

The first thing I did yesterday was to chronograph 2 pairs of loads. All four used 185 gn RCL's and identical everything, but the seating depth varried a great deal between the two pairs. One was seated to the cannelure, the other pair were seated out to the lands. There was no discernable difference in the velocities or accuracy at all. This is hardly conclusive, but there it is.



Id like to do some more testing with this when time permits. Especially with heavier bullets and slow powders.

As far as heavy bullets go, I have played around with Hornandy 220 and sierra 220 grain.

I found that IMR-4831 works well for heavy bullets in the 8mm. Both of those bullets over 52 grains of IMR-4831 went ave. of 2410 fps. These loads where shot out of my Yugo M-48. I have loaded up to 53 grains but was a little hot...well in my rifle

Jason