Win760 and the Karabiner in the 8x57

[UBER7MM]

Has anyone used Win760 with the Lee/MidSouth Karabiner boolit in the 8x57? I'm looking for a starting load. IMR-4350 and H4831 for the same boolit and cartridge would also be helpful.

Thanks for your help,

[melter68]

Used win760 43grs with the standard lee 8 x 57 174gr mold, quite good load but
not used any low loads.

There must be lots of people out there who shoot low loads, with the results they need.

[melter68]

Come on Guys, there must be someone who has tryed that combo

[MtGun44]

The closest I have used is not too close at all - 748 in a .45-70.

Hodgdon H414 is W760, and they show loads for 200 Jbullets starting at 45 gr for 2229 fps
and a max of 50 gr for 2475. US loading data for the 8x57 is notoriously low pressure,
out of fear for an old gun with the wrong barrel size.

Best I have.

Bill

[UBER7MM]

Thanks for responding Bill,

I think the next question is "How does the starting load data of a 200gr J-word correspond to a 200 gr cast boolit?"

Is there a formula?

[oldarkie]

sorry never used win760,but I have tried imr4350,and like it.i started at 30grs andworked up to 36grs.30grs to 33.5 was mild recoil very accurate with no pressure signs,34grs was still accurate but the primer backed out a little. 35grs was the same.at 36grs I lost accuracy and the primer started to flatten.hope this helps some.

[madsenshooter]

Velocity with the cast bullet would be higher, pressure lower. I've got no set formula, but the tables Richard Lee has for cast bullets in his book were based on extrapolations from jacketed bullet velocity and pressure data. Here's an example. I was using a 30/40 which is close in capacity to the .308, which Lee has data for. With 41gr 760 under a 190 cast bullet I was getting 2337fps. Lee shows 2190fps with 41300psi pressure. I know that my alloy won't take that much pressure, peters out at about 37000psi, so actual pressure was less than that. So roughly we can say velocity with an equal weight cast bullet will be a couple hundred fps higher, while pressure will be 4000psi or so lower. I say roughly, cause there's a lot of variables at play here, for example bearing surface of the cast bullet we're using, alloy hardness, etc.

[shredder]

While I have not used either of those powders I have used that boolit over top of IMR 4895, for 1850 fps. It is a real killer. I believe with 760 you will need to have a load that comes close to filling the case. That might not work out in reality very well. 4350 is likely a better choice.

[melter68]

Good info guys, every little helps,
cheers chris

[UBER7MM]

Great intel!

Looks like I'll have some experimentation to do.

Thank you gentlemen.

[oldarkie]

I tried imr4831 yesterday,started at 32grs worked up to39grs.had about the same results as 4350 but no accuracy from any load,3or 4inch groups,dont know why.

[felix]

Reason: the boolit was warped going from case to enclosed barrel. Tailor the powder with it's ignition to make the boolit have a quicker response as not to have "time" to distort. ... felix

[Good Cheer]

My 375296 hunting load uses a compressed charge of 760 with a CCI-250 in the .375x45-70. Wonderful stuff. Wooosh.
But I really don't remember ever trying 760 in the 8x57.

[UBER7MM]

Reason: the boolit was warped going from case to enclosed barrel. Tailor the powder with it's ignition to make the boolit have a quicker response as not to have "time" to distort. ... felix

Felix,
.
Are you suggesting a faster burning powder? Please advise. I appreciate any knowledge or experience you might have in this area.
.
Thank you in advance,

[melter68]

Just loaded up 32 grs of win 760 in 10 303 cases, going to range tomorrow, so will try. Used
150gr cast gas checked boolit head with CCI primer.
Keep you updated.
Then if that works will try in a 8mm case too.

Only loaded up the 303 cases because i have my full quota of 8mm ammo.

[UBER7MM]

Melter,

What was your verdict at the range the other day? Please advise.

[melter68]

Melter,

What was your verdict at the range the other day? Please advise.

Well, the boolits shot and got down range, so the powder at 32 grs is ok, but i used sized
boolit heads and i should have used unsized boolit heads, as the mold was for a 30/40 krag,
i was told.
So i will load some more unsized heads, but lubed.

Also i shot them at 300m, because i forgot i had the trial rounds, should have tryed them at
100m.
I am sure that these will be ok.

Hope this helps

[Kraschenbirn]

Been away for awhile or I'd have stuck my oar in here sooner. I shoot the Lee 329-208 (designed for the Steyr M95) sized down to .325 and loaded over 36.0 gr. WW760 with a dacron fill in both my Yugo M48 and my M38 Turk. Never chrono'd this load but I'd estimate somewhere in the 1800-1900 fps range with acceptable accuracy. (2 1/2"-3" 100M groups with issue sights). Have to admit though, that 760 isn't my preference for the 8x57 but, for now, I can buy 760 locally while I can't find H4895 (my first choice) anywhere.

Bill

[UBER7MM]

Been away for awhile or I'd have stuck my oar in here sooner. I shoot the Lee 329-208 (designed for the Steyr M95) sized down to .325 and loaded over 36.0 gr. WW760 with a dacron fill in both my Yugo M48 and my M38 Turk. Never chrono'd this load but I'd estimate somewhere in the 1800-1900 fps range with acceptable accuracy. (2 1/2"-3" 100M groups with issue sights). Have to admit though, that 760 isn't my preference for the 8x57 but, for now, I can buy 760 locally while I can't find H4895 (my first choice) anywhere.

Bill

Bill,
.
That sounds like you've found the "sweet spot" of W760, cast boolits and your rifles. Thanks for sharing.
.

[melter68]

Yes Bill,
Thanks for that, i take it your M48 is the .323 size bore etc.
Will investigate that load.
Many thanks.
chris