Heavy for caliber 8x57 cast load

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Potashminer

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I cast up about 5 pounds of wheel weights into a mold labeled "8mm KAR" - is/was made by Lee to a design that is oversize and heavy for caliber to be used in worn mil-surp 8x57 barrels. On line, I found references that these were nominally 225 grain, but, as many others on various chat rooms have found, mine have come out at 237-238 grains, .326".
I have been unable to find any published loads for 8x57 cast bullets in this weight range (say, 230 to 250 grains). A couple on LoadData, but they are for jacketed bullets (250 gr. Woodleighs). Lyman's 49th only lists a 165 gr. cast. Speer #14 is up to 200 gr., but again, jacketed. Hornady 7th, Nosler 7th are no help either, regarding cast information.
I have 5744, SR-4759 and H-4895 on hand for cast bullet loads. Can anyone point me to some reference to get me started with this 240-ish grain 8x57 cast load, please.
 
Thanks guys. This "heavy for caliber cast bullet" is sort of new terrain for me. Yomomma's link has only a single fellow mentioning H4895 with the Karibiner bullet - most of the rest of the guys there that are loading heavy cast (including Buckshot) seem to be using slow burning surplus powders - that got me to thinking that maybe heavy for caliber led one to slow powder, whereas most cast loads with "normal" weights that I am familiar with seem to be more toward the faster powders. Andy, thanks for sharing your experience - I do believe I am going to try out some of those.
One would have to believe that a 235 grain flat nose .325" or so bullet, at 1700 or 1800 fps, would pretty well do whatever needs doing with a mil-surp iron sighted rifle... ...
 
OP;
First load an un-primed, resized empty case with your boolit and crimp it snug in the crimping groove. Chamber it, eject it, then see how much the boolit is engraved by the rifling. If the boolit is engraved much beyond 1/16", then that's going to be an issue to deal with as far as ease of closing the bolt. The long boolit will most likely limit you to single loading your rounds due to the length of the magazine. (Most of us lead bombers single load anywho.)

As for powders and a good starter load, try 16.0 gr. of 4759 held in place with a pinch of kapok filler. For 5744, go 18.0 gr. These should put you in the 13-1400 fps. range to help avoid leading with softer alloy lead. Pushing wheel weight lead to much beyond 1400 can result in erratic accuracy in many rifles. No worries about pressures with these loads at all.

I get 1300 fps. in my 9.3x57 using 280 gr. Bullet Barn hard cast ahead of 19.0 gr. of 4759 and this load shoots quite well from my Husqvarna 46a.
:)
 
Thanks, Shell Shucker - I actually water dropped the W-W as I cast them - was going to let them age for a week or so, then will do the Lee Hardness test - with "normal" weights, I have actually had real good luck confirming suitability of published loads by following his guidelines for hardness versus chamber pressure (at least as far as I can use muzzle velocity as surrogate for chamber pressure). I agree with your implication that best accuracy with minimal leading is the objective here, and the actual velocity will be what it will be. I'll be using a Husqvarna 648 first , and then will try to make them work in a new M48 barrel on a Brazil 1908 action
 
Potashminer said:
Thanks guys. This "heavy for caliber cast bullet" is sort of new terrain for me. Yomomma's link has only a single fellow mentioning H4895 with the Karibiner bullet - most of the rest of the guys there that are loading heavy cast (including Buckshot) seem to be using slow burning surplus powders - that got me to thinking that maybe heavy for caliber led one to slow powder, whereas most cast loads with "normal" weights that I am familiar with seem to be more toward the faster powders. Andy, thanks for sharing your experience - I do believe I am going to try out some of those.
One would have to believe that a 235 grain flat nose .325" or so bullet, at 1700 or 1800 fps, would pretty well do whatever needs doing with a mil-surp iron sighted rifle... ...
Click to expand...

1700 or 1800 fps will be about the MV limit for a cast bullet of this weight (~235 grs) in the 8X57, as that's all the MV you can attain while keeping the pressure at or below about 30K psi (which is typically even a gas-checked cast bullet max pressure). When you want 30K psi or less with a cartridge the size of the 8X57, you pretty much eliminate the "Medium Speed" powders (~4064-4350) because they won't burn reliably at that pressure. That leaves the faster powders like I've suggested. As well, some shooters use full cases of slower powders, 4831 being a common choice. Oft times cast bullet shooters will use a slow powder because the shooter got a great deal on bulk slow surplus powder, and they obtained decent accuracy. I don't use them because it consumes 2-3 times as much powder as a fast powder, and I have never found a slow powder load that was more accurate than a slow pistol powder like SR4759, or a fast rifle powder like one of the 4198's.

8X57 Loading Tip: when loading the 8X57, you'll notice a dearth of cast bullet loads, and a degree of limitation on the bullet weights for which data is published. I have found that 30-06 loads for the same bullet weight transcribe nicely. Of the 30-06 loads that I've compared, they generally are very close, and a bit on the low side of what could be used in the 8X57. I do this for cast bullet loads, which are well below SAAMI pressures, so there is a large measure of safety if one of the 30-06 loads is slightly higher than a same-bullet-weight 8X57 load. For jacketed bullets, I use 30-06 loads as a guide and/or sanity check only, not willy-nilly straight up.
 
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One more thing to be aware of with the Kar is that when you seat them deep and allow the shank to protrude below the case neck, accuracy goes away. Like all cast bullets, they are designed to be seated with the bullet base at but not below the base of the case neck. In my rifle, the throat is not worn so I must seat them deeply into the case to chamber. The solution is a case filler. I use puf lon, and it makes all the difference in my rifle. If you find that you are also seating the bullet so that the shank is below the case neck, be aware of this. BTW, I use H4895 to get 1800 fps. The KAR is extremely accurate in my surplus Mauser 98. By that I mean 1.5 inch 5 shot groups at 100 yards. Regularly day after day. For a rifle made under war time duress in 1944 shooting a home cast bullet with Lyman peep sights that is very satisfying. Without the Puf lon it was scattering all over the place and I almost gave up!
 
If you have load data using H4895 for a jacketed bullet of the same weight, you could try the 60% rule that Hornady published. Take 60% of a max load for a reduced charge load. It usually gets the velocity down enough for cast bullets. Only safe to do with H4895 (though many old timers say they've done it with IMR4895 and it worked perfectly).
 
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