Thanks 45 2.1 for the 8mmKAR

[Pb4me]

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My son shot the first cast out of the 8mm, a 1944 (dot) rifle with a like new bore. Load was once fired Federal brass, Remington 2.5 primer per the suggestion in the cookbook loads section from the CBA, 16 grains of 2400 and the 8mmKAR bullet checked and lubed with homemade lube. Alloy was mostly WW's. I say mostly because we shoot whenever we can into a large bullet trap filled with cut up pieces of tires. We recover our bullets about once a year so these bullets were once .45-70, .444, .35Rem, .44 mag, you get the idea.

Bullet was seated deep enough to just enclose the top lube band. I know this is deep and the bottom lube grooves are exposed to the fire, but obviously it worked well. We have only shot these at 50 yards so far and we will chronograph them and extend the distance in the very near future. These three shots were in 5/8's of an inch. Aiming point was at 6 on the bullseye and the rear sight set at 250 meters. Different seating depths may be tried in the future also but if this depth works with other loads we may leave it.

SR4759 was tried, (14 grains), again per the suggestion in the cookbook loads section from CBA and this load consistently put two shots into one hole and another about 1 inch away every time. We even tried positioning the powder and it continued this grouping. The strange thing is, the two shots touching or in the same hole were in the same spot every time and the loner was also in the same spot. We will probably stay with 2400 under this bullet and slowly increase the charge very little. Thanks for the info on this forum.
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[Aloxite]

Funny you should mention it. I cast a bunch of the Karabiners tonight out of a single cavity mold I bought here. I'm new to casting for rifles. I mixed up a Lyman #2'ish mix: 10 lbs of WW, 1 lb monotype, and 1 lb 37/63 solder. I probably err'd on the side of too hard. I don't think it could be a bad choice other than maybe a waste of alloying metal.

I'd like to find a load using either Varget or BLC(2) since I've got kegs of each. I'm loading for a well worn VZ-24 and a newish Yugo M-48.

[leadman]

2400 works well for me with a little more powder. SR4759 works excellent for me with a load heavier than what you are using. You could probably go up to 18grs or so and maintain good accuracy, this might get rid of the flyers also.
Don't know where you are located but here in Az 2400 will heat up a gun barrel much sooner than 4759. When it is 115' one has to take this into consideration.
I also have fired loads with the base and sides exposed to the burning powder but with these reduced loads it does not seem to matter.
Glad you and your son are having a good time.

[6.5 mike]

What weight is your mould dropping ? Been wanting to do some work with my cz-23 & pp'ed.

[45 2.1]

Your Welcome. You might also try Unique at or near the top of its burning range for the boolit weight your useing. There are a couple other really good 8mm boolits we've done. One of those is the 8mm Sil that is in the group buy discussion section.

[UBER7MM]

Pb4me,

I'm working on several test loads for the same cartridge/boolit. (see my thread: Load needed for 8 x 57mm / Lee 8MM Karabiner boolit)

I've found that OAL: 2.780" is as long as it gets for a clean throated chamber; crimped last lube ring and the boolit touching the rifling. I believe that if you want a longer cartridge you'll need to size the nose closer to the bore diameter of your barrel; an extra step in the boolit sizing process. The popular bore riding and paper patching diameter for an 8 x 57 JS .323" grooved rifle is .318" (data from reading archived threads). .318" is not a common drill/reamer size nor is it a standard size for retail sizers dies.

The two hole group and flyer may be cured by either increasing or decreasing your powder load by a half a grain to a grain or so. Sounds like you're almost there. Continue experimenting with SR-4759. Only experimentation will tell.


Good luck,