Swedish RB 12.7x44 to 50-70

[BlackpowderSweden]

I have recently reformed some hundred PPU 8x50R Lebel cases and they are the closest fit to the original of any reforms I have ever made!
After expansion in three steps they come out about 46mm long for a 2mm length trimming.

[MOA]

I sized the .515 boolits down to .510 in a push thru lee sizer die. I then after running the 50 Alaskan brass thru a 50-70 FL sizing die trimmed it to 42mm. I then just expanded the mouth of the case just enough to seat the boolit (450gr.) to proper depth and then tested for chambering. It chambered fine. I found on my brass the brass was the same thickness after trimming as it was at the mouth of the original brass before trimming. The 50 cal plains boolits are backed by a hard card and 55 grs of RS pyrodex, the 450gr boolits are backed by 12 or 13 grains of unique. Will check when I get home. At work now, having my lunch.

[MOA]

So, let me get this straight. I need 50/70 or .50 Alaskan brass, trim to length that will let me seat a Lyman .50 caliber Plains bullet, full length size my brass, powder and seat the bullet with thumb pressure over a card wad and good to go? I have one of these rifles on the way, and another one a buddy recently got to load for the 2 of them.No need to crimp the case on the bullet?

Koger, you need IMHO one or the other, or some 50-90 brass. It just depends on how many steps you want to have in the process from start to finish. The 50 anything from Winchester is going to mean you have to reduce the size of the base, the 348 Win means your going to go through lots of fire forming and losing brass to splits, I found for me the simplest was going the 50 Alaskan route, only because I did not want to mess with the base or the splits in the cases, and I could not find any 348 Win anywhere at the time, which may have been a blessing in disguise.

I also think that to a certain extent each gun is different, and there is just enough difference in all the chambers that it is only going to work when we each do custom fitting of the cartridges in the chambers. What works for me may not work in your rifle, but what we get by posting our results is we get a lot of ideas that we can try on our own rifle to see if it will work. I just got in a Lyman .512 lube sizer die that I'm going to try on the .515 boolits just to see what happens as opposed to not sizing and pan lubing which is what I am now doing to see if it effects fit and chambering. Will post if results are interesting.

The other thing that you have to keep in mind is how the Swede's engineered this chamber, barrel and cartridge to work, one the chamber is tight, why???? Because they were using a basic Winchester 50-70 case necked down to hold a .497 diameter boolit that had a hollow base that would expand when 60 plus grains of black powder behind it went off, so the 497 dia boolit being of soft lead would fill the larger .512-.515 groove dia bore, you have to remember that lots of fouling is going to be occuring when these military and paramilitary folks are shooting these rifles in any conflict, so small boolits, large bore = more shots before cleaning. If we just had a mold that would reproduce the lead boolit that was used in these guns from the beginning, most all else would be simple.

If when you are sizing the brass, and you are doing a full length resize that should cause you to have to open up the mouth slightly to get the boolit in, that should be enough tension so no crimping will be needed, I do not have to crimp any of my shells at all.

[Gray Fox]

The need for such a boolit should be communicated to the gentleman in Croatia who I bet could turn out a beautiful mold for this cartridge. GF

[Wolfer]

1 of my 12.7 needs a .515 boolit. 50 Alaskan brass trimmed to 44 mm and sized, loaded with slightly modified 50-70 dies chambers and shoots great with the lee 450 gr and 12.5 gr of unique.

My other one needs a .510 boolit. I made a dummy round with a 44 mm case and .510 boolit and slid it in until it stopped. Measured the distance that it needed to go and trimmed my brass accordingly. Turned out to be 42 mm.

So I have one 12.7x44 and one 12.7x42. Since they need different sized boolits it's pretty easy to tell them apart.

If shooting black powder boolits that fit the bore good can be hard to chamber after a few shots. That's why they used undersized bullets.

I'm quite certain these unique loads will handle deer fine.

[Col4570]

This is my 50-70 Rolling Block Rifle by Remington.it takes both 50-70 and 12.7x44 Rounds.

[MOA]

Col4570, Nice looking roller there. Are you sizing your boolits or shooting them as cast?

[BlackpowderSweden]

There is a stopring-bullet availabe here:

https://svartkrutt.net/shop/en/loadi...et-mould.html?



A larger diameter driving band naturally limits the seating depth.

Technical data:

Bullet weight: 430 grain (pure lead)
Base diameter: 12.8mm (.505")
Driving band diameter: 13.36mm (.526")
Length: 22.8mm (.899")
The mould block is made from aluminum. Handles are included

[MOA]

Great info BlackpowderSweden, I just got off the phone with Lee Precision, if you want this mold it will cost you $250 plus for one mold, and if you want two, another 250.00 Smackeroos. Can't say I'm impress with Lee Precision.

[koger]

Thanks MOA and Blackpowder swede for the info. I know what I need now to make either rifle work and shoot well, it is just now up to see what each rifle likes and adjust from there.

[Old Coot]

It shouldn't be hard to get a "replica" of that bullet mould from Accurate Molds. Just specify what you want the molds are lathe bored on a CNC machine. It is simply a matter of putting in the correct sizes along with a drawing of the bullet. Brodie