Loading the
12.7x44R Swedish
For the Rolling Block Rifle
Model 1867/74 manufactured in 1874 by Carl Gustafs stads Gevärsfaktori.
This article deals with the case forming required to form .348 Winchester cases into 12.7x44R Swedish.
Commercial cases are available from Buffalo Arms in Idaho if you should choose that as an alternative.
They're fairly expensive but not everyone has the perseverance to do the required work, and given my
knowledge of this procedure there have been times I questioned my choises! Since I'm now on the down
side of this learning curve I've come to appreciate these fine rifles and carbines as being significant
collectables and just plain fun to shoot. I hope that your endeavor is as satisfying as mine has been.
The first issue I'd like to address is the fallacy that this cartridge is the same as the U.S. .50-70 Gov't cartridge.
They're close, but not identical and the Swedish rifles will not chamber the .50-70 because the head diameter
of the .50-70 is larger than the 12.7x44R. I've seen a few of these rifles ruined by being re-chambered to
.50-70 after some knowledgable gunsmith or dealer told the owner it was the best thing to do ($$$$$).
The choise of the .348 Winchester case is obvious once you study the dimensions and feasibility. This is the
same empty case that shooters in Sweden utilize to form their own cartridges.
1- One of my handloads. Case has been fire-formed.
2- Swedish handload from .348 Win. case
3- German RWS factory case; handload from Sweden
4- Original Norwegian rimfire 12,17x42R
5- Original .50-70 Gov't
Left -Unfired handload. Notice the case is wasp-waisted.
Center -.348 Winchester case
Right -.50 Alaskan case mfg by Starline Brass
Update July, 2008: The .50 Alaskan shows great promise,.....
Actually, the .50 Alaskan case when trimmed to the correct length
will chamber perfectly fine in some rifles. But not all rifles.
The problem is the case wall thickness at the case mouth after
the case is trimmed. Its simply too thick for some rifle chambers
to chamber easily. Some shooters have reported polishing out the
chamber until the .50 Alaskan case chambers easily when trimmed
to the correct length. At your own risk...
You'll need a tubing cutter to cut off the .348 case neck at the bottom of the neck.
Next you'll have to figure overall length for the final trim. Using the 44mm length you'll end up with 1.730".
You'll notice in the above illustration that case length isn't exact in the various cartridges. I've found at
least one Remington rifle that required a shorter case length than 1.730", so allow for some fine tuning as you
go if your cartridges won't chamber easily. Use the 42mm length of 1.653" as the shortest length and perhaps
you'll find happiness somewhere inbetween.
Don't ask me why the original rimfire case is 42mm long and the civilian centerfire case is 44mm long.
I don't know!
If there's anything good about loading this cartridge its that you can use .50-70 dies.
These dies cost me $27 new.
These dies will deprime, neck size, seat and [may not] crimp bullets.
The bullet seater die body needs to be lathe trimmed to compensate
for the shorter case of the 12,7x44R.
Included with this die set is the Lyman M die. This die can be used to attach the many
expander plugs you'll need to open the case mouths to .512-.515".
The bronze item on the left is a powder compression plug. All these expanders attach
to the Lyman M die stem. The exact dimensions aren't important, just that you use as
many as 5 or 6 expanders to open the case mouth. In addition to these lathe-turned expanders,
I also used standard expanders from various die sets at the loading bench including the .429"
from the .44 S&W Special. Improvise!!
It is imperative that you ~anneal~ the case neck after you cutoff the neck and before you start
the expanding operations. The reason for this is apparent below.....
You'll have to experiement with the depth of the case expanding. Many of my earlier attempts were
too far down into the case and caused a buldge that wouldn't allow chambering. To remedy this
you may run the loaded cartridge into the sizing die to iron out that narrow buldge. Remember to
use case lube when you do this. Once the cases are fire formed you'll have no further problems and
the cases may be reloaded using the .50-70 dies just like they were made for it.
What bullets to use?
The first bullets I used were these Hornady Great Plains bullets. They're soft lead with a hollow base intended for muzzle loaders.
The body diameter is .500" while the driving band is .509".
The bullets I'm using now are these cast slugs. Left is 350gr .512" diameter, right is 450gr.
They are no longer available commercially.
I am going to start casting my own
.515" bullet shortly for this cartridge.
Powder
My first loadings used FFg and Pyrodex RS. Charge weights ranged from 62grs to 72grs, which just about
fills the case. The original Swedish military loading was 75grs with a 345gr bullet. The 450gr bullet above
with 72grs blackpowder is an impressive load! I fired all my test loads in a 1867 Husqvarna sporter weighing
7 lbs, so it was much lighter than the military musket. Over the blackpowder you'll need to use a wad card.
I bought 1,000 from Buffalo Arms but they're just as easy to make from waxed cardboard milk cartons, half-inch diameter.
It is absolutely imperative that there be NO AIRSPACE between the bullet and the powder!!!
Smokeless powder in an antique rifle?
You'll have to make this decision on your own. I have loaded Accurate Arms XMP5744 and Unique using data for .50-70.
Neither load produced anything near the recoil of the blackpowder load nor showed any signs of dangerous pressure.
I tend to load prudently and don't need full power smokeless loads for punching paper or plinking.
