Tuesday, June 21, 2016

12 mm Remington brass from 50.70 Government cases

As another Lame Cherry exclusive in matter anti matter.

This is my technical data, based upon research I am conducting on the Swedish military round termed the Remington 12 mm.

In the examination of brass, it appears the Gaytube transformation of 50.70 Government rounds holds promise. The  process is in need of refinement, but the 50.70 cartridge does closely resemble the original.

Remington 12 mm Sweden

Bullet diameter .497 inches\12.615 mm
Neck diameter 12.17×42mm RF - 13.44 mm
12.17×44mm RF - 13.46 mm
Base diameter 12.17×42mm RF - 13.93 mm
12.17×44mm RF - 14.00 mm
Rim diameter 12.17×42mm RF - 15.94 mm
12.17×44mm RF - 16.00 mm
Rim thickness 12.17×42mm RF - 1.68 mm
12.17×44mm RF - 2.08 mm
Case length 12.17×42mm RF - 41.2 mm[1]
12.17×44mm RF - 44 mm[2]
Overall length 12.17×42mm RF - 51.78 mm
12.17×44mm RF - 57.38 mm
Primer type Rimfire
Filling Black Powder
Filling weight In Service; 3.89 or 4.09 Grams

50.70 Government American

Bullet diameter .515 in (13.1 mm)
Neck diameter .535 in (13.6 mm)
Base diameter .565 in (14.4 mm)
Rim diameter .660 in (16.8 mm)
Rim thickness .065 in (1.7 mm)
Case length 1.75 in (44 mm)
Overall length 2.25 in (57 mm)
Primer type Large rifle

50 Alaskan - Parent 348 Winchester - Parent Winchester 50 WCF

Case type Rimmed
Bullet diameter .510 in (13.0 mm)
Neck diameter .536 in (13.6 mm)
Base diameter .553 in (14.0 mm)
Rim diameter .610 in (15.5 mm)
Rim thickness .070 in (1.8 mm)
Case length 2.10 in (53 mm)

SomeSome have suggested the 450 and 500 Nitro Express as brass bases for the Remington 12 mm, but  the 50 70 Government surpasses the English loadings in being closer to the Swedish standards in all categories. Therefore the Nitro Express are rejected, as much as the 348 fire forming (trimming brass to length, then light charge forming in the breach). It is more feasible to remove brass from the rim of the 50.70 Government and then to light load in fire forming, resize in dies, and then produce safe full power loads.

50.70 length 44 mm
12 mm length 44 mm

12 mm bullet 12.65
50 50 bullet  13.1

50.70 Rim 16.8
12 mm Rim 16.0

12 mm neck 13.46
50.70 neck  13.6

It is therefore logically deemed that with rotary filing of the 50.70 rim to 12 mm sizing, this cartridge will load properly with the minimal effort.

With proper bullet sizing for the 12 mm bore, this is an affordable and available substitute. Logically, a drill press might be as readily used to trim the case rim of the 50. 70 to 12 mm dimensions, in a like type of jig.

Once again it is more simple to purchase brass, but when not available and when it is, expensive, an alternative must be sought, and with care and attention to someone with skills, it is possible to create such brass.

The adventure continues.

..... and yes my children, some of the children really enjoy this type of exercise of the mind.