FG 42, but designed around a non-German cartridge from day 1

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tomo pauk

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Apr 3, 2008
The historical FG 42 was designed around the rather stringent requirements, that stipulated use of the full-power cartridge in a hand-held weapon that is not heavier than 5 kg, the weapon being capable for the automatic and single-bullet fire.
It is my understanding that FG 42 ended up as a very good weapon (with almost cult-like following today), with the shortcomigns being that was expensive to make, and that the muzzle blast was sizable, to say at least.
So let's make it different this time - designers are allowed to use an existing non-German rifle cartridge, provided that the cartridge and an the initial number of barrels are easily available for Nazi Germany of the late 1941/early 1942. Cartridge does not need to be as powerful as the 7.92x57. The alternative FG 42 is not expected to be made in millions anyway like it is the case when the major change of regular infantry weapon change (here is about the thousands of weapons needed), so the logistics are not that demanding as it will be in that case.
The non-German cartridge used can be as-is, or with a bit of nip and tuck to fit better the new weapon; in the later case, it is required that original cartridge can still be used need-be. Weapon is still required to be able to do the automatic fire, while weight is to be up to 5 kg. At least 20 cartridges in a removable magazine, as per historically.

What cartridges might be the best choice, that can still make weapon useful at longer ranges while not 'beating' the weapon internals and the soldier using it? Lower powered cartridge should be making the smaller muzzle blast, and the automatic fire will be more controllable, but it might be worse off against the targets past, say, 500 m?

Impact on the development of the self-loading and/or automatic weapons after 1943?
 
6.5 Carcano
6.5 Arisaka
6.5 Mannlicher
with pointy bullets 120-130 grains (7.8-8.4 grams).

A problem with the FG 42 spec was that it was supposed to somewhat replace the MG 34/42 and needed longer range than the intermediate cartridge that was used in the MP-43.
The suggested bullets will mimic the trajectory of the 7.9mm well enough well past 500 meters. A 120 grain bullet will give 20% less recoil than the 7.9mm at the same velocities.
Adjust as desired to cut down muzzle blast vs long range trajectory. You can use a somewhat shorter and/or skinner case to get the velocity compared to the 7.9 X 57 case.

Using a shorter/lighter 7.5-7.9mm bullet hurts long range performance.
 
6.5 Carcano
6.5 Arisaka
6.5 Mannlicher
with pointy bullets 120-130 grains (7.8-8.4 grams).

A problem with the FG 42 spec was that it was supposed to somewhat replace the MG 34/42 and needed longer range than the intermediate cartridge that was used in the MP-43.
The suggested bullets will mimic the trajectory of the 7.9mm well enough well past 500 meters. A 120 grain bullet will give 20% less recoil than the 7.9mm at the same velocities.
Adjust as desired to cut down muzzle blast vs long range trajectory. You can use a somewhat shorter and/or skinner case to get the velocity compared to the 7.9 X 57 case.

Using a shorter/lighter 7.5-7.9mm bullet hurts long range performance.

6.5 Swedish

IIRC a number of studies have been made over the years, coming to the conclusion that the best (as in, compromise between weight, recoil, ballistics, and hitting power) military rifle caliber (and accompanying squad MG) would be a full power cartridge in the 6-7mm range with a long boat-tailed bullet.

Post-WWII both the Western and Soviet blocs chose expediency leading to the 7.62x51 and 7.62x39, respectively. And then the pendulum swung in the other direction, leading to the adoption of the 5.56/5.45mm systems.
 
6.5 Carcano
6.5 Arisaka
6.5 Mannlicher
with pointy bullets 120-130 grains (7.8-8.4 grams).

6.5 Swedish

Indeed, the different 6.5 mm cartridges make a lot of sense here, especially when looking back from today's era.
The 6.5 Swedish was also a Norwegian cartridge, and the 6.5mm was both Austrian and Dutch cartridge, so either will be easily available in Germany of late 1941. All of the European 6.5mm types will indeed need the spitzer bullet to work well.
BTW - Wkipedia does not note that there was a spitzer bullet for the Norwegian 6.5mm, but the German data plates do (9g bullet, velocity V25 of 745 m/s ) - ie. a bit weaker than the Swedish spitzer, but here this can be an advantage.

I wouldn't worry too much about a few mm of difference, after all the FG 42 worked with the long German cartridge.

I was trying to find the merit for the more powerful cartidges for this task, such are the 7.5mm French or the 7.65 Belgian (both being very modern for the day), but choosing these offers just minor saving in the forces for the weapon to withstand, so Germans might as well and go with the historical bullet.

Another cartridge that was pretty 'mild' when compared with the 7.92x57 was the Italian 7.63x51. With just under 2400 J, it is under the Arisaka's ~2670, let alone the big ~4000J of the 7.92. Italians were under pressure to miliatrize fast, and the 7.35mm stuff just didn't had enough of wherewithal to replace the 6.5mm, so they might be grateful for a shipment of, perhaps, French infantry weapons & ammo to the units in N.Africa in exchange for shipping the 7.35mm ammo & barrels to Germany. When compared with some 6.5mm cartridges, it is already with the spitzer bullet.
Yes, the 6.5mm cartridges with spitzer bullets will outperform it as the distances increse.

FWIW, here is Gun Jesus, and hi's opinion about the 7.35x51 might surprise you :)
 
I am a big fan of 6.5mm cartirdges and I have had two rifles built in 1990s for custom (at the time) 6.5mm cartridges.
1st was a 6.5mm X .308, an old wildcat from the 50s. Remington later introduced it as the .260 Remington.


And this may be larger than needed.

2nd was a 6.5rem benchrest. Basically the 6.5mm X .308 shortened from 51mm case length to 39.6mm length.

566px-6.5_lineup.jpg

2nd is the 6.5 Swedish,
3rd is the 6.5 Carcano
4th is the .260 Remington.
6th is the 6.5 Grendel.

My 6.5 BR was pretty much a bit fatter Grendel, It easily fired a 120 grain bullet at 2600fps using a type of powder available in 1938-40. The sharper shoulder may have given feeding problems in an automatic weapon? I had a limited budget and needed to use a cartridge case that would fit an existing bolt face.
If you can accept the lower weight bullet and the lower impact the 6.5 will give the the same long range trajectory as the 7.5-8mm bullets and the same wind drift.

5th cartridge in the picture is the 6.5 Creedmoor which was pretty much developed because the .260 Remington with long boat tail bullets has the bullets sticking down into the powder space (down past the shoulder) and doesn't really have much more capacity than the slightly shorter Creedmoor.
But in WW II nobody was using extra pointy bullets with long boat tails. Short or medium boat tails yes but those require more steps or care in manufacturing of the accuracy goes to pot.

6.5 Swedish is/was a great cartridge but it was designed in the 1890s for the powder available at the time and for some reason it is just a little bit bigger at the back end than the German 7.9mm Mauser and the US .30-06 (and family) and so with the lack of cheap brass in the use it was not good choice for me. The difference in 500 or so pieces of brass about equaled the cost of custom chambering.
 
My choice, as always, the Savage 250-3000, and it existed since 1915, based on the .30-06 case
1729207416779.png

It's a 2400 Joule class cartridge with 6 to 8 gram bullets at 8-900m/s
 
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