WWII AT rifle grenades

[Redbeard]

Working on an ATL I studied various WWII rifle grenades for AT use. In this search I found the training manual of the post WWII (Korean war) Energa AT rifle grenade and here it is emphasised, that the grenade is under no circumstances to be fired with any part of the rifle's butt plate in contact with any part of the body but with the butt under the armpit (if not rested on some "firm stop" or on the ground for indirect fire).

The Energa was a stop gap introduced during Korean war as the earlier WWII rifle grenades (like M9 on M7 launcher) were found ineffective vs. Soviet tanks of the 1950s and was a little heavier than the M9 (645 g vs 590 g) but were the M9 and similar WWII rifle grenades (like British mrk 68) also limited to no-shoulder firing?

I came across the post WWII (1956) French APAV mrk 2 which fired a 40 mm AT grenade using an ordinary bullet round (bullet trap type) to propel the grenade and judging from various You Tube clips this and later developments could be fired from a "normal" shouldered position, but with visible and impressive recoil (very much varying with the firer however, just as with heavy hunting rifles).

https://en.wikipedia.org/wiki/APAV40

Would it be plausible to have a rifle grenade in service by mid 1941 which could be fired from the shoulder and be effective out to appr. 50 m against early WWII tanks like R35, Pz I-IV, early "Cruisers", BT7 and T26?

BTW I wonder why no recoil dampers apparently were used in these rifle grenade launchers. In hunting rifles quite simples devices like recoil counterweights and muzzle brakes have been in use for decades but I suppose the post WWII hunter is seen as a delicate customer in opposition to how the GI was seen upon by the top brass .

 

[tomo pauk]

Recoil was very dependant on mass of projectile, mass of propellent gasses, and mass of 'launcher' (rifle in this case). Heavier proejctile, bigger mass of gasses, and lighter rifle = greater felt recoil, and vice versa.
With rifle firing bullets, the propellant gasses represent a good percentage to recoil force/momentum. When a heavy grenade is launched, propellant gasses represent just a fraction of total mass (projectile + gasses) leaving the barrel, thus employment of muzzle brake will barely help.
A rifle grenade that is fired from a rifle in 'normal' position would've probably meant the recoil comparable with the recoil of the Boys AT rifle, or the PIAT mortar. Aproach with heavy rifle and 'normal' firing altitude was used with the Granatbüchse 39 - the PzB 39 (weight 25 lbs) AT rifle with bipod converted to a grenade launcher.
FWIW, when I was in the Army, we were instructed to use rifle grenades strictly in 'under the armpit' position, with sling belt spaning around the elbows, the darned thing recoiled heavily.

 

[arctic warrior]

Isn't the whole idea of a military rifle to keep it simple; making it possible to survive rough treatment without crucial parts breaking. I remember kicking the MG62 loadinghandle if something got jammed to get it working again.
Would you trust your precious hunting rifle to somebody that has never held a firearm in his/her hands before? No I thought so! It would be why you had infantry and specialist grenadiers and riflemen. More complicated weapons meant more training something you don't give your ordinary conscript infantryman.

 

[marathag]

As always, Gun Jesus to the rescue, fulling in the details

Mentions you can fire from the Shoulder, depending.

 

[tomo pauk]

As always, Gun Jesus to the rescue, fulling in the details

Mentions you can fire from the Shoulder, depending.

Thank you. Looks like the blank cartridge will launch the rifle grenade from a rifle in shoulder position to about 50 yds. The more powerful 'rifle grenade cartridge' will push beyond 200 yds, with much greater recoil.

 

[Redbeard]

Isn't the whole idea of a military rifle to keep it simple; making it possible to survive rough treatment without crucial parts breaking. I remember kicking the MG62 loadinghandle if something got jammed to get it working again.
Would you trust your precious hunting rifle to somebody that has never held a firearm in his/her hands before? No I thought so! It would be why you had infantry and specialist grenadiers and riflemen. More complicated weapons meant more training something you don't give your ordinary conscript infantryman.

Well I haven't yet been up against game so big that I needed rifle grenades (my Grizzly dropped nicely to a 375 H&H and the Moose can be handled with a 6,5x55 mm), but actually I have an old k98 from 1941 for the "rough" hunting where my original Steyr-Mannlicher full-stock carbine was too delicate to go. But now I use another piece of German quality equipment - a Blaser R8 with two exchangeable pibes (a 308 Win and a 9,3x62mm) - that has never let me down - no matter how rough it got

Concering the rifle grenades I think most armies had a dedicated "grenadier" in each squad, but other squad members usually carried ammo.

For my 1941 ATL the rifle grenade is an obvious choice as rifle grenades were used already by WWI (French VB system) and it wouldn't be that complicate to change the old hand grenade with a shaped charge AT round.

I don't think it would be at all impossible to train conscripts to use rifle grenades - my experience actually is that the average conscript is a "faster learner" than the average enlisted man. After all I tought conscripts to compute artillery gun data with slide rulers and "handheld" trigonometrics - all in less than six months

 

[Redbeard]

As always, Gun Jesus to the rescue, fulling in the details

Mentions you can fire from the Shoulder, depending.

Excellent and thank you

A 50 yard max range shoulder fired probably was from a 45 degree firing angle, so in a firing angle where you would actually hit a tank size target I guess we are at about 30 yards range - or what the famed initial Panzerfaust could achieve - in 1943.

The Panzerfaust had a much larger warhead though and once you have some basic knowledge of rocket and/or recoilless technology I guess the idea to propel the AT charge with a rocket or recoilless charge from a tube is obvious.

 

[The Wizard]

U. S. Army training manuals on rifle grenade have from the mid 1940's included firing rifle grenade from the shoulder. The rifles covered by these manuals include the M1903, M1917, M1 Rifle, M1 Carbine and the M14. Grenades covered are the M9A1, M29 (Energa) and the M31.

 

[Cryhavoc101]

Well I haven't yet been up against game so big that I needed rifle grenades (my Grizzly dropped nicely to a 375 H&H and the Moose can be handled with a 6,5x55 mm), but actually I have an old k98 from 1941 for the "rough" hunting where my original Steyr-Mannlicher full-stock carbine was too delicate to go. But now I use another piece of German quality equipment - a Blaser R8 with two exchangeable pibes (a 308 Win and a 9,3x62mm) - that has never let me down - no matter how rough it got

Concering the rifle grenades I think most armies had a dedicated "grenadier" in each squad, but other squad members usually carried ammo.

For my 1941 ATL the rifle grenade is an obvious choice as rifle grenades were used already by WWI (French VB system) and it wouldn't be that complicate to change the old hand grenade with a shaped charge AT round.

I don't think it would be at all impossible to train conscripts to use rifle grenades - my experience actually is that the average conscript is a "faster learner" than the average enlisted man. After all I tought conscripts to compute artillery gun data with slide rulers and "handheld" trigonometrics - all in less than six months

Interesting - In his book Gen. Peter de la Billière talks about the difference in training Conscripts and volunteers (he was running an infantry training course over 2 years which included the last intake from National service and the first that was comprised of all volunteer) - he said that it took half the time to bring the all volunteer class up to the 'fully trained' level expected compared to the previous years conscript class allowing the volunteers to learn additional skills. Such as blowing shit up.

This matches my own experiance regarding differing classes where people all wanted to be there and those were some did not and pulled everyone down with them!

 

[Redbeard]

Interesting - In his book Gen. Peter de la Billière talks about the difference in training Conscripts and volunteers (he was running an infantry training course over 2 years which included the last intake from National service and the first that was comprised of all volunteer) - he said that it took half the time to bring the all volunteer class up to the 'fully trained' level expected compared to the previous years conscript class allowing the volunteers to learn additional skills. Such as blowing shit up.

This matches my own experiance regarding differing classes where people all wanted to be there and those were some did not and pulled everyone down with them!

My impression was that the conscripts included a lot of different people, incl. some very intelligent and already reasonably well educated (compared to their age) young men. The volunteers/enlisted men OTOH had a larger portion of those who really didn't have an alternative. But while the conscripts were faster to learn they were not necessarily as stable - often too much talking and too little work...

 

[marathag]

Thank you. Looks like the blank cartridge will launch the rifle grenade from a rifle in shoulder position to about 50 yds. The more powerful 'rifle grenade cartridge' will push beyond 200 yds, with much greater recoil.

With US grenades, the user could add the 'M7 Auxiliary Cartridge' the the grenade itself, that the troops called the Vitamin Pill.
It added about 30-50% to the range, and recoil, too.
https://books.google.com/books?id=wZ0eDAAAQBAJ&pg=PT131

 

[riggerrob]

The biggest problem is the small amount of explosive carried by a rifle grenade. Even with a shaped charge, it would only penetrate thin top skins of WW2 tanks. Plunging fire is easy to arrange, but difficult to range. How do you teach WW2 GIs to calculate range accurately enough to hit tops of tanks?

 

[marathag]

The biggest problem is the small amount of explosive carried by a rifle grenade. Even with a shaped charge, it would only penetrate thin top skins of WW2 tanks. Plunging fire is easy to arrange, but difficult to range. How do you teach WW2 GIs to calculate range accurately enough to hit tops of tanks?

For the period in the US, Baseball.
60' to the pitcher's mound, 90' to 1st base, 127' to 2nd Base from Home.

Distance gauging wasn't the problem.

no practice shooting at 20mph moving targets, that's the real problem

 

[bsmart]

The biggest problem is the small amount of explosive carried by a rifle grenade. Even with a shaped charge, it would only penetrate thin top skins of WW2 tanks. Plunging fire is easy to arrange, but difficult to range. How do you teach WW2 GIs to calculate range accurately enough to hit tops of tanks?

Ever wonder why the American WWII bazooka was the small size it was? It was designed to use the AT Rifle grenade projectile as the round with a rocket added at the rear. This was done to shorten development time since the shaped charge round for the rifle grenade had already been developed and tested. They only needed o perfect and test the rocket motor and launching tube.

 

[marathag]

Ever wonder why the American WWII bazooka was the small size it was? It was designed to use the AT Rifle grenade projectile as the round with a rocket added at the rear. This was done to shorten development time since the shaped charge round for the rifle grenade had already been developed and tested. They only needed o perfect and test the rocket motor and launching tube.

The lightweight warhead also allowed a smaller rocket motor, one that could complete its burn before leaving the tube, so the operator didn't get flashed with exhaust, like the later, larger ones did

 

[Redbeard]

Apparently the guy behind the Bazooka (Dr. Robert H. Goddard) had experimented with rockets launched from tubes already during WWI and the wiki link below even states that the development of the Bazooka was delayed to Goddard suffering from tuberculosis.

https://en.wikipedia.org/wiki/Bazooka

IOW it would appear possible to have a Bazooka like weapon if someone much ealier than 42/43 - if someone ask for it - and certainly if the designer can stay healthy?

Were rifle grenades used against tanks in the Spanish Civil war? I haven't heard about it and although systems like the WWI French VB ssytem probably was used I take they didn't have any AT ammo. But as tanks were used widespread (in the infantry support role) I take it wouldn't be impossible to have someone writing a report about how difficult it was to hit a tank with a rifle grenade and that the infantry needed a true man portable AT weapon at squad/platoon level to prevent "tank-terror" to prevail.

 

[NoMommsen]

...
BTW I wonder why no recoil dampers apparently were used in these rifle grenade launchers. In hunting rifles quite simples devices like recoil counterweights and muzzle brakes have been in use for decades but I suppose the post WWII hunter is seen as a delicate customer in opposition to how the GI was seen upon by the top brass .

Additional "recoil counterweights" would have needed ... more weight on the whole rifle ... or some additional and or heavier device to be fitted on the rifle before firing ... and be carried arond before using or even thinking to use it.

"Muzzle breaks" would rather decrease the range of the grenade.
Other than a bullet, that is accelerated by the propellant gasses already within the barrel, the grenade would be "propelled" only when the gasses this the rear part of the grenade ... at the end of the barrel ... behind any muzzlebreak-contruction fitted on the rifles barrel.
A muzzlebreak would substantially reduce the amount of prepelling gas hitting the grenade.

Recoil was very dependant on mass of projectile, mass of propellent gasses, and mass of 'launcher' (rifle in this case). Heavier proejctile, bigger mass of gasses, and lighter rifle = greater felt recoil, and vice versa.
...

Where does the "greater mass of propellant gasses" comes from ?

AFAIU the question was about a rifle grenade fired with the charge of a normal rifle cartridge ?
Same amount of propelling/gun powder produces the same amount of preopelling gasses.

 

[tomo pauk]

...

Where does the "greater mass of propellant gasses" comes from ?

AFAIU the question was about a rifle grenade fired with the charge of a normal rifle cartridge ?
Same amount of propelling/gun powder produces the same amount of preopelling gasses.

The mass of propelling gasses will be different coming from big cartridge (.30-06 or .303) vs. smaller cartridge (6.5 Carcano or Arisaka).

 

[marathag]

Additional "recoil counterweights" would have needed ... more weight on the whole rifle ... or some additional and or heavier device to be fitted on the rifle before firing ... and be carried arond before using or even thinking to use it.

US made some rubber slip on recoil pads

but were uncommon

 

[arctic warrior]

@Redbeard during my time with the Air Force we were told by instructors that we did have rifle grenades but wasn't to fire any. BTW in the good old days they told us they would fire the Energa from the shoulder and of course it would become blue and black and sore for days. But it was doable.
We also had a discussion on the Carl Gustav some time (years??) ago. It could have been built during early WWII years so the possibilities are there. Ah there it was https://www.alternatehistory.com/forum/threads/early-rpg.378551/#post-11838017