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Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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Squad Support Weapon   Army Guns 20+mm

Started 17-Jun by stancrist; 22278 views.
renatohm

From: renatohm

11-Jul

Same situation as the 40mm duo - big bro is too powerful for individual weapons.

Thinking again on this, maybe a Neopup derivative firing the bigger 25mm could be a good choice.

schnuersi

From: schnuersi

11-Jul

renatohm said:

Thinking again on this, maybe a Neopup derivative firing the bigger 25mm could be a good choice.

It could even use a 30 mm grenade.
The Neopup IMHO suffers from the fact that they wanted high MV for long range and penetration. The Neopup launches the 20x42 at higher speeds than a 40x53 is typically fired. The recoil impulse is massive. In the region of typical for rifle grenades. The recoil mechanism compensates for this so we can assume this level of impulse is acceptable for such a weapon.
The 110 g 20 mm grenade is launched at ~300 m/s. Which results in a recoil impulse in the area of 30 Ns. So a 300 g grenade launched at 100 m/s would be possible for such a weapon.
It comes down to what trajectory and what payload is required.

EmericD

From: EmericD

11-Jul

schnuersi said:

Its not. Everybody knows they are ineffective. This is why almost nobody uses them anymore.

Given the fact that most western armies stopped using RGs, only to replace them with the 40 x 46 mm HEDP which is even less effective, I don't think that "RGs lack of effectiveness" was a real criteria.

schnuersi

From: schnuersi

11-Jul

EmericD said:

I don't think that "RGs lack of effectiveness" was a real criteria.

Agreed.
But the other way round: if they were effective they might have not been replaced. Especially not by something even less effective in the AT role.
The idea of using grenade launchers as AT weapons was abandoned.

EmericD

From: EmericD

11-Jul

schnuersi said:

But the other way round: if they were effective they might have not been replaced. Especially not by something even less effective in the AT role.

Clearly, at the time RGs were dropped, they were considered ineffective against tanks.

But at this same time, the 40 x 46 mm HEDP was considered effective against all other light vehicles (or at least sufficient), and THAT is no longer the case...

nincomp

From: nincomp

11-Jul

EmericD said:

a rifle grenade with the same payload as a 40 mm LV grenade will still be heavier than a 40 mm LV grenade (because of the grenade tail)

Since a rifle grenade weighs more than a 40mm LV grenade, what is the breakeven where the number of rifle grenades equals the same number of 40mm LV grenades + underbarrel grenade launcher?  

I am easily confused.  Is the more pertinent argument that 40mm LV grenades have too little HE so the better option would be rifle grenades with their higher payloads?

Mr. T (MrT4)

From: Mr. T (MrT4)

12-Jul

Rifle grenades are much more limited in terms off effective range and dealing with armor and bunkers has been relegated to LAW like launchers instead of riflegrenades.

In reply toRe: msg 124
gatnerd

From: gatnerd

13-Jul

I think the issue with Rifle Grenades is one of accuracy. How accurate are they, and how many RG's will a rifleman ever fire to be able to get combat accurate with one?

In the initial (I'd argue, wiser) use of the 40x46, the US had a dedicated Grenadier, armed with a M79, and thats what he did. His job was accurate grenade delivery, and both his practice and combat employment was largely focused on building and improving that skill set.

Given the huge trajectory, low velocity, and shitty sights, these weapons require a serious amount of 'zen' feel for the weapon and range to be used accurately, which is possible with practice. 

I was talking to a Vietnam marine awhile back, and he describes their grenadier being in the zone, and just blowing a VC sniper out of a distant tree on his first shot. Meanwhile he tried firing the M79 later and couldnt hit the broadside of a barn because he didnt have that 'zen' feel for the trajectory. 

M79 Grenade Launcher

Loading and firing the M79 Grenade Launcher.The M79 grenade launcher was a single-shot, shoulder-fired, break-action grenade launcher. The U.S. Army M79 fir...

Without extensive practice via dedicated grenadier (or a sophisticated smart scope) I suspect most of these low velocity weapons, whether they be RG's or 40mms, will have similarly poor accuracy to this guy in Iraq, whose dropping rounds right into the street in front of him, missing an entire building sized target thats just across the street in the middle of the day. 

Combat Camera: Marines Enter Fallujah, Firing M-203 Grenade Launchers (2004)

Vootage of Marines firing M-203 grenade launchers from a building corner at a car across the street. Scenes include Marines entering the city and clearing ea...

schnuersi

From: schnuersi

13-Jul

gatnerd said:

I think the issue with Rifle Grenades is one of accuracy. How accurate are they, and how many RG's will a rifleman ever fire to be able to get combat accurate with one?

This also is an intresting question.
I think it not only depends on the ballistics (trajectory, accuracy) but also on payload. How close to you have to get to achieve effect.
During WW2 the German rifle grenade launcher was considered to be accurate and effective. From all acounts it has been a pretty popular weapon. The GL-attachment was concidered a general piece of equipment and every soldier was trained with it. Although it seems in practice usually a dedicated grenadier used it.
As a side not the sight was considered so useless that it was common practice to shoot the GL just by guessing and pointing. Which according to records was easily done with a "litte" practice.
The standard HE grenade had a diameter of 30 mm, weighted 0,288 kg, 30 g explosive payload and was launched ~65 m/s. Since the grenade is heavier compared to 40 mm LV but has a comparable explosive payload maybe the fragmentation was better giving a larger area of effect resulting in the accuracy being concidered acceptable or good?

gatnerd

From: gatnerd

13-Jul

schnuersi said:

As a side not the sight was considered so useless that it was common practice to shoot the GL just by guessing and pointing. Which according to records was easily done with a "litte" practice.

I've got a fair bit of experience with low velocity, high trajectory shooting. I used to build 'air cannons' for several years when I was a teenager, out of PVC pipe pressurized to 100psi. They could shoot a potato through a piece of 10mm plywood, and launch little PVC darts 500 yards. It helped that I lived directly next to a hardware store at the time.

Since the pressure was constant, and projectiles fairly uniform in weight, accuracy was surprisingly good - when in the 'zen' state of predicting high trajectory. I once hit a paint can on my first shot at 75yds standing - while holding over the can by several feet. I could just 'feel' that I was on target.

But when not in that zen state, accuracy could be wildly off base. Especially as distance increased.

I recall shooting at a bilboard sign down the street about 200yd that had an anti smoking PSA on it (was a fan of smoking as a teen.) A billboard is huge, but my elevation estimate was tremendously off. Ended up putting a potato through a guys open convertable roof who was driving by - I was 50 yards short and 50' low from my estimates. Needless to say that was the last attempt at that particular target.

Now a rifle grenade is going to be more accurate than a smooth bore potato launcher - but I suspect it would be a lot closer to a potato then a rifle bullet in terms of hit probability. 

I think any of these man portable HE launchers - whether they be 40x46, x51, rifle grenades, 60mm comando mortars, or RPG/Recoiless type launchers - really need some type of 'smart scope' to make maximum use of the limited number of rounds and small warheads. 

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