Machine Gun Barages

[Pete1000]

Hi, at what angles of elevation would a heavy machine gun such as a Vickers or an MG08 be used to fire a barrage? Secondly could a heavy machine gun in a concrete pill-box as used by the Germans in 1917 or 1918 actually fire a barrage or would they be restricted to direct fire?

[JMB1943]

According to Textbook of Small Arms, War Office Manual, 1929, p.277

”It is an observed fact that the greatest range of any hand gun occurs at an elevation of about 33 degrees, and not at the conventional 45 degrees. A revolver, a shot gun, a 0.22 inch rim fire and a service rifle all give their greatest range at about 33 degrees,....”

A Vickers machine gun, being nothing more than an automatic rifle firing 0.303, would also be expected to obey this observation.

 

Regards,

JMB

Edited 23 August , 2018 by JMB1943

[Pete1000]

Thanks JMB1943. So that brings me back to the second part of my question. Can a machine gun in a WW1 pill-box be elevated to anything like 33 degrees? Personally I can't imagine how it can but do any of you have any information on the physical restrictions of HMG's in bunkers?

[Stoppage Drill]

The problem wouldn’t really arise. A bunker is a defensive work, and rifle/mg fire would be directed at close, visible targets. 

A concentrated machine gun barrage would be indirectly aimed at targets as much as two miles away, and the guns could safely fire from pits.

[MikB]

10 hours ago, Pete1000 said:

Thanks JMB1943. So that brings me back to the second part of my question. Can a machine gun in a WW1 pill-box be elevated to anything like 33 degrees? Personally I can't imagine how it can but do any of you have any information on the physical restrictions of HMG's in bunkers?

 

It depends on the height of the slit and the thickness of the wall. If you have a slit, say, 6" high in a wall 18" thick, then the angle from the bottom inner edge of the slit to the top outer is arctan(18/6) = 18.43 degrees - allowing a bit less to allow for diameter of bullet and normal errors of setting. Don't know what standard WW1 pillbox slit dimensions were - if any standards existed - and don't think I've ever seen an actual WW1 pillbox.

 

Stoppage's comments above are also very pertinent - a machine gun barrage is generally an offensive or counteroffensive measure, and pillboxes are a local defence strongpoint.

(Afternote: I see from a google search that there are some WW1 pillboxes - mostly in UK as far as I noted. It still looks practically impossible to use them in the barrage role, unless there were to be a suitable concentration of enemy in an exceptionally favourable location for it.)

Edited 24 August , 2018 by MikB

[Pete1000]

Hi MikB and Stoppage Drill, thanks for confirming what I was thinking. Sometimes you have to ask a question like this just to make sure that you are thinking things through properly.

Regards

Pete

[JMB1943]

Pete,

 

Consider a pill-box with Dimensions,

wall thickness = x

height of slit = y

To put down the barrage at max range, requires that tan alpha = y/x

where alpha is elevation (33 deg) for max range.

So, y = x (tan 33) = x times 0.65.

Approximating 0.65 ~ 0.66, then 3y = 2x.

If you can find the typical values of wall thickness (x) of a pill-box, you can calculate slit depth (y) required to accommodate 

the required 33 deg elevation.

A wall thickness of 18” requires a slit height of 12”!!

 

Regards,

JMB

[Bombadier]

Surely the above calculation is only true if the barrel pivot is exactly at the edge of the slit. 

With the pivot away from the edge, the value of x would become thickness of wall + distance of pivot from wall. 

This would have the effect of increasing the slit width required to achieve the required elevation. 

Just my idle ramblings. For all I know, maybe the pivot was at the wall edge. 

Nigel 

[303man]

A little bit of detail here:  http://www.pillbox-study-group.org.uk/defence-articles/equipped-for-action/

 

[303man]

When using Mk VII ammunition the Vickers was only sighted to 2900 yds the Vickers range table for 1916 gives 3000 yds as 12 degrees 22.5 minutes of elevation.  The 33 degrees is theoretical maximun of a bullet in free flight which was about 4040 yds.  The beaten Zone of the machine gun is long and wide at high elevations and several guns may have been needed for these to overlap and put down enough bullets to deny the ground to the enemy.  At long ranges the beaten zone was good for enfilading fire but not that accurate used to harass and stop working parties deny movement along trenches etc. typical night barrage could be 750 - 4000 rds a night giving rates of fire 125 - 650 ish per hour not exactly raining bullets but enough to spoil your plans.

Edited 28 August , 2018 by 303man

[SiegeGunner]

One way to improve the angle of elevation of a machine gun mounted in a pillbox/bunker ... in particular for harassing indirect barrage fire at night ... was to take it out and mount it temporarily on the roof.  I have translated various German accounts over the years where this was done.  

[Heid the Ba]

To echo SiegeGunner I have read various British accounts which mention German machineguns mounted on top of bunkers. 

[MikB]

Some of this hinges on the definition of barrage.

 

Could you regard the crossing diagonals at a few hundred metres at knee height used against Allied offensive waves as a barrage? They weren't aimed at individuals, just timed so that troops would have to walk through them. They certainly denied ground.

[MikeMeech]

9 hours ago, MikB said:

Some of this hinges on the definition of barrage.

 

Could you regard the crossing diagonals at a few hundred metres at knee height used against Allied offensive waves as a barrage? They weren't aimed at individuals, just timed so that troops would have to walk through them. They certainly denied ground.

Hi

 

Surely a Machine Gun barrage is on the same principles as an artillery barrage so indirect fire, that is how it appears to me from WW1 documents.  Direct fire is not a 'barrage'.   A question may me is when does 'overhead fire' from MGs (a pre-war developed tactic) become a barrage?  How many guns?

The Fourth Army Tactical Notes of May 1916, para. 54 mentions overhead fire searching the enemy's communication trenches.  The XIII Corps orders for the 1st JUly 1916, mention MGs using overhead fire.

By December 1916 SS135, 'Instructions for the Training of Divisions for Offensive Action' Section XVI, n using indirect fire:

 

"The arrangements for the barrage fire for the whole Corps front may be co-ordinated by the Corps Machine Gun Officer, under the orders of the Corps Commander, but control of the barrage on each Divisional front must be entirely in the hands of the Divisional Commander immediately the attack starts."

 

So quite a few guns using overhead fire not direct.

 

Mike

[303man]

Extracted from the web:

The army wrote new tactics for the massed use of machine guns and published them in the official manual The Employment of Machine Guns.  in 1916, the British Army’s new machine-gun concept underwent a trial by fire.

One of the new tactics was “barrage fire,” whereby groups of gunners fired indirectly — that is, without necessarily seeing their targets — in order to prevent enemy troop movements, to give covering fire or to generally harass and suppress the enemy.  The gunners angled their weapons high so the rounds would arc over the battlefield, much like artillery does.

[JMB1943]

15 hours ago, Bombadier said:

Surely the above calculation is only true if the barrel pivot is exactly at the edge of the slit. 

NOT TRUE

With the pivot away from the edge, the value of x would become thickness of wall + distance of pivot from wall. 

NOT TRUE

This would have the effect of increasing the slit width required to achieve the required elevation. 

NOT TRUE

Just my idle ramblings. For all I know, maybe the pivot was at the wall edge. 

Nigel 

Try drawing the line of sight from the MG muzzle to bottom edge of slit to to top edge of slit.

Depending on the height of muzzle above ground level (h) and height of slit (bottom edge) above ground level (H), an MG set at 33 deg elevation can be fired from the back of the pillbox and the bullets will ricochet around inside.

As the gun is wheeled forward, a point will be reached at which the line of sight just grazes the lower and upper edges of the slit.

The location of the muzzle will then depend on h and H.

 

Regards,

JMB

[SiegeGunner]

One sector where the Germans used indirect/overhead machine-gun fire to good effect was the Belgian coastal strip, where the rear area behind the front lines, below the Yser canal, was largely sand dunes.  The ground was too open for safe movement on the surface during the day, so activity was concentrated into the hours of darkness.  The Germans therefore designated suitably sited machine guns to 'play' indirect fire across the rear zone at irregular intervals during the night.  Fatal casualties were few, but there were numerous woundings, some of key personnel (including the second-in-command of the RN Siege Guns, who received a serious head wound from a nearly-spent MG bullet while walking up to reconnoitre the state of the canal bridges), and night-time activities were disrupted and morale adversely affected.  It's arguable whether this harassing fire could be characterised as 'barrage fire', in the sense of massed guns, but it was certainly 'barrage' in the sense that it fell unpredictably from the sky and had much the same effect, at lower cost, as a searching and sweeping artillery barrage. 

[Stoppage Drill]

As you would never want to fire at 33 degrees anyway, this is all just futile trigger-nometry.

[MikeMeech]

Hi

 

Looking through the documents I have available, a US document published in August 1918 (No. 1320 G-5, 'Supplement to Machine Gun Drill Regulations (provisional 1917) and Provisional Machine Gun Firing Manual 1917') which would have followed 'Allied' practice at the time has Section 39 that states:

 

"Barrage fire by machine guns is the fire of a large number of guns acting under centralized control, directed on to definite lines or areas, in which the frontage engaged by a gun approximates 40 meters."

 

It joins the Artillery and Trench Mortars in carrying out Barrage Fire.

 

Section 42 mentions that:

 

"Guns for barrage fire are organized into groups and platoons.  The group normally consists of between 12 and 24 guns.  If the group is considerably larger, it will be necessary to divide it into sub-groups, each under a sub-group commander.  The group is commanded by the Group Commander, who is a Battalion Commander."

 

Section 44 deals with rates of fire, for example the rate of fire for long period barrage fire would be a 'slow rate' of 60-75 rounds per minute, this could be increased to a 'medium rate' of 125-150 rpm for a short period (max about half an hour).  A 'Rapid Rate' of 250-300 rpm would be used in response to SOS Calls, but only for a few minutes.  'Harassing Fire' would be at a rate of 1000 rounds per hour.  The rate of 'Belt Filling' was considered a major reason for using a 'slow rate' of fire in long period barrages, even with pre-battle 'stock piling'.

 

I hope that is of interest.

 

Mike

[MikeMeech]

On ‎28‎/‎08‎/‎2018 at 09:19, MikB said:

Some of this hinges on the definition of barrage.

 

Could you regard the crossing diagonals at a few hundred metres at knee height used against Allied offensive waves as a barrage? They weren't aimed at individuals, just timed so that troops would have to walk through them. They certainly denied ground.

Hi

 

In some British documents that would be classed as providing a "Screen of Machine Gun Fire" I believe.

 

Mike

[Matlock1418]

Was already writing a very similar topic question on "What is a Machine Gun Barrage"? - so glad I spared my embarrassment by stopping and checking the Forum first!

As I generally first thought, but much learnt ... and still wondering.

• if a MG was being used as part of an indirect MGB would it fire on a fixed line/elevation or perhaps variants of (and trust to only the beaten zone)? or would it traverse an arc and/or elevation (to increase the beaten zone/area)? or possible both - "it depends ..." ?  As per a fixed manual? or perhaps variable orders?

Acknowledging the value of general indirect harassing and/or denial fire MGB, but ... for more specific purposes ...

• In indirect fire would multiple gun MGB [or possibly even single MG use] be restricted to area(s) or [acknowledging there will always be a beaten zone, typically quite linear at distant range (rather more than at close range direct fire anyway)] would more linear fire be used in the way curtains/screens/belts, creating a box I believe, might be used/created by artillery? [e.g. offensively to prevent reinforcements reaching a position under attack by assaulting infantry etc., or defensively as a curtain/screen(s) etc.]

I'm thinking MGB ... Pill-box defensive role and direct fire [not being a MGB] I think now being largely recognised as a different topic(s)

 

And, anyone got a MG manual/weblink [or more] they can please share?? ... I'm sure many would find of interest - if anything, it might stop dumb questions like mine! ;-/

 

[I'm sure there must also be an opportunity for artillery gunners to compare/contrast with their barrages too - 'curtain', 'area' and 'box' I'm guessing, but ... I'm not a gunner, of any sort!]

 

Knowing there will be an answer, or few :-)  ... in hope ...

Thanks.

Matlock1418