Machine Guns

[ragamuffin]

Halo

Sorry if this has been posted before, but I'm trying to find out how far a round travelled from a Maxim, Vickers and a Lewis Gun. How far distance was the Arc of fire?

I have heard of figures up to 3 miles.

Also could anyone tell me the maximum distance a round travelled from an Enfield rifle and a Mauser?

Danke.

[Guest KevinEndon]

Have a look at this info,

http://www.diggerhistory.info/pages-weapon...-ww1-allied.htm

May answer some of your questions

[MikB]

Halo

Sorry if this has been posted before, but I'm trying to find out how far a round travelled from a Maxim, Vickers and a Lewis Gun. How far distance was the Arc of fire?

I have heard of figures up to 3 miles.

Also could anyone tell me the maximum distance a round travelled from an Enfield rifle and a Mauser?

Danke.

Just calling a gun a Maxim only describes its action design. Both the Vickers and Germany's MG08 were Maxims.

The cartridge is what determines the distance travelled, other things like angle of discharge, wind etc being equal. The max carry of the British .303 round was sometimes quoted as 7000 yards - somewhat more than 3 miles - but this would probably only apply in particular conditions, the usual being less or much less. 7.92x57 might've been a little further, but the effective ranges of the 2 rounds weren't really noticeably different. There would also be not much difference between a MG and a rifle using the same round.

I believe there are records of Vickers guns being used at 2000 yards and over on enemy troop concentrations on reverse slopes, where the dangerous space would be long due to the slope roughly matching the descending trajectory of the bullets. The MG08 could've done much the same.

But that would really only work for solidly-mounted, well-supplied and -observed guns able to keep up a sustained rapid fire. The Lewis didn't really have those capabilities, so in general would be effective only with direct fire up to perhaps 600 -800 yards. Carrying range would be similar, but dispersal at longer ranges would be so scattered as to be ineffective.

Regards,

MikB

[ragamuffin]

Gentlemen

I thank you very much for your kind replies.

There goes another theory out of the window

Danke

[jacobtowne]

Here are some additional exterior ballistics figures.

Extreme ranges from Hatcher's Notebook:

The first two are the .30-'06 Springfield cartridge.

fps = feet per second

MV = muzzle velocity

Cal. .30 M1 (174 grain Swiss boattail) MV 2600 fps - 5500 yards (3.12 miles). Optimum angle of departure was 34 degrees elevation.

Cal. .30 M2 Ball 152 grain MV 2800 fps - 3500 yards (1.99 miles)

For comparison:

.45 ACP 230 grain in pistol MV 820 fps - 1640 yards (.93 miles)

From Barnes's Cartidges of the World:

.303 Brit. Mk VII Ball 174 grain MV 2440 fps. No figues on extreme range.

JT

[TonyE]

Vickers rear sights in WWI were graduated to 2,900 yards and long range barrage fire was frequently carried out at these ranges in the latter part of the war.

In 1938 the .303 inch Ball Mark VIIIz was introduced with a boat tailed bullet and sights were regraduated on one side for Mark VII ammunition to 2,900 yds, and on the reverse for Mark VIIIz to 3,700 yards.

The Text Book of Small Arms 1929 reports that due to the effects of air resistance, the extreme range of a 174 grain .30 calibre "Swiss" bullet (i.e. with boat tail) is about 4457 yards at a maximum elevation of 34 degrees 42 minutes. This bullet had a ballistic coefficient of .406 and a muzzle velocity of 2600 fps.

Since the .303 Mark VII bullet had an M.V. of 2450 and was flat based not boat tailed, it could reasonably be expected that the extreme range would be about 4000 yards. Incidently, this elevation for maximum range of about 35 degrees applies to all small arms ammunition.

Regards

TonyE

[ragamuffin]

Halo

Well, many thanks guys for your valued information. I appreciate every reply and I knew you wouldn't let me down.

Danke

[ian turner]

I understood that the machinegun's range would be less than a rifle, because a proportion of the propellant gasses were used in operating the ejector spring mechanism of a machinegun.

Ian

[MikB]

I understood that the machinegun's range would be less than a rifle, because a proportion of the propellant gasses were used in operating the ejector spring mechanism of a machinegun.

Ian

Not really. Some MGs used a muzzle gas trap to accelerate the barrel assembly backward, but most of the energy used in cycling the gun was energy that the bolt rifle would just vent to atmosphere as gas pressure or thump against the firer's shoulder as recoil. By the time the gases got into the muzzle trap they were well past 'all-burnt', the pressure was dropping and the bullet was accelerating inconsiderably if at all. The approximate situation was that the mech made use of energy the boltaction would've just wasted.

Those with a gas port and piston bled off their pressure somewhat earlier, but still with very little ballistic effect.

Remember, the cycle of a machinegun is easily cranked through by hand, so probably consumes only about 10 ft.lb. energy, from a round typically developing about 2,500.

Regards,

MikB

[ian turner]

MikB

Thanks - I can see what you mean on one hand, but I still have a little doubt:

I guess I am thinking of more modern LMG's where the gas outlet is still behind the choke point, where the bullet is surely receiving the maximum pressure before leaving the barrel?

I thought the gas continued expanding until outside the barrel. I realise that at some point the effective gas-pressure cannot further increase, but if some of it is diverted to operate an ejector mechanism then I was under the impression (= from dad who was a Bren gunner) that the range of the bullet became less than from a rifle.

Maybe that was different for the maxim-type operation.

Ian

[MikB]

Thanks - I can see what you mean on one hand, but I still have a little doubt:

I guess I am thinking of more modern LMG's where the gas outlet is still behind the choke point, where the bullet is surely receiving the maximum pressure before leaving the barrel?

(= from dad who was a Bren gunner) that the range of the bullet became less than from a rifle.

Guns like the Bren were what I meant in the 2nd para. Yes, the gas is being tapped off before 'all-burnt', but the actual reduction in pressure behind the bullet from maybe 50cc of extra volume for it to fill is very small. Again, think of cocking a Bren manually - it uses at most a similar amount of work to cocking a 6-10 ft.lb. junior air rifle; maybe you should double that for the energy wasted in slamming against buffers in full-auto action, but it's still going to be much less than 1% of what's available. Since most barrels - rifle and machinegun - are not long enough to fully exploit the gas pressure for maximum velocity before venting - the effect of tapping-off is pretty much swamped by other variables.

Regards,

MikB

[ian turner]

MikB

Thanks once again. I have concluded that I would not choose to stand in the path of the bullet

at either one, two, three or four miles distance, to put the theory to further test!

Cheers

Ian

[Tim]

In regards to the SMLE, below is taken from 'Textbook of Small Arms - 1929'. The Mark VII ball round has a 174 grain bullet.

With a muzzle velocity of 2,440 feet per second, the length of time for it to 'arrive' is...

100 yards .2 second c. 2,200 fps. velocity

600 yards 1.0 second

1,000 yards 2.1 seconds

1,300 yards 3.1 seconds 880 fps. velocity (maximum range on No. 4 sight)

1,750 yards 5.1 seconds

2,000 yards 6.4 seconds 600 fps. velocity (maximum range on SMLE leaf sight)

2,600 yards 10.8 seconds (maximum range on volley dial sight)

2,800 yards 12.8 seconds 340 fps. velocity (maximum range on volley dial sight)

3,000 yards 15.1 seconds 300 fps. velocity

Cheers,

Tim

[Staffsyeoman]

To stretch this debate a little; a colleague of mine remembers an account where the writer refers to the 'crackling of the bullets overhead' from an MGC Company putting down a barrage. He is a former REME officer, so calculates that this is probably (in his words) 'a series of mini sonic booms', as the bullet leaving the muzzle of a Vickers is going at Mach 2 and would therefore be inaudible until it slowed..

Two questions - a) plausible theory? anyone recognise the source of the quote?

[TonyE]

Not just a plausible theory, but fact.

Anyone who has ever marked targets in the butts will be familiar with the "crack" as the round passes overhead. Markers use it to tell them their target has been fired at because you cannot identify the sound of the rifle shot as "yours".

I have marked in the butts for Bren competitions and the rounds do crackle overhead, but I cannot help with the source of the original quotation.

The bullet has to be going at a speed of below about 1100 fps (depending on atmospheric conditions)before it becomes sub-sonic and therefore does not make the "crack". This is why rounds for silenced weapons usually use heavy bullets to reduce the muzzle velocity to below the speed of sound.

The L34 silenced Stirling used normal Mark 2z ball, but it had a series of gas holes down the rifling to reduce the velocity and allow a more "gentle" escape of propellant gases. They worked even more effectively with the special 150 and 180 grain special sub-sinic loads.

Regards

TonyE