Practical (non-cyclic) MG rates of fire?

Discussions on the small arms used by the Axis forces.
Steve Wilcox
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Practical (non-cyclic) MG rates of fire?

Post by Steve Wilcox » 12 Mar 2008 20:27

I was wondering if there were any experten here who would help with some infomation about practical (not cyclic) rates of fire for certain machine guns?

The Handbook on German Military Forces (pages 314-315) says practical rates of fire were:
le.MG34: 100-120 rounds per minute
le.MG42: 250 rounds per minute
s.MG34: 300 rounds per minute
s.MG42: 500 rounds per minute

In Osprey's World War II Infantry Tactics, Company and Battalion by Dr Stephen Bull, it says regarding the s.MG34 that "The 1940 Handbook of the German Army suggests that a common rate of fire was about 300 to 350 rounds per minute." Page 20. This was apparently a 1940 publication by the British government.

On page 16 of that same Osprey work, regarding the M1917A1 it says:
"As the 1942 Heavy Weapons Company manual observed:
'The calibre .30 heavy machine gun is a crew served weapon capable of delivering a large volume of continuous fire. Medium rate of fire (125 rounds per minute) can be sustained indefinitely. Rapid fire (250 rounds per minute) can be fired for several minutes, but steaming will occur within two to three minutes."

And on page 17 it says in reference to the Bren LMG:
"According to Light Machine Gun (1939), the best that could be expected, with changes of barrels and magazines taken into account, was 120 rounds per minute in short bursts."

In an article entitled The Browning 1919A4 and 1919A6 Machine Guns in Vietnam by Frank Iannamico available at:
http://www.smallarmsreview.com/pdf/Browning1919.PDF there is has some infomation regarding the M1919A4:"The air-cooled heavy barrel could keep the A4 weapon at operating temperature for approximately 30 minutes at a rate of fire of about 60 rounds per minute. A rate of approximately 150 rounds per minute could be maintained for about 15 minutes, but faster rates of fire could only be maintained for short periods."

And the M1919A6: "Although it could fire indefinitely at the slow rate of fire of approximately 40 rounds per minute, it could maintain a medium rate of about 75 rounds per minute from 25 to 30 minutes. At a rapid rate of 150 rounds per minute it begins to overheat after about five minutes firing."

FM 23-45 Browning Machine Gun, Caliber .30, HB, M1919A4 (I've just got a PDF version of this) says: "The machine gun, caliber .30 M1919A4, is provided with a heavy barrel which is exposed to the air. This factor serves to keep the gun at operating temperatures under normal conditions, i.e., at the rate of fire of 60 rounds per minute for about 30 minutes."

US Army Infantry Divisions 1942-43 by John J. Sayen Jr. says the M1919A4's " Cyclic rate of fire was 400-550 rpm; practical rate was 60-120 rpm."

And the M1917A1's "Cyclic rate of fire was 400-600 rpm. Thanks to its water-cooling the gun had a practical rate of fire of 125 to 250 rpm."

Somewhere on the Internet I saved information from a now forgotten site about Soviet weapons that stated that the DP had a practical rate of fire of 80 rounds per minute, the Maxim 1910 could do 250-300 rpm practical and that the SG43 had a practical rate of between 300 and 350 rounds per minute. Edit: Found it: http://wio.ru/galgrnd/ww2mg.htm

Regarding the SG43, I've read that in Military Small Arms of the 20th Century (5th Edition)that "The barrel is air-cooled and massive in construction, thereby contributing to the fairly high overall weight. The bore is chromium-plated amd able to withstand continuous fire for long periods, although the barrel can be easily changed by releasing a simple barrel lock and the carrying handle allows a hot barrel to be lifted clear without difficulty." Page 275.

So does anyone have any thoughts on these numbers in general and/or anything solid on the SG43 in particular? :)

Edit: I didn't know if I should include the non-Axis MGs alongside the Axis MGs in this thread or whether I should have made separate posts in the Allied sections, but I figured (perhaps wrongly) it would be okay to include them here as I was trying to see how the German MGs stacked up against the others in terms of non-cyclic firepower. Apologies if this is too broad a post for this sub-forum. In particular I probably should have put the SG43 question at the end in a more appropriate sub-forum. :(

Tony Williams
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Re: Practical (non-cyclic) MG rates of fire?

Post by Tony Williams » 16 Mar 2008 08:00

For rifle-calibre guns (there was little difference between .303", .30", 7.62x54R and 7.92x57), the following factors apply:

1. Water-cooled barrels: can carry on firing almost indefinitely at close to the cyclic rate as long as the water and ammo don't run out (see: Vickers in WW1)

2. Quick-change air-cooled barrels: can carry on firing almost indefinitely as long as the supply of cool replacement barrels doesn't run out, but more slowly as time has to be allowed for barrel changes. However, in practical terms the number of spare barrels was usually small, so after working through them once, the RoF would have had to slow right down. If you had a stream running next to you, you could dump the hot barrels in that to cool them faster, as long as you didn't mind sending up lots of steam to advertise your position.

3. Fixed air-cooled heavy barrel: permitted a longer period of continuous fire initially than a light barrel, but once it got hot, it took longer to cool down.

4. Fixed air-cooled light barrel: number of rounds fired very limited before having to slow right down to avoid overheating.

For both 3 and 4 above, around 60 rpm continuous is probably more or less right. I do know that the .50 M2HB (heavy barrel, RoF c.450 rpm) has a continuous RoF of 40 rpm. The light-barrel .50 M2 aircraft gun would have a ruined barrel at the end of a 30-sec continuous burst.

Chrome-plating the bore could certainly help to improve the number of rounds fired before overheating became a problem, but not bby a huge amount. Nowadays they use stellite liners, which are I understand much better.

Tony Williams: Military gun and ammunition website and discussion forum

Steve Wilcox
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Re: Practical (non-cyclic) MG rates of fire?

Post by Steve Wilcox » 16 Mar 2008 15:39

Thanks very much for the reply, Tony! I was hoping you might see this thread and respond. I've enjoyed both your website and your very informative posts here at AHF. :)

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phylo_roadking
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Re: Practical (non-cyclic) MG rates of fire?

Post by phylo_roadking » 17 Mar 2008 04:17

Tony, just as a matter of interest - how vulnerable to damage by "corrosive" ammo is a hard-chromed bore??? I'm asking, because engineer's "hard chrome" on motorcycle suspension components can even be affected by the phosporic acid in dead bugs!

Tony Williams
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Re: Practical (non-cyclic) MG rates of fire?

Post by Tony Williams » 17 Mar 2008 07:55

I'm not sure. The people most likely to know are those who shoot military weapons for a hobby and buy surplus ammo from various sources.

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The Edge
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Re: Practical (non-cyclic) MG rates of fire?

Post by The Edge » 17 Mar 2008 10:43

Always problems when your equipment has bugs in it! :?

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