# Why did the BAR have only 20 round magazines? **URL:** \ **Category:** Factual Questions\ **Created:** [May 28, 2011, 5:07am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531 "2011-05-28T05:07:18Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![No\_Wikipedia\_Cites](https://avatars.discourse-cdn.com/v4/letter/n/94ad74/32.png) [@No\_Wikipedia\_Cites](https://boards.straightdope.com/u/No_Wikipedia_Cites)\ **Post date:** [May 28, 2011, 5:07am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/1 "2011-05-28T05:07:18Z")
Ok I don’t get it: Why did the Browning Automatic Rifle have catridge/magazines that only help 20 rounds? Why not 30? Or more? 20 rounds in an auto goes quick. Even on single fire it seems a bit scroogy to have just 20 pops. ---
**Author:** ![Throatwarbler\_Mangrove](https://avatars.discourse-cdn.com/v4/letter/t/8c91f0/32.png) [@Throatwarbler\_Mangrove](https://boards.straightdope.com/u/Throatwarbler_Mangrove)\ **Post date:** [May 28, 2011, 5:12am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/2 "2011-05-28T05:12:01Z")
Because a 30 round mag would be too big and stick down too far, making the weapon difficult to fire when prone. Earlier models of the M16 had 20 round magazines for the same reason, although since the 5.56mm is a smaller round the issue was more manageable and they eventually went to 30. Few 7.62mm magazine fed rifles were issued with a 30 round mag. The Bren gun and similar weapons tried to get around this by mounting the mag on top. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 28, 2011, 5:15am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/3 "2011-05-28T05:15:45Z")
The later FAL, M-14, and G-3, as examples, also have 20-rd. magazines. Early Thompson submachine-guns has 20-rd. magazines. (This was increased to 30 rounds in 1941.) Twenty rounds was more than double the capacity of the M1 Garand, and four times the capacity of the Gew. 98 or Springfield. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [May 28, 2011, 9:05pm UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/4 "2011-05-28T21:05:31Z")
As it’s name indicates, the BAR was originally conceived of as an automatic rifle, that could be fired on the advance while storming trenches. Giving it a humongous magazine would have made it too heavy and unwieldy. In fact it ended up being used more as a man-portable light machine gun than an assault rifle. Compare it to the [Lewis Gun](http://en.wikipedia.org/wiki/Lewis_Gun), which in American versions fired the same 30.06 cartridge, but which was intended as a light machine gun from the beginning. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [May 28, 2011, 9:33pm UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/5 "2011-05-28T21:33:47Z")
> [@sassyfras](#): > > Even on single fire it seems a bit scroogy to have just 20 pops. Back then most rifles were fed with 5 or 10 round stripper clips. 20 rounds was already a net improvement over those. The British BREN gun (which served the same purpose as the BAR for the British army) only had a 30 round mag. The Chatellerault MG had 25. Only the German MG 34s and 42s and the Russian Degtyarev ran with substantially higher ammo loads that that in squad assault weapon roles (MG 37/42s could also go belt-fed or use 100 round drum mags in HMG roles, but in those contexts the US Army didn’t use BARs) ---
**Author:** ![Throatwarbler\_Mangrove](https://avatars.discourse-cdn.com/v4/letter/t/8c91f0/32.png) [@Throatwarbler\_Mangrove](https://boards.straightdope.com/u/Throatwarbler_Mangrove)\ **Post date:** [May 28, 2011, 10:08pm UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/6 "2011-05-28T22:08:06Z")
> [@Johnny\_L.A](#): > > The later FAL, M-14, and G-3, as examples, also have 20-rd. magazines. Early Thompson submachine-guns has 20-rd. magazines. (This was increased to 30 rounds in 1941.) Twenty rounds was more than double the capacity of the M1 Garand, and four times the capacity of the Gew. 98 or Springfield. The Canadian army issued an FAL with a 30 round mag and a bipod as a section machine gun. > **[L1A1 Self-Loading Rifle | Canada](https://en.wikipedia.org/wiki/L1A1_Self-Loading_Rifle#Canada)** > > The Canadian Armed Forces, the Ontario Provincial Police and Royal Canadian Mounted Police operated several versions, the most common being the C1A1, similar to the British L1A1 (which became more or less a Commonwealth standard), the main differences being a rotating disc rear sight graduated from 200–600 yd (180–550 m) and a two-piece firing pin. Users could fold the trigger guard into the pistol grip, which allowed them to wear mitts when firing the weapon. The Canadian rifle also had a sh It ... As you can see from the picture, they are unwieldy when firing from the prone, which is the place where you want to do most of the firing, and made the gunner are huge target on the horizon. The huge mags were also a PITA to carry - a AK-47 style chest rig was issued to gunners that would endlessly wack them in the face when on the move. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [May 29, 2011, 2:27am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/7 "2011-05-29T02:27:32Z")
> [@Lumpy](#): > > . . . the [Lewis Gun](http://en.wikipedia.org/wiki/Lewis_Gun), which in American versions fired the same 30.06 cartridge, but which was intended as a light machine gun from the beginning. A hijack if I may . . . Wouldn’t the “cooling shroud” of the Lewis gun actually tend to keep heat _in_? I mean, to look at it at least, wouldn’t it prevent the heated air in the barrel from dissipating quickly (into the surrounding air)? Or, phrased conversely, wouldn’t it prevent relatively cooler ambient air from reaching the hot barrel? Given that the shroud was actually used, my intuition must be faulty. I just am trying to figure out where I’ve made my mistake. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [May 29, 2011, 2:37am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/8 "2011-05-29T02:37:55Z")
From the linked Wiki article. > [@](#): > > The gun was designed with an aluminium barrel-casing which used the muzzle blast to draw air into the gun and cool down the internal mechanism. ---
**Author:** ![Hairy\_Bob](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Hairy\_Bob](https://boards.straightdope.com/u/Hairy_Bob)\ **Post date:** [May 29, 2011, 9:56am UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/9 "2011-05-29T09:56:16Z")
> [@runner pat](#): > > From the linked Wiki article. Also from wiki. [QUOTE=] There is some discussion over whether the cooling tube was effective or even necessary—in the Second World War many old aircraft guns which did not have the tubing, were issued to anti-aircraft units of the British Home Guard and to British airfields. Other weapons were used on vehicle mounts in the Western Desert and did not suffer without the tube. They were found to function properly without it, leading to the suggestion that Lewis had insisted on the cooling arrangement largely to show that his design was different from Maclean’s earlier prototypes.[12] Only the Royal Navy retained the tube on their deck-mounted AA-configuration Lewis Guns. [/QUOTE] ---
**Author:** ![Paul\_in\_Qatar](https://avatars.discourse-cdn.com/v4/letter/p/ccd318/32.png) [@Paul\_in\_Qatar](https://boards.straightdope.com/u/Paul_in_Qatar)\ **Post date:** [May 29, 2011, 1:15pm UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/10 "2011-05-29T13:15:13Z")
> [@KarlGauss](#): > > Wouldn’t the “cooling shroud” of the Lewis gun actually tend to keep heat _in_? I mean, to look at it at least, wouldn’t it prevent the heated air in the barrel from dissipating quickly (into the surrounding air)? I will bow to the more serious gun nuts on the board, but as I understand it… The cooling shroud actually worked. The muzzle blast would force air in (out?) of the shroud, cooling the barrel. In other words, cooling air flowed through the shroud while the gun was firing. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [May 29, 2011, 2:02pm UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/11 "2011-05-29T14:02:34Z")
Thanks for your answers (I am embarrassed for not seeing it addressed in the Wiki link). ---
**Author:** ![Mk\_VII](https://avatars.discourse-cdn.com/v4/letter/m/5f9b8f/32.png) [@Mk\_VII](https://boards.straightdope.com/u/Mk_VII)\ **Post date:** [May 29, 2011, 2:55pm UTC](https://boards.straightdope.com/t/why-did-the-bar-have-only-20-round-magazines/583531/12 "2011-05-29T14:55:30Z")
Also it protects the highly vulnerable gas cylinder, which even a small dent in will stop the gun.