why 30 rounds?

[ccsniper]

I was wondering, why did most militaries settle on 30 round magazines? As far as I know it is the most common mag capacity. I know that the M14 and the M16 both originally had 20 round magazine, but not sure why they upgraded to the 30 rounder.

 

[Texan Scott]

Because 20-rnd mags don't make much sense in 3-rnd-burst weapons.

 

[EBShooting]

The military going to the 30 round mags for the M-16 durring Vietnam was in response to the AK using 30 round mags.

But I guess that is has to do with the most rounds for the weight.

 

[rcmodel]

Because that was the largest/longest magazine that would feed tapered case rifle cartridges 100% reliably.
Without being a full half-circle that wouldn't fit in a magazine pouch..
And still be short enough to use while shooting prone or behind cover.

Also, most full-auto assault rifles need a cooling period every so often before melting.
A forced mag change every 30 rounds gives a slight cooling period between long bursts.

rc

 

[X-Rap]

Stripper clips made for 10 rd increments along with what others have said.
There are some 40 rd available but prone sucks with a 30.

 

[Hardtarget]

Also, the 30 rounders seem almost the reasonable length limit when fireing prone. Maybe just moving around with longer mags could be awkward. The 30's even stick out a bit.

I don't own or shoot these. I'm just thinking about how it might work.

Mark

 

[armysniper]

First of all this should be a no brainer. 30 vs 20? War is about numbers. Basic tactics state that the more you have, the better chance you have at winning. Im sure back when the decision was made to switch it up, someone was thinking about winning.

 

[rcmodel]

the 30 rounders seem almost the reasonable length limit when fireing prone.

Thats exactly how it works.

And actually, a 20 round mag is plenty long enough when you got your face planted in the mud, trying to see your rifle sights, and keep from getting your head shot off, all at the same time.

I guess ones desires & needs change drastically when playing video games or blasting targets at the shooting range though.

rc

 

[Carl N. Brown]

At typical assault rifle or submachine gun full-auto rates (600 to 720 rounds per minute) a twenty-round magazine allows two seconds or less full auto fire before a magazine change is needed. The thirty round magazine allows 50% more firing time until magazine change is necessary. Over thirty rounds. and magazines begin to get cumbersome.

This issue actually goes back to the days of the Auto-Ordnance Thompson Submachine Gun in military use. In the early days of WWII, the M1928 was the only SMG available in any numbers to the Allies. It was used with the type "L" 50 round drum or the type "XX" twenty round box (Auto-Ordnance called them "stick" magazines.)

Wikipedia (source cited is Frank Innamico, American Thunder: The Military Thompson Submachine Guns, Moose Lake Publishing, 2000.)

Magazine developments

Military users of the M1928A1 had complaints about the "L" fifty round drum magazine; the British Army officially criticised "their excessive weight, the rattling sound they made...." and shipped thousands back to the U.S. in exchange for box magazines. The Thompson had to be cocked, bolt retracted ready to fire, to attach the drum. It attached and detached by sliding sideways which made magazine changes slow and also created difficulty in clearing a cartridge malfunction ("jam"). Reloading an empty drum with cartridges was an involved process.

In contrast, the "XX" twenty round box magazine was light and compact, it tended not to rattle, and could be inserted with the bolt safely closed. It was quickly attached and detached, and was removed downward making clearing jams easier. The box tripped the bolt open lock when empty, facilitating magazine changes. An empty box was easily reloaded with loose rounds. However, users complained it was limited in capacity. In the field, users frequently taped two "XX" magazines together to speed magazine changes.

Two alternatives to the "L" drum and "XX" box magazines were tested December 6, 1941 at Fort Knox: an extended thirty round box magazine and a forty round magazine made by welding two twenty round magazines face to face. Testers considered both superior to either the "XX" box or "L" drum. The thirty round box was approved as standard in December 1941 to replace the "XX" and "L" magazines. (The concept of welding two box magazines face-to-face was carried over with the UD 42 submachine gun.)

 

[rcmodel]

Anyone who has been in the old-school military knows those GI's could only count on their fingers and toes!

5 = bolt-action Krag, Mauser, & Springfield
10 = SKS/British Enfield
15 = M1 Carbine
20 = M14/M16/AK47.

Beyond that, you needed to call in squad level support and have them take their boots & socks off!

The guy that designed the first 30-round mag only had one other GI to help him, and he wouldn't take his brown Army boots off cause his untreated athletes foot was already disgraceful.
Had he done so, we would all have 40-round magazines now.

FYI: One Bulgarian GI didn't have boots or socks, so they got 40-round mags.

BTW: The M1 Garand's 8-shot clip was an aberration and started out as a 20-round enblock clip.
But for the fact John Garand had went to a dinner party to show off his invention and one of the generals spilled red wine on the blue-prints, it would have been too.

Garand cut a badly stained section of the drawing out with his straight-razer that night, and slightly hung over, presented the taped together plans to the war department the next day for acceptance.

Since all the generals were hung over worse then John Garand was, they apporved the 8-round clip without arguing about it.

Thats my story, and I'm sticking too it!

rc

 

[medalguy]

The story I heard was that the Garand started out with a 10 round box magazine, but after John Garand smashed two fingers in the rifle, when one of the generals asked him how many rounds it held, all he could put up were 8 fingers. Two were bandaged up.

 

[rcmodel]

Well, that story makes a lot more sense then my story!!

I gota go to bed before this story gets clear out of hand!

Oh oh! Too late, it already did!

rc

 

[RBid]

Thats exactly how it works.

And actually, a 20 round mag is plenty long enough when you got your face planted in the mud, trying to see your rifle sights, and keep from getting your head shot off, all at the same time.

I guess ones desires & needs change drastically when playing video games or blasting targets at the shooting range though.

rc

rc,

The possibility exists that some folks may interpret part of this post as an insult towards people who punch paper, or play video games. Personally, I try not to leap to conclusions. I thought that I would point this out, in case you simply hadn't considered the possibility that this would be the case. Naturally, insulting people in this way tends to be received as, "blowing out someone's candle, to make yours shine brighter". This, of course, is not very 'High Road'.

In case it's relevant:

I occasionally play Call of Duty, and I spend a lot of time at the range. These statements are also true for a number of friends of mine, who are/have been in the military or law enforcement. I am happy to report that choice of hobbies has not impacted our priorities, or perceptions of reality.

Thank you for your time, sir.

 

[rcmodel]

The possibility exists that some folks may interpret part of this post as an insult towards people who punch paper, or play video games. in case you simply hadn't considered the possibility

Oh, I considered it.
But at my age, I simply don't care.

And I do blast targets at the range with 30-round mags from time to time.
But I always prefered 20-round mags when my face used to get planted in the dirt occasionally.

Thank you for pointing it out though.
My bad!

I will probably do it again.

rc

 

[RBid]

Oh, I considered it.
But at my age, I simply don't care.

And I do blast targets at the range with 30-round mags from time to time.
But I always prefered 20-round mags when my face used to get planted in the dirt occasionally.

Thank you for pointing it out though.
My bad!

I will probably do it again.

rc

You're quite welcome, sir.

Have a great evening!

 

[YankeeFlyr]

Rcmodel said it all.

And then some.

 

[Deus Machina]

Yup, RC said it again.
IMO, in the case of rounds with straighter walls like the 5.56, it's because it's the largest that's not completely cumbersome and that you can shoot prone with.

20-rounders keep the FA limited, but when you're limited to semi or 3-round bursts (or just enforce short, controlled bursts more stringently) it became a matter of giving the soldiers the largest magazines they can shoot in position. More rounds on hand means more time shooting, and less getting shot at.

 

[EddieNFL]

I have about 75 30 round mags and with the exception of an occasional high round count match, I stick to 20 rounders. I can't even get in a proper prone position with a 30.

 

[parsimonious_instead]

The story I heard was that the Garand started out with a 10 round box magazine, but after John Garand smashed two fingers in the rifle, when one of the generals asked him how many rounds it held, all he could put up were 8 fingers. Two were bandaged up.

LOL... nice one... but, if it were true, strangely comforting that the inventor of the weapon was also the first to sustain an injury as he tried to put rounds into the receiver!

 

[fatcat4620]

Ask the bean counters, they make these types of decisions.

 

[Skribs]

Because 20-rnd mags don't make much sense in 3-rnd-burst weapons.

Neither do 25-round mags. Enter the FAMAS.

And actually, a 20 round mag is plenty long enough when you got your face planted in the mud, trying to see your rifle sights, and keep from getting your head shot off, all at the same time.

I guess ones desires & needs change drastically when playing video games or blasting targets at the shooting range though.

I'm a gamer, and I didn't take this as an insult. I agree with RC - if I had an AR, I'd be deciding between 20- and 30-round mags for HD, just because the 20 fits the gun's profile better IMO (and really, why do I need 30 for HD?). The Saiga with the 8-rounder that I rented at the range was way too cumbersome. I also realize that when you're punching paper or playing video games, your profile with the gun doesn't matter as much, especially in video games - your magazine can just clip through the floor. (For those who aren't familiar with video games, "clipping" is when two objects go through each other, i.e. if your slung rifle keeps going through your shoulder during the run animation or if you're against an object and your gear appears to go through it).

First of all this should be a no brainer. 30 vs 20? War is about numbers. Basic tactics state that the more you have, the better chance you have at winning. Im sure back when the decision was made to switch it up, someone was thinking about winning.

In that case, why didn't we go to 31-round magazines to beat the AK's 30? Or 35 or 40 if you want nice multiples of 5 or 10?

 

[EddieNFL]

Oh, I considered it.
But at my age, I simply don't care.

That's because you were born before generation O(ffended) came along.

 

[RBid]

Making assumptions and broad based statements about groups of people, based on something like choice of hobby is a silly practice. I'm not personally offended by it, in the slightest. To me, it is akin to a junior high kid assuming that 'golfer' = 'fat, old, white guy'. As with any generalization, validating samples will likely exist, as will numerous examples of people who don't fit the stereotype.

/shrug

 

[mnrivrat]

Because gummit counters ran out of fingers and toes at that moment and had to stop !

 

[checkmyswag]

I've been considering keeping a 20 in the mag well for ease of toting around and keeping things compact while carrying my 30 round mags.