PDW/sub-gun question

[Fletchette]

I have noticed a lot of sub gun designs that have their magazine mounted 90 degrees to the action. Some even seem to sacrifice some ergonomics in order to do this. Why? semi-auto pistols feed quite well with a grip angle built into them.

The "Linda" and "Terry" pistol/carbine designs are proof of non-90 degree designs working, and they seem to point better. Why are so many others not built this way?

 

[Nightcrawler]

Well, many subgun designs date back to the WWII or post war era. Magazine designs were as simple as can be, and a vertical box mag is about as simple as it gets (feed reliability is the priority).

Nowadays that's not such an issue, but it's still basically tradition. Also, a magazine that sticks downward vertically won't interfere with any other manipulation of the weapon. One angled backward might interfere with one's firing grasp or something, if not executed properly.

 

[Zak Smith]

I see as the main reason, in a 90* magazine (e.g. MP5), the cartridges move only "up" the column as the top round is fed into the action. In an angled magazine, they must move both "up" and "forward."

 

[Fletchette]

I see as the main reason, in a 90* magazine (e.g. MP5), the cartridges move only "up" the column as the top round is fed into the action. In an angled magazine, they must move both "up" and "forward."

Why is this a problem? Just about every semi auto pistol magazine operates in this way.

 

[DMK]

Why is this a problem? Just about every semi auto pistol magazine operates in this way.

Perhaps "semi auto" are the operative words. Not many full autos have angled mags except for the CZ-75 and Beretta 93R.

 

[Vern Humphrey]

Why is this a problem? Just about every semi auto pistol magazine operates in this way.

Submachine guns have much higher capacity than pistols. They therefore have much higher stripping pressure (try loading a couple of magazines for an M3 "greasegun" without using the stock loading tool, and you'll see what I mean.) The added burden of moving the cartridges horizontally under thta pressure would make them less reliable.