AK is not so much "rugged" as it is reliable Kalashnikov designed the mechanisms with ample clearance -- making them easy to manufacture, assemble, interchange, and use. First receivers were milled from 4.5 lbs of steel, and the Bulgarian receiver is still milled steel. Bulgarian reciever has distinctive wide, flat "scoops" in each side, making it easy to ID in photos, etc.
Heavy stamped sheet metal receivers on the AK are strong enough, but mostly they're fast to produce in a less than high-tech manufacturing plant. Because the gun is loose, it functions even when full of dirt, mud, blood, crud.
Chrome lined bore was intended to prevent corrosion when using corrosive ammo. But chrome is a nice feature in a battle gun because it's durable.
Success of the AK is that it is cheap and fast to produce, simple to operate and maintain, requires minimal maintenance. You want these features when arming a third world nation of illiterate peasants.
When taking over Saigon, Viet Cong troops were using AK's that had been buried for years . . . wood stocks had rotted away, and so the rifles were wrapped in rags.
-- Stoner's AR-15 by comparison, needs constant maintenance, is closely machined and failed in Viet Nam regularly until Dept. of Defense developed BL-C-2 powder that wouldn't gum up the gas system.
Desert Eagle is massive, but prone to jams and gumming up. It's a gas operated rotating bolt system in a handgun -- using ammo designed for a revolver. Hard to engineer a gas operated system on a handgun scale.
Rugged . . . I'd say the Mauser bolt action rifle. These receivers are still coveted for building custom rifles.
Walker pistol -- designed for Gen. Walker's troops as a "repeater" for mounted troops is a rugged gun. Until the development of the .357 magnum, the Walker was the most powerful handgun. "Outlaw Josie Wales" uses a Walker -- Eastwood's debut as the "big gun guy."
Thompson Contender is rugged. Few moving parts, single shot.
Ruger No. 1, single shot, falling block "Farquharson" action is used in the heavy caliber guns for African Dangerous Game. The Farquharson design developed in the 19th cent.
Here's "rugged" . . . No moving parts unless you count nuts on bolts or rings in eyes. 1" bore, 20" bbl. 3/4" wall -- seamless high pressure steam pipe.
Carriage is built from white oak John Deere tractor pallets. Gavanized fence hardware from the feed store . . .
Bbl. weighs 22 lbs. Carriage weighs 15 lbs.
Shoots 3 oz. lead ball w/ 500 gr. black powder. That's a 35mm film can full. Smooth bore. I don't worry much about rust/corrosion.
) The one Desert Ego I've fired proved to be a very finicky eater. Oddly enough, it was the WWB it liked, and not the more expensive brand that its owner brought along. I suspect the most rugged gun I own is my Stevens single-shot 20 gauge.
:banghead: 
