Not to be a jerk, folks, but when someone with actual combat experience using a 0.50 MG, like CWMV, speaks, unless you have equivalent professional experience with the same or similar weapon, you sit down, shut up and take very detailed notes.
If I'm correct, the XM218/GAU-15/A used by U.S. and allied forces is just a variant of the infamous "Ma Deuce" which U.S. forces have used since 1918. While modern versions are lighter and have better sights, and versions mounted on ground vehicles have a lower cyclic rate of fire than aircraft mounted versions (during WW2, the AN/M2), it's basically the same gun.
Given that there's a serious lack of U.S. WW2 era pilots on this forum, I'll take CWMV's word as close to gospel regarding the behavior of the 0.50 MG, with the understanding that WW2-era M2 0.50 caliber Browning MGs were somewhat heavier and had probably had a higher rate of fire than the versions he was using.
In any case, if you've played IL2 long enough and have read the intelligent posts about the effectiveness of 0.50 caliber guns on other forums, you'll know that the 0.50 is great for exactly the purposes the CWMV describes - taking out lightly armored targets. Given that U.S.A.A.F. fighters and ground attack planes mostly hunted fighters and unarmored ground targets during WW2, the AN/M2 was the perfect solution for their needs. It was fast-firing, reasonably reliable, had a fair bit of ammo, a high muzzle velocity and packed a decent punch.
By contrast, the Soviets and Germans didn't like the 12.7 mm/0.50 caliber MG so much because their targets tended to be bombers or armored aircraft (in the case of later war German fighters) and heavier ground armor (in the case of the Soviets). Part of the reason that the Soviets didn't particularly like the the P47 and P40 was precisely because those planes lacked cannons. Likewise, the reason that they loved the P39 Airacobra, and its successor the P63, is because those planes were equipped with 20 or 37mm cannons.
So, in the game you use the 0.50 as it was intended to be used. You only shoot wing-mounted 0.50 caliber guns when you're at the correct convergence for your guns, only when you've got sufficiently low deflection that most of your rounds will be on target, and only when you've got a shot which allows your to concentrate your fire on a vital target. If you can do that, and your gunnery's good, then you can rack up an impressive score of fighters or other relatively light aircraft without using unlimited ammo. If you're hunting bombers or heavy ground targets, you use a plane equipped with cannons or load your plane with rockets or bombs. (That said, to be fair, IL2 doesn't allow you to set the convergent of each pair of guns in your wings. Many WW2 U.S. pilots set the convergence of each pair of guns to be slightly different so that their chance of hitting something was higher. A better tactic, though, is to just set your guns for a single convergence point and learn effective deflection shooting. Unlike real WW2 pilots, you can spend endless hours just practicing gunnery. . .)
As for bigger prey . . .
A shredded bridge wont change its speed or course or general behaviour.
A shredded bridge sure as heck will alter behavior if you kill the bridge crew and turn the wheel, binnacle and communicators into scrap. A dead man at the helm might not make the ship alter speed, but the ship could easily fall off its course if there's nobody at the wheel. Also, nobody on the bridge means lack of coordination with other ships, more poorly coordinated damage control and lack of coherent command over the ship's movement and tactical behavior. That's the reason that warships have secondary bridges.
But, as HundertzehnGustav points out, as it's a weak point of the IL2 game engine that ship damage and behavior isn't well modeled. There are mods which make it possible to damage certain ship subassemblies, like AA guns, with 0.50 MG fire, but it isn't possible to model different armor/hull thicknesses on different parts of the ship. Nor is it possible to model "critical hits" like wiping out the bridge/bridge crew, uncontrolled fires, flooding, exploding magazines or destruction or failure of vital systems such as communications, steering, electrical power, aircraft catapults, etc.
Likewise, it's a known fact that it's impossible for ships in IL2 to have AI in the same way that aircraft do. That means that ships in IL2 can't use "intelligent" behavior like zig-zagging when threatened by torpedoes, circling to avoid bombs dropped by heavy bombers, and collision avoidance. Perhaps it's possible to give ships such capabilities, but it would be a huge coding effort.
If we're very lucky, perhaps we'll attract the attention of a programmer with way too much time on his hands and an obsessive desire to upgrade a relatively minor aspect of a 10 year old sim.
