The .50 is a perfectly viable MG piece. Sure, it has bugs, but as a USF player I am used to having units made unviable and broken because of those.
The issue with USF, since Relic thinks that they are a glasscannon faction that has to be micro-heavy as a result
, is that you need to use your support weapons in a much more supported and deliberatly supported manner than any other faction does. USF mgs have less survivability than the mgs of any other faction (for obvious reasons), which forces you to play to your utmost to keep it alive.
The way Cookiez and I use our MGs is simple. We have RE squads spam Tank traps in wide "V's," then place mgs behind the furthest tank traps (with still enough range to hit VPs). This allows us to use the "closer" green cover to hold our rifle squads and RE squads, who spot for our mgs and tank the damage. It is these squads that also stop the point from being neutralized. Add 1 - 2 Pak Howies, and our little defense is finished.
With these tactics, you also need to micro constantly to avoid stukas and the like. But what else is new
? We have never lost a game without having bled the enemy VPs to below 150, and we typically lose because of a combination of bad RNG, shitty maps (Rhezev Ice on middle VP anyone?), or just general fatigue. Of course there is also the issue of dropping, but that is up to Relic.
Just remember that defense should only be a screen behind which to prepare offenses. Whilst one player holds the line, the other should be poking across the map.
Well shit, looks like I rambled about defenses in general, not the .50. Just use the .50 like a better Maxim. Rely on overlocking fields of fire and support to defend a position, and make use of it's fairly good suppression to make your infantry squads do shit lategame. Don't expect it to do what an MG42 can. The MG42 is ridiculously overperforming (same DPS as an M2 at long range, with higher suppression, lower cost, and incindiary rounds). The M2HB is merely performing.