t could have it's place, but I could never see it being put back in. Many people tried to pick it up in .5 to be 1337. (Remember those Barret kits with duel Uzis? Wasn't that wild?) I would check around with the rest of the modding community thoughl.
Who knows

? maybe they have been removed cause they were inappropriate for the maps they stood.
Bi-ming ; Ghost train : Forest maps, nobody on heart would choose a .50 sniper rifle on such battlefields (I know... someone just did it in Rambo IV :roll

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Al basrah : view distance <500m was too low for this rifle to be used for extra long range sniping.
Kashan : that was actually the only map were the rifle was close to justified, although the regular 7.62x51 rifle can do the job.
I've read an Afghan map with view distance >1500m was currently WIP.
Since :
the .50 sniper rifles have actually been used for anti-infantry roles in A-stan IRL
the .308 ingame becomes hardly useful due to bullet drop/loss of damages over 900m.
Maybe the devs will consider a comeback for them, at least for a few maps. I think you can set different kits layouts depending of the map, at least they did it in earlier versions (you had a shotgun for the engineer on CQB maps and an assault rifle on others).
Don't get me wrong, i'm not calling for the comeback of the .50 sniper rifles in-game or anything, I'm a **** shot and pretty much never use them anyway. Just to make simple suppositions

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Many thanks to everyone involved in the making of the best videogaming experience ever !