An M2 Browning is wholly unrealistic and I would never condone its use on a figure.
The problem is what to suggest. An M240 could work, though it's more of a company piece as opposed to a fire team. The M60E3/4 is a bit outdated. There's only one PKM in the scale, and it sucks, and the MG3 is better than everything I listed but just wouldn't look right. I guess at the end of the day you've gone with the best thing available.