The Type 115 rifle in Apex is interesting, but I don't see the point. Many users that comment on this weapon seem to share the sentiment, the .50 cal underslung portion just doesn't make sense and is fairly unrealistic.
A short barreled, low velocity .50 cal doesn't provide anything that a 6.5mm assault rifle doesn't already provide. Their roles overlap too much. You could pepper the windshield with the 6.5mm rifle portion to take out the driver or shoot out the tires, both of which are easier to accomplish with an automatic 6.5mm than the underslung .50.
For what the .50 can do that the rifle portion of the gun can't, namely destroying car engines, slugs fired from a shotgun would serve the same purpose. Which brings me to my next point.
The in-built underslung weapon on the Type 115 would be a perfect candidate for a shotgun, and would require almost no graphical changes to the weapon. This would provide the flexibility to the Viper special forces teams that have been talked about, and is perfectly suited for a jungle environment. Buckshot, Slug, and Explosive ammunition types would allow for a range of options depending on the mission.