The explosive version would be too OP combine with secondary GL
Probably a under barrel shotgun would make it better than the under barrel GL
But you can make it work
Make it so the projectile is slower and it bounces once before exploding
But if shot directly at the enemy it one shots all the time
Downside if shot close range the projectile doesn't explode
It needs to travel a certain distance to explode
Another downside is when it's equipped ads speed is reduce by 25% and MS penalty of 5
And more recoil
And it can only be mounted on some rifles
Or scratch all that and just make it a incendiary rounds or a smoke round
Or flash can work too