ANY size ball python above a hatchling doubling it's weight in 6 weeks is VERY unhealthy.
Slow down on the feedings.
Ball pythons "retain" roughly 30% of the food they consume, so in order for your animal to have gained 300g in six weeks, you've offered it ~1000g of food. Considering a 300 gram animal eats maybe 50g meals (a responsible, healthy size meal), you've offered that snake ~20 meals (or three feedings) a week?!
Slow it down or you're going to kill your ball python wth love (and obesity-related heart issues).
Good luck.