You don't give us your draw length and draw weight, or what bow you shoot, or whether you shoot fingers or release (I'd guess release though), so it's kinda rough to give you any real help.

My best semi-educated wild@$$ed guess is, since you're shooting 50 lbs; since your arrows are only 30-50 spine to start with; and since carbons are notorious for getting their spine 'shot out', your arrows are underspined. I'd suggest going up to the next size shaft and using 100-125 gn heads.