Weight may possibly be the issue, unless your old ones are MX-3's. They don't sell them in a 6-pack so your new ones are standard. I was using 100 gr 3 blade Muzzy's, but went up to 125 gr. The 125's seem to fly a little more consistent for me, and I am a fan of weight. I realize that doesn't have anything to do with what you are wondering, just thought I'd throw it out there.