I shoot the Muzzy 3 blade 100's. I used to use the 4 inch flech and switched to the blazer. I think they actually shoot better with the blazer. I'd recommend double checking the weight of them, if they still shoot different than just pick one and sight it in and stay with that.
Good Luck

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.

If they are the same, they should shoot the same. Be hell to have to adjust everytime you put a new head on. Something isn't right with the heads....

ok, well i went out today to sight it in with the new ones. took a couple shots first, and for some reason it was right on. WTF? every once in a while now it still shoots off. not sure what went wrong? something with my bow? or maybe just my focus was off since it was off so far the first time that i wasnt concentrated enough? im not sure

If it lined itself out it was probably something you were doin wrong with your form or grip. It don't take much to throw you off. Good Luck

you got me worried now I bought some new ones and did not think about checking them. Figured on just using the old ones for practice. I guess might need to check them.

thats what i did then i decided i better just shoot a new one to see and thatys when it went off.

im thinking now though that it must have been just me because i havent touched a thing on my bow and the new ones are shooting good. i think the new ones just magnify problems with my form or my shot when i get tired or shaky.

All I have ever shot is the Muzzy 3 blade 100gr.. I switched from 4in vanes to blazers and my groups tightened a lot! Then I put a 3 degree Helix on my blazers and have the tightest group I have ever shot.. (Not that I would ever take the shot, but I am sighted in at 50 yards, 4 arrows in a 1in circle with the broadheads!)

I shoot Muzzy 3 blades with regular vanes with not too much trouble. A buddy shoots blazers and couldn't get them to work. Had to go back to regular vanes and worked just fine.