i am shooting muzzy 3 blades in 125, i still havnt completly sighted in my new bow yet, but i was looking at somthing and would muzzy's in 100's better then the 125's i am using????
thanks

depends on the spine of your arrows.

Definitely something that needs to be considered!!! Switching to a lighter head increases the spine and it could possibly make your set up too stiff. That being said, it is better to be too stiff than weak so you might be able to pull it off.

By switching to the 100 grain head you will also lose a little bit of FOC which could have an impact on your arrow flight depending on where you are at right now.

Finally, while you will pick up somewhere between 5-8 fps depending on the bow you will also make your bow louder by shooting a lighter arrow.

All things to think about and personally I am one that believes if it ain't broke, you don't fix it

well my arrows are spined at .500 my bow is at 54# and my arrow length is 27 inches. wouldnt that info tell me if i would be under or over spined?

I would shoot100 and 125 grain tips through paper and see if one tunes better than the other.
I believe the 100 is a more compact head, less wind resistance may equal better flight.

Better no, just as good yes. It really depends on your setup. For the most part your bow should tune with either and one will probably be "best" in terms of FOC etc and give slighty better accuracy with one over the other, but I doubt many bowhunters could shoot well enough to tell the difference. I normally pick my broadheads and then tune the bow to them. This year I will be shooting125's but I have had the same arrows tune and shoot 100 grn heads very well.

well the reason i went with 125 to begin with is because i have a short DL, and my # isnt quite as high as some. so i figured that i would get better pentration with the 125 then the 100's, honestly i dont want to switch cause i dont want to have to buy BH'sbut i was wondering if it would give me more accuracy.
thanks guys