Davidmil said It pretty good. I like a heavy set up myself so I'll take the 125's+ any day of the week.

I'm with Steve on this, give me the 125gr any day of the week and make it a Snuffer! I also use a 50gr Brass insert to beef up my arrow weight up front and total arrow weight. I always say, it's pretty hard to stop a speeding Freight Train!

I like both, but I get better arrow flight out of a 125 than a 100. And that is because I'm just a hair overspined with a 100 vs. 125, or at least I believe that. I put a 125gr ST Mag completely through the spine and through the chest of the "disabled BB" I shot this year, and with a little re-edging, it was back in my quiver and ready for service!!!!

Thanks for all the help guys. Everything said makes sense and I will do a little experimenting on the off season.

Reference this post on FOC for some more insight.
http://www.huntingnet.com/forum/tm.aspx?m=3255126

I have one arrow with 100 grain insert and 100 gr Thunder head the others have the insert and 125 muzzy Phantoms.the lighter hits just about 1 inch high at 20 and I haul it just for varmints and the such,but it flys true enough that I wouldn't think twice about launching it at a deer!

I always tune the arrow to the bow by weight. When I get a new size of arrow I go out and shoot 80,100 and 125 gr. points and see witch group the best at 50 yards. On my 400 axisout of 70 lbs and 28 inch draw 80's shoot OK and 100's group the arrow on top of each other and 125 my group reallyopen up. My 100 gr. Montec really group great at 50 yards' I can shoot them into a 3 inch spot all day long and for deer hunting the blow through the bucks I have shot like they are a card broad box and stick the arrow in the ground. Shota mature buckthis year at 25 yards in the paddle bone on exiting. It passes through and still stuck the arrow in the ground with no damage to the arrow.