I know this has been asked many times but I can't find it anywhere so please one more time. I just started shooting broadheads 125 grain 3 bladed Muzzy on the front of a 28"400 Easton ST Obsession. I am shooting a Hoyt Lazertec 64 lbs with a QAD LD rest. The bow shoots great groups with field tips and broadheads but the Muzzy's shoot 4 inches to the left. Adjust the sights , adjust the rest, what do you guys think? Thanks

I just ran your specs through Easton's arrow selection chart and it recommends either 340's with the 125's or 100's with your 400's.

In other words the 125's appear to be making your spine weaker than desired.

I'd bet your bow/rest is slightly off tune left/right. Any issue in tuning will be emphasised with broadheads. Perhaps being slightly underspined isn't helping the situation as DaveC has pointed out. Unless your seeking a higher end FOC, you'd be better off with 100 grain heads. If you have access to a laser tuner, you could check your center shot as well as the simple scale models that go in your limb bolts...if you feel you are where you need to be, slightly bring your rest in about a 1/16" and see where the Muzzy's are grouping compared to field points, another 1/16" may be required but be as close to center shot as you can be.

Have you done anything since this post?

Which is why I am not a huge fan of Muzzy's. They are deadly heads, no doubt.....but at higher speeds they can become quite tedious to tune. Not that it can't be done, though. The above advice is good.....See what happens.

Thanks guys for all your ideas and help. I lowered my poundage by 2lbs
recentered my arrow the best I could without specialty tools and checked nock point and arrow level. I am real close now, I do have one question, on the easton chart it shows the 400's underspined at 64lbs, but in their tuning manual it shows if you are shooting left it is from overspining. Thanks again Bob

Ps mobohunter I hunt up at Edina are you anywhere close?

The over or under spined chart is based on a correct center shot from the beginning when comparing with fieldpoints.
If your centershot was off to begin with the chart wouldn't be of much use.

Another thing. In Easton's Tuning Guide, read the next to last paragraph near the bottom right hand column of page 13. I don't think anybody ever reads this whole thing.

http://www.broadheadtests.com/TUNING.html