Ive been shooting MFX classics full length with 75 grain inserts and 150 grain heads thru my ACS
its 46# at 28" and Im pulling 30.5
The arrows were shooting staight with no visible propose or wiggle
They just would not group so I decided to bare shaft one and what I get at 10 yard is and almost sideways nock left shaft which I believe is telling me weak spine.
I have some Vapor Hunter 400 full length.
With these shafts with a 150 grain head they are flying much better and I started cutting 1/4" off at a time until they are flying straight.
Now I am getting a hard nock down Is this and indication of a low nock point.
I also plan on shooting 170 grain broad heads so should I also be tuning with 170 grains up front

QuoteOriginally posted by bucksakemmer:

I also plan on shooting 170 grain broad heads so should I also be tuning with 170 grains up front

Yes, of course! Otherwise you will get underspined arrows when you put more weight in the front. Arrows with broadheads should fly like the field points ones. Thus the weight in the front, the arrow lenght, the fletching, etc. should be the same for both.

The reason for your low nocking point indications is from the difference in dia. of the two shafts. Raise your nocking point and carry on with tuning.