I bought some 11/32 Zwickey Black Diamond glue on broadheads and the matching screw in adapters, I tried a dry fit on my Heritage 150's and they are a little wide. I am assuming I should have picked up the 5/16ths but they didn't have any at the local shop. Will it make a difference if I use the 11/32 or should I get the 5/16?

It is my understanding that if the shaft is smaller than the broadhead you get better penetration.

Matt,

It doesn't make a lick of difference. I'd wager that most guys (myself included) who use 5/16" shafts use 11/32" broadheads.

I use 11/32 heads on 5/16 woods all the time.  Works great and makes for less breakage at the head.

If the point is bigger than the shaft you're okay.  What you don't want is the shaft to be bigger than the point.

The 11/32 heads are also bigger and heavier than the 5/16 heads.  I consider that a plus.

You can grind off some of the end that goes on the shaft and it will fit better.