I switched to 3 under a few months back and have been loving it. It seems much easier for me to keep tight groups right where I want them at hunting ranges. I still shoot instinctive and have the same anchoring point so the change was easy.
Anyway, I have been getting a slight porpoise in my arrow and I couldn't find out why. It was just slight and my broad heads were still hitting with my FP's. Today I added a tied on nock below the arrow and everything is solved! My arrows are flying perfect now!

That's what you call an "AH HA" moment.    

good call on your part!

all my bows shoot better with 2 nock points.  The videos that show the arrows sliding was enough to convince me to add it

QuoteOriginally posted by sawtoothscream:
  The videos that show the arrows sliding was enough to convince me to add it

I've heard of this video but haven't seen it. Anyone have a link to it? Is it a YouTube or what?

http://picasaweb.google.com/116451859615119061133/AVIs?gsessionid=7mSKL-zaMfFf3Mgrd36Iog

It was posted on here not too long ago... someone should make sure it's in the video section

I always use two nocking points to prevent the arrow from sliding down the string.

Two nocking points is the only way to go.

How far down do you put your lower nock to keep it from pinching the arrow?

Battman... you only need about a 1/16 space. Any more defeats the purpose.

Success!!!!!!!!!!!

Thanks

Thanks for the video. I'm convinced. Will be using two from now on.

Does this only happen when shooting 3under?

I shoot split finger and added a secound nocking point and it seems to be grouping better( I just have to  retrain myself to look/feel to make sure I'm nocked between the nocks not under the lower.On the lower I used a differant color (white)serving to make it easier)

It can possibly happen any time you nock under the point. Nocking above ala hill style can sometimes be enough. It all depends on the person.

Tenbrook... it can happen with either style.