What kind of release are you using?

I shoot a Diamond Hornet that is 30.5" ATA at a 28" draw, and up until recently I shot with a Tru Speed Nock above the nock, and my scott mongoose directly on the string below the nock. I had no arrow flight problems whatsoever.

The Speed Nok has a radiused edge to prevent nock pinch. My guess is you are pinching the snot out of your nocks, as well as releasing the arrow tail high due to the nock set up.

If you can adjust your release to accomodate for the added length, a string loop should do wonders for you. If not, you' ll have to adjust your anchor point farther back a bit to use one. This may or may not cause problems, depending on your current form. I would recommend string over a metal D loop, as they gain nothing but add considerable weight to the string, costing you transferable energy and fps. I' ve even seen reports where they' ve whipped forward and cut guys arms.