ORIGINAL: shrewbeer
Its either a bad string job, or just you shooting different with the loop. When i switched I had to get a new anchor, new draw length, re-tune, and get used to it.
Easy way to test- IGNORE THE LOOP! Shoot your bow like you did before, and ignore the loop. If you are still shooting terrible, you know that its not you!
Yes, this is exactly what I went through as well. I switched to a d-loop back in 2005 and there was an adjustment period. I ended up shortening my draw by 1" and finding a new anchor and retuning. Now that I use the loop I can't imagine going back.