i recently got a used Outback for deer and turkey hunting. the bow came set up with everything but string scilencers. my problem is that my "zero" keeps dropping. last week i was shooting at 40 yards and was hitting the 10 ring consistantly. i was shooting today and my 40 is about a foot and a half low. i have a single pin HHA sight and i know i am setting the sight on my 40 yard mark. idk what could b causeing this.

Your string could be stretching or your arrow rest is dropping. Both causing the point of the arrow to start out lower than your original zero. Re-check your arrow's nock height and rest mounting screws and re-zero your bow.

Or it could be as simple as the nocking point sliding up the serving---or the center serving slipping up the string.

Ditto what both the above guys said!!!! What kind of rest is on the bow??? The NAP QT2000's are notorious for this!!!!

they both could be right or ur sight could be moving or moved when u sat it down if it was not tight

Walks and BG are giving you some very good things to check! Let us know if you get it worked out.

Dan