Like the others said Chuck, a string loop has nothing to do with arrow length. It will effect your over all perceived drawl length, but the actual draw length of the bow does not change, so the arrow length should not either.

If this is problem that wasn't there before have your bow checked to see if something didn't change, like a string stretched or something moved on you. Or possibly if you got new arrows they were not cut to correct length.

The end of your shaft (not the point of your tip) should be one inch in front of where your arrow contacts the rest. You might possibly be able to move the rest back a bit if you have to, but would rather see you get the correct length arrows or possibly shorten your draw length. Most shoot too long of a draw length anyway. That would have to be something to have someone with some knowledge check though. They would need to watch you shoot.

Paul