I have PTR-91 than when new headspaced at 0.017 in.  After 700 rnds I am now down to 0.013 in.  I measured the headspace at the following approx. round counts:

0 rnds - 0.017
100 rnds - 0.016
300 rnds - 0.015
700 rnds - 0.013

Curious about other people's rifles, how much their headspace has changed on a new rifle.  Should I give it some more time and see if it stops, or do you think a call to JLD would be in order?

I wouldn't worry until it get to or drops below .010".  Then give 'em a call.  Acceptable "spec" is from .020" down to .005".

.013" might just be where your gun "settles in".  

My 2 cents.