These are $700 guns. There is something terribly wrong if the headspace has to be checked! This is very poor quality on T/C's part. I believe I will trade it for another gun before I buy a headspace guage for it. It would be completely different if it was a $300 gun. Thank you for the insight.
The headspace thing is a big bunch of baloney. I've probably had 30 to 40 Encore and Contender barrels and various frames and friends have had them and there have never been any headspace issues. The person with the "making them work" song is a bit preoccupied with the alleged headspace issue.
My Encore 308 Winchester load uses IMR 4064 and 165 gr. and 168 gr. bullets. If you use match bullets from Sierra or Nosler in the load workup, you can eliminate the bullet as a cause of poor accuracy. If after having worked up what should be an accurate load you're still having problems with accuracy, I would return the barrel to T/C. The usual advice about making sure there are no problems with the scope or mounts apply.
Other powders to consider using would be Varget or IMR 8208 XBR.

How an Encore handgun shoots with full length sized brass (no, I didn't check for headspace or check the brass with one of those Wilson thingys).