After 75 plus shots, I sent mine back to be checked 2 weeks ago. Would not come close to a group with any powder,sabot combo. Also had a "washboard" barrel - sabot would start easy, get hard, easy and hard to seat.
My feelings? - A $500 plus gun should not leave the factory with a barrel like this or need to be lapped to shoot right. When returned, I will shoot it enough to see that it is fixed, take a loss and send it down the road.

Steve