Doubling of Parkers isn't THAT unusual. I have one that did it a number of times before I fixed it by honing the worn sear end to a better 'point'. Mine would double when the recoil of shooting the left bbl first would jar the sear on the right bbl enough to release it. Generally the right barrel gets shot way more than the left barrel so the sear wears quicker. It was a pretty simple job to jig it and touch up the point on a fine diamond stone. The left bbl sear was still fine. Whenever I buy another Parker I cock it and slap the bejeezus out of the receiver on all sides trying to get it to go off just to see if it's worn enough to do so.
