Hard to get a "true" double with a DT gun by slipping from the front trigger to the back.
left handed...hot barrels it's not real hard.
By a "true" double, I mean a virtually simultaneous report. You can't move your finger fast enough, from one trigger to the other, to do that. Those that have been around guns that have doubled will have observed one big boom (true double), as well as a very fast boom-boom, two distinct but very rapid reports. Unless you have two fingers in the trigger guard and pull both at the same time, the one big boom isn't going to happen as a result of anything you do with your trigger finger, on a DT gun.
Re Jones' test, all you need is the snap cap, and you don't need to examine anything. After you've pulled the front trigger, pull the rear. If it goes click, the gun would not have doubled had that barrel been loaded with a live round. If that hammer dropped (slack trigger when you pull it) and you're sure you did not slip back to the rear trigger, then you've likely got a sear issue.
