[Alan Ebright]

Here’s an update on my SST 28ga. Gun was NIB purchased Jan’24. Came with original purchase receipt. Was worried about shooting 40yr old gun that had just been sitting in its case, so I called a couple of proficient smiths and they said to go shoot it and see. I put 750 3/4 oz. loads through it over a 5 month period. It doubled on me twice in that period. Then one day after firing both barrels, it locked shut. Finally opened it after it cooled down, but then only 1 barrel would fire. If I switched the selector to the other barrel, only that barrel would fire. However, when the snap caps were in, both pins would go. Strange?
Found a talented gunsmith from a guy in my SxS group, and he diagnosed it over the phone. Took it to him and he fixed it in 15 mins.
It was the inertia blocker (counter weight) in the trigger assembly. Looks like two tiny pendulums that sit right next to each other. The inertia blocker exists because anyone firing a single trigger inadvertently pulls it a second time from the recoil. It’s there so the gun doesn’t double. They needed to be lubed, simple as that. The inertia system doesn’t engage when dry firing or using snap caps.
FWIW, the smith told me the Parker single trigger is actually a well made assembly and it just needs to be maintained. He knew of no design flaw leading to doubling problems. He’s been in the biz since ‘81 and seen plenty.