Single trigger identification
 

Can someone help me identify which single trigger I have? Almost positive it's a parker but not sure which version. It started doubling on me so I wanted to see if it maybe just needed a good cleaning. Actually looks pretty clean. So who knows what's going on.

It is not a Parker trigger. And it is not one of the more well known aftermarket types either (ie: Miller, Infallible, etc...)

I am not sure what it is.

But we have seen that selector slide before.





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I honestly don't think the trigger mechanism itself is the cause of the doubling as the way it's designed, there is no way both hammer sears can be tripped at the same time. I honestly think the sear engagement on the hammers may be set too light and recoil is causing the doubles as it will not happen with snap caps or .410 tubes in the gun. The trigger pull is quite light for a shotgun. I'll pull the sears out tonight and take a look at them.

More pictures of the layout of the sears.

What we call "doubling" is almost never both sears coming out of bent at exactly the same time, but often the recoil from the first shot tripping the second barrel's sear. The reports are very, very close together and some inexperienced folks think it's both barrels at once. Another rarer, but possible cause is that the involuntary second trigger pull that we all do upon recoil is not being "accounted for" by the trigger, and is actually causing the second barrel to fire. This is a feature that is built into the trigger itself. Robertson and Adams, at Boss, developed the first mechanical single trigger that overcame this "involuntary pull" in the early 1890s. All successful mechanical single triggers have some method of accommodating this phenomenon.

In an inertia-shift single trigger the trigger is briefly disconnected from the sears altogether, and the involuntary trigger pull takes place during that brief time, to no avail. So, instead of the second sear being temporarily blocked, as it is with a mechanical single trigger, it is merely disconnected for a "split second".

I often to my own trigger work on rifles, pistols and some double trigger shotguns, but I don't mess with single triggers on doubleguns. Phillip Crenwelge, or Don Rackley, both in TX, handle that quite nicely for me.

After removing the sears and comparing them to an original set of sears I think I found the reason it's doubling. The sears with the single trigger don't have the small relief ground on the "belly" to allow proper engagement on the hammers. I thought the trigger on this gun felt very light, and that's probably why. Also explains why it won't do it with snap caps or 410 tubes. The recoil from heavier loads are jarring the second sear enough to let loose. I will add the relief in the sears and see if this fixes the issue. The pic shows the single trigger sear on the bottom compared to an original sear on the top.

I hope you keep this discussion going. Very informative and helpful.

I dont think that cut, or lack thereof is making a difference. Proceed with extreme caution if you do anything. You may be doing irreparable damage.

If the trigger was working, I wouldn't make any drastic adjustments. It might be something as simple as dimensions between upper and lower tang not allowing clearance for trigger to work, sear drop, or engagement. Better to send it to someone now if you're not sure. Any incorrect changes made will make it more difficult to be fixed later and cost you money.