One might wonder why I'd have to make an entire single trigger mechanism for a Boss, so I'll answer that question with another question: Just how much damage can a "stock maker", with absolutely no mechanical comprehension, actually do? The answer is: A LOT.
The gun came in with a complaint of doubling, which, if you understand a Boss trigger, is physically impossible as long as everything is as it should be. Therein lies the rub, as NOTHING was as it should be, because our woodworking hero had no idea of how much he didn't know (obviously, that was no impediment though).
It would seem that, for reasons known only to him, he decided that the angle of the lower tang needed to be altered. Now bear in mind that the Boss's rotary shift drum is mounted to the triggerplate (behind the trigger blade), while the sears are, obviously, mounted to the lockplates. When he bent the triggerplate tang upward, this altered the spatial relationship between the drum and the sears. It also altered the spatial relationship of the drum to its reset link and the trigger blade itself, because he bent the tang behind the triggerbox, which carries the trigger pivot and the slot for the reset bar.
Having now discovered that the sears no longer wanted to play nicely with the shift mechanism (because the drum is now higher, further forward AND at a different angle), he decided that the drum had to be lowered. He did this by removing material from the lower skirt of the drum. This was apparently only partially effective, so altering the sears was the next step in his "oh shit, now what" approach to gunsmithing. And alter them he did, multiple times, via bending, then grinding, then welding and so on, in that fashion. Eventually, he managed to get the gun back together (after a fashion) but his lowering the shift drum also introduced another issue. The Boss drum rotates on a vertical spindle, which has a projection at its top that meshes with a mating notch on the drum, in only one position. When aligned, this allows the drum to be lifted vertically by the trigger blade, raising the left sear tail and releasing the tumbler. The problem is, he lowered the drum but not the spindle as well (because there was no way to do so), which introduced a gap between the projection and the drum, sufficient to allow the drum to lift, regardless of its position. The result of that should be obvious. The reset bar also crashed the drum, and the spindle, so, naturally, he modified the drum to alleviate that, blissfully unaware of the consequences of that action.
But wait, there's more. Now that the sear tails are nowhere near where they used to be, the safety no longer works. The fix? Welding, the really good kind, with porosity and contamination. "That's alright", says our intrepid imbecile, "I'll just clean that up on the buffing wheel". Clean it up he did, to the point that the left interceptor, which is operated by the safety slide, now would slip out of its cam groove.
Long story short, a shit-show worthy of an Oscar.
Behold.
Making things right...
The right main and interceptor sears machined from O1 and heat treated to Rc60.
The new shift drum and spindle were also made from O1.
Unsurprisingly, our ham-fisted hero also managed to crack the shift drum spring through the inner hole.
I drilled a new hole adjacent to the original and reshaped the end of the spring.
Checking the spring's function...
I made the new reset link from 1018 and case-hardened it after fitting.
The safety slide was made from 1018 and case-hardened after fitting. Obviously, I also made new retaining pins as well. The nails were a bit too "rustic" for my taste.
At this time, I corrected the damage to the left interceptor sear. The video illustrates its proper interaction with the safety slide.
Naturally, an Alpha-dipshit of this level would never do a job without "marking his territory" via mangled screw slots but this guy went above and beyond by making a new breech screw, triggerplate screw and triggerguard screw. He apparently was unaware that the threads in a Boss are all BA-type though. Thankfully, the screws were apparently made of Home Depot's finest Chinesium and were so soft that the existing threads survived. He even engraved them himself.
Obviously I'd never let anything go out the door like that, so I made all new screws from 1020, engraved them in the correct pattern and case-hardened them. Why didn't I "heat blue" them? Because they were originally case hardened and, I'm not a hack.
Here's a video without the stock and left lockplate, showing the operation. The Boss trigger is a "three-pull" design, meaning that the recoil-induced, involuntary second trigger pull does nothing. The intermediate pull is not noticed during live-fire but is readily apparent during dry-firing.
The finished job...
The "Cliff's Notes" version...
