Since I am very happy wit the Jewell trigger in my B14R, I felt confident enough to grind away the rivet heads and open the stock Bergara trigger to have a look inside. The first picture can be used as a reference, second picture I assembled the top trigger spring the wrong way! Anyway, this...
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Some pictures for you to look over. Winchester calls their enclosed trigger “MOA”. I think they were the first to go this way although I liked the original triggers. Hard to find much detail about Bergara.
You mentioned Rise (I like the one I have in my AR). Too bad they don’t branch out, but anyway, lots of replacement triggers assemblies out there. Jewell is mentioned in these threads. I’ve always been quick to replace a trigger group with a high quality one. One of the fastest ways to shrink groups.