I found this same page seconds before that post.
This one line should help.
I know nothing about firearms except what the wounds look like after they are fired but I assume DA is for double action. I don't know what that means but I found those 2 words together on another page.
This, trigger stacking is essentially "stacking" more resistance against the trigger the further back you pull it until, boom.
"Double-Action" doesn't really make much sense until you study the history and progression of firearms, before the existence of DA guns the shooter had to nose the hammer back in a "single-action" before releasing it with the pull of the trigger. Muskets had a hammer that had to be noseed before triggering it to strike the flint that would make the ignition spark. The first revolvers were single-action, where before each shot the shooter needed to nose back the hammer, which also "revolved" the chambers. Then somewhere along the line, this nifty concept of the double-action trigger, which didn't require the shooter to nose the hammer back before each individual shot, a simple pull of the trigger and it would automatically nose the hammer back and revolve the chamber (and an empire was born). This invention however also introduced the best example of a stacking trigger to the world of firearms, as it required a fairly long stroke (comparably) of the trigger that gradually increased with resistance as it noseed the hammer back to its firing position, at which point it has been pulled far enough back that it releases the sear, and boom.
Well , this is what I got today and I read that it said the the trigger stacking was not bad at all .So Masherbrum I think your on the right track . Have not shot it yet .
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Congrats indeed! Purty gun you got there. I'm assuming it's double action only or is it DA/SA?