A true gunsmith with a mill can do it easily. Talk to fellow shooters in your area. Make sure the smith has done before, you don't want to be the experiment.
Good luck.
This is not a USPSA problem this is a local problem. In my area we have 25-35 yd targets in every match. Seldom have movement more than 15 yards without shooting. If your local club puts on a crappy match shoot elsewhere or step up and help run a better match.
The hammer will not fall when you pull the trigger on a flagged gun. The disconector de activates the trigger from the sear unless the bolt is fully in battery.
If my memory is correct his main gun went down just before match and he showed up with a single stack 38 super iron sight comp gun and Finnished in top 16 possibly top 10. Was at match but was a long time ago.
One of the best things about USPSA to me is unlike any other sport anyone can put thir money down and compete with the world's absolute best on an even playing feild.