If you drill a small pilot hole in the tang & one in the triggerplate, then drill thru them with a drillpoint jig you will not have that wallered out hole that you have at the triggerplate. You drill halfway down thru the tang, turn it over & drill the other way from the triggerplate to the tang & the holes meet in the middle (hopefully :redface: ) Then you install the tap down thru the tang & thread the triggerplate & quite carefully taping & backing out allot as not to break the tap. I would leave the hole alone and go on, really not a issue & is covered up.
On the lock bolts, I suggest you drill pilot holes & then a drillpoint as it is important you line these holes properly & not alot of room for error on the lock bolts. And you will break the tap on the rear lock bolt hole in the bolster Much easier than the last hole.
Get the holes drilled thru, again use the drillpoint and drill 1/2 qway, turn it over & drill 1/2 the other way, then put the tap thru the stock into the lockplate & start the tap so you know it is started well, then take the tap out & do the other hole same way, thrn remove tapagain & take the lockplate out of the stock & put it in the vice horozontal & put the tap back in my hand the way the threads take it,(NOt how it Looks, but how it is cut as it may not be exactly 90 deg) now use some Thread Tapping Oil and cut tap out the threads, using LOTS of backouts on the bolster part where it is thnick.
My theory on tapping, just when I feel I need just a "Little More", that is when you stop & back the tap out til it Feels clear & not binding... If I do tht Little More, that is when I break the tap.
Just a big spike ground to a point, clamp in a drillpress vice, clamp the vice to the table with the drill & the nail point centered, you have a drillpoint jig in 2 minutes......