I purchased some slides for the retractable group assy for the M2. However the 2 smaller threaded holes are oversized and will not hold the arm stop stud. I am thinking of just installing heli coils but I have to order the right heli coils. The threads measure out to be 24 NF but not sure on the diameter, I think they are 5/16 or 3/8. Can anyone confirm on some drawings that this hole is expose to be 5/16-24 or 3/8-24 ? or even take a stud to a sizing gage ? Also its been a while since I have installed a helicoil, what size tap would I use in the over sized hole to prepare it for the helicoil ?