Here ya go:
To remove the trigger action from the receiver simply remove the "starred" screw behind the trigger guard. Use the proper size screwdrive and once you "break" the screw free, it comes right out. Then simply lift the action clear of the stock. It will be very tight but it does come out.
Grinding a screwdriver is precisely what I did for the front barrel band. I also hardened it after that using a quench bath so that the little tines didn't bend or break off.
As for the gas "regulators", if you can shoot your rifle without one, leave it that way. I've talked to two individuals about modifying my NATO MAS and they both said if it shoots good without it, leave it alone. If, however, you've got problems like poor cycling and chewed up brass, then send you rifle out to be modified. It isn't that expensive.
As with any old milsurp ammo out there, there are wide differences in loads. Some NATO ammo is hotter than others. I shoot only the Portuguese ammo in mine without a hitch. Experiment around before you have the gas system altered yet again unless you're also having shells stick in your breech or something catastrophic like that.
Hope this helps.
