Before beginning accuracy work, there are a number of basic negatives that must be corrected.
1, Barrel / receiver misalignment...... Flat flash suppressor sight mounting platform parallel with horizontal centerline of receiver.
2, gas cylinder and flash suppressor vibration or movement......upper splines should be peened on both sides in order to ensure a tight fit.
3, gas cylinder port and barrel gas port misalignment........use the tool..if ya don't have one ya should get one....also shims if necessar (although opinions on this differ)
4, op rod, dragging or binding.....check op rod for straightness and allignment. (Check op rod guide for tightness too
)
5, Handguard interference....slapping of the handguard against the stock can cause changes in the barrel. Make sure that there is a clearence of at least .010"
For an in depth description I would suggest purchasing this book.....It has been extremely helpful to me
The U.S. .30 Caliber Gas Operated Service Rifles- a shop manual volumes I and II by Jerry Kuhnhausen
http://www.bookfinder.com/search/?st=sl&ac=sl&qi=9rJzenZDSRM1ho54prjaGkQ9rJzpaYja:329:630
1, Barrel / receiver misalignment...... Flat flash suppressor sight mounting platform parallel with horizontal centerline of receiver.
2, gas cylinder and flash suppressor vibration or movement......upper splines should be peened on both sides in order to ensure a tight fit.
3, gas cylinder port and barrel gas port misalignment........use the tool..if ya don't have one ya should get one....also shims if necessar (although opinions on this differ)
4, op rod, dragging or binding.....check op rod for straightness and allignment. (Check op rod guide for tightness too
5, Handguard interference....slapping of the handguard against the stock can cause changes in the barrel. Make sure that there is a clearence of at least .010"
For an in depth description I would suggest purchasing this book.....It has been extremely helpful to me
The U.S. .30 Caliber Gas Operated Service Rifles- a shop manual volumes I and II by Jerry Kuhnhausen
http://www.bookfinder.com/search/?st=sl&ac=sl&qi=9rJzenZDSRM1ho54prjaGkQ9rJzpaYja:329:630