Will a Unitized Gas System Enchance Accuracy?
The objective of this Thread is to provide information concerning the relationship between the Unitized Gas Cylinder System and the mounted Stock Ferrule as it effects accuracy on both the Match Grade M1A and the Modified M1A.
The answer to the Title question is, "seldom", and when it actually does, it's by chance. My personal experience in building Match Grade M1A's and M14's has shown that a Unitized Front Band/Gas Cylinder can be either an asset to accuracy, or it can be a detriment to accuracy.
To realize the potential of the Unitized Gas System, the Unitized Gas system must be mounted on the barrel when rifle is bedded. The method employed in the stock routing procedure must conform to the use of an "Inside barrel spacer fixture" if a vertical center line is to be established. If a Unitized Gas System has been added to the rifle subsequent to the bedding procedure it will most often result in vertical and horizontal disagreement with the mounted Stock Ferrule's bottom dead center and a loss of accuracy will result.
When the rifle is bedded, INSIST, that an "Inside Barrel Space Fixture " be used. This fixture prevents misalignment with the Stock Ferrule to a much higher degree than "Outside Barrel Fixtures". Center line agreement is maintained when the "Inside Barrel Spacer" is used because the Stock Ferrule and the Unitized Gas system, which are used to locate the barreled receiver assembly in the stock during the bedding process, are the SAME components used on the rifle.
If you have added a Unitized Gas system since bedding, take heart, this could be the reason to get a fresh bedding job. Personally, I use an alternative method on my M1A's.
By Art Luppino