strip the bolt from the carrier and slowly slide the carrier into the upper feeling for any resistance when the end of the gas tube enters the key. any resistance can be corrected by adjusting the barrel nut timing or bending the end of the gas tube inside the upper with a large flat bladed screwdriver.
Moderation is for monks. RAH It's a thankless job, luckily I have karma to burn. HEY YOU WASHINGTONIANS! http://groups.yahoo.com/group/wa-shooters