Check For Worn, Out-Of-Spec Gas Cylinder
Helps determine the cause of unreliable cycling or if the gas piston must be replaced with an oversize head. A precise reproduction of the original ordnance gauge, 1005-222-05, that lets you easily determine if the gas cylinder mouth, or power stroke area, is out of round, or worn beyond specifications.
Big Book Catalog, Issue:68, Page:504
New Product Supplement, Issue:552, Page:008
SPECS: O1 tool steel. Hardened to RC 60.