For the purpose of this test "light finger pressure" is defined as 8 1/2 to 8 3/4 pounds.
8. Check headspace by pressing key and bolt carrier assembly (5) and charging handle assembly (4) forward using light finger pressure.
9. Bolt should not rotate to locked position. Key and bolt carrier assembly (5) must protrude from rear of upper receiver assembly (6) for proper headspace. If excessive headspace, first replace old bolt assembly with an unused bolt assembly and then recheck. If headspace is not corrected, replace rifle barrel assembly; then recheck with the original bolt assembly to determine if the bolt assembly is still good or if the bolt assembly should be replaced also.
10. Remove key and bolt carrier assembly, bolt assembly, charging handle assembly, and headspace gage.
11. Reassemble rifle, refer to page 3-77.
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