LIKE id SHOOTING SAID..
ARMY TM-9-1005-249-10
3-9. REASSEMBLY OF M16/M16A1 RIFLE (CONT).
BOLT CARRIER ASSEMBLY AND CHARGING HANDLE ASSEMBLY (CONT
4 Stagger gaps in bolt rings (5) to stop gas
loss.
AND... on page 3-10
TROUBLESHOOTING (CONT)
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
8. WEAPON HAS SHORT RECOIL.
Step 1. Gaps in bolt rings (not staggered).
Stagger ring gaps (p 3-42).
Step 2. Carbon or dirt in key and carrier assembly or on outside of gas tube.
Clean (p 3-34 and 3-30).
9. BOLT FAILS TO LOCK AFTER LAST ROUND.
Step 1. Check for dirty or corroded bolt catch.
Clean (p 3-38).
Step 2. Check for faulty cartridge magazine.
Replace (app B).
10, SELECTOR LEVER BINDS.
Check for not enough lubrication on selector lever (l).
Lubricate with CLP (item 1,
For those who were not issued a copy....
http://pdf.textfiles.com/manuals/MILITARY/united _states_army_tm_9-1005-249-10 - 11_may_1990.pdf