Step 4: Push both pivot-pin and takedown-pin left to right until stopped by detent. Separate upper from lower receiver.
Step 16: Lubricate and reinstall the charging handle and bolt carrier assembly into the upper receiver.
Step 17: Reassemble upper and lower receivers. With the rifle closed and the bolt in closed position, the piston assembly should have approximately 1/16 of an inch of forward to rear travel.
Step 18: Charge the rifle several times and check for function. Bolt carrier movements should be of normal resistance.
Step 19: Reinstall top and bottom hand guards or rails.
Check the bolt carrier for smooth operation and you’re finished! Enjoy your new Osprey Gas-Piston System!