My Gun is having issues firing BBs - Troubleshoots

BBs are rolling out of the barrel. 

(List is categorized from Easy to Hard Troubleshoots)

Issue: Incorrect hop-up adjustment
Fix: Check the hop-up setting. Turn it down or off and re-tune the settings to ensure proper function.

Issue: Dry Bucking
Fix: Spray 100% silicon oil into the hop-up feeding tube. Fire a couple of rounds to spread oil.

Issue: Torn Bucking
Fix: Remove hop-up and look down hop-up chamber side to check for issues. Nothing should be sticking inside the barrel besides the nub from the top down. Remove inner barrel and bucking to replace.

Issue: Broken Air Nozzle
Fix: Take the upper receiver off the gun to inspect the nozzle
movement. It should be reciprocating when being fired. If no movement, gearbox needs to be opened to replace it.

Issue: Broken Tappet Plate
Fix: Same inspection as “Broken Air Nozzle”. If no movement, gearbox needs to be opened to replace it.

Trajectory/Accuracy is not normal.

(List is categorized from Easy to Hard Troubleshoots)

Issue: Incorrect hop-up adjustment
Fix: Check the hop-up setting. Turn it down or off and re-tune the settings to ensure proper function.

Issue: Inner Barrel Dirty
Fix: Using a cleaning rod with a shop towel or cloth pad to swab the inner barrel for dust and debris.

Issue: Dry Bucking
Fix: Spray 100% silicon oil into the hop-up feeding tube. Fire a couple of rounds to spread oil.

Issue: Torn Bucking
Fix: Remove hop-up and look down hop-up chamber side to check for issues. Nothing should be sticking inside the barrel besides the nub from the top down. Remove inner barrel and bucking to replace.

Issue: Inner Barrel rotated and not centered
Fix: Remove barrel locking clip. Look down the chamber side of the unit and try to rotate the barrel by hand. The insertion of the bucking and nub should be centered.

Issue: Compression Issues
Fix: Requires the gearbox to be opened and the piston head, cylinder head, and air nozzle to be inspected. 

FPS is lower than usual. 

(List is categorized from Easy to Hard Troubleshoots)

Issue: Incorrect hop-up adjustment
Fix: Check the hop-up setting. Turn it down or off and re-tune the settings to ensure proper function.

Issue: Inner Barrel Dirty
Fix: Using a cleaning rod with a shop towel or cloth pad to swab the inner barrel for dust and debris.

Issue: Dry Bucking
Fix: Spray 100% silicon oil into the hop-up feeding tube. Fire a couple of rounds to spread oil.

Issue: Torn Bucking
Fix: Remove hop-up and look down hop-up chamber side to check for issues. Nothing should be sticking inside the barrel besides the nub from the top down. Remove inner barrel and bucking to replace.

Issue: Compression Issues
Fix: Requires the gearbox to be opened and the piston head, cylinder head, and air nozzle to be inspected.

Issue: Nozzle/Tappet Timing issue
Fix: Open gearbox and inspect tappet plate and sector delay chip/ sector gear tappet peg. Move by hand and the air nozzle should be moving forward as the sector gear is release the piston.