How to Lube an AR-15:

I use two lubes, (1) Breakfree CLP and (2) Breakfree LP. LP is just like CLP except it does not contain the cleaning solvent found in CLP. It is therefore more viscous and "stays put" better. If you can't find it in gun stores, you can find it online.

1. LP generously on the locking lugs, cam pin, and piston rings.
2. LP lighter where the bolt carrier group rides in the receiver.
3. CLP lightly on the firing pin, and in the fire control parts in the lower.

When I first shoot my AR, oil comes out the exhaust ports. I haven't cleaned it in quite a while; it's only necessary to keep adding lube generously.

ARs can run dirty and wet; but they can't run dirty and dry.

If generous lubrication does not cure the problem, it's the gun.