Just finished my build and no ammo through it as of yet. When I pull back on the charging handle (BCM Gunfighter), it clicks at the full retraction point and is then loose, i.e., no spring tension to bring it back forward. The BCG stays back and will not go forward until the bolt catch is depressed, and then the BCG goes forward. With the Ejection Port Cover open, the bolt is exposed about 1/4". There is an empty mag installed (PMAG Gen 3 5.56). As far as parts go, I have installed the following in my build: Magpul CTR buttstock, Spikes S2-T2 buffer, POF anti-tilt buffer tube, and a Tubb Flat Wire AR-15 Buffer Spring. The reason for the non-Milspec items is that the gas system is an Osprey Gas Piston system (mid-length). In regards to the trigger group, I purchased the DPMS LPK and upgraded that trigger by using the JP Enterprises Trigger Spring (yellow), the AR15 Trigger Adjuster, and the KNS Hammer and Trigger Pins Non-Rotate upgrade. The only other thing I changed out on the lower was a Norgon Ambi-Mag release and the Ultimate Arms Gear Ambi Safety. In regards to lubing and/or oiling the different parts, I went by the YouTube video that MidwayUSA put together on both the upper and the lower. Thanks for any help.