I have a DPMS LR-308 with 24 inch fluted barrel, factory. Scattered elsewhere in this forum is a complete description and a photo.
I had some jam problems early-on. It was not a serious problem for me because I was mostly firing single-shot by tossing one round at a time into the open port- on top of the magazine- and releasing the BCG to load.
After the first time at the range I washed all metal parts in powder solvent first and then in my own "gun oil." I mix 25% to 35% Kroil into Mobil One 10W-30 Full Synthetic. (Harbor Freight has a nice little 4 oz oil can.) This provides relatively permanent lubrication and moisture proofing: the Kroil is a cleaner. I pour/inject this oil into all openings, crevices, crannies and let it sit as long as possible. I fill the bore and then drain the fluid back into the oil can. Then I spend some time drying with paper towel. After that initial treatment, just wipe lightly with paper towel barely damp with the oil. (At the range, run a dry patch or maybe two through the bore first thing, then shoot 2 to 5 throw-away rounds. During a range session I use powder solvent to clean the bore. My own oil is used later for long-term protection and when the Kroil has time to do what it does.)
After a few dozen rounds of various kinds of ammo, factory and handloads, several trips to the range, the rifle seems to run properly. Ejection is relatively light and consistent. My 'range box' is a cheap Stanley toolbox from Wal-Mart that measures 9x9x18 inches. I take the tray out and leave the lid open with the box close alongside my rifle on the shooting bench and it easily catches all fired brass.
The lightest bullets I shoot are 140 grain Russian ammo. I discard those lacquered steel casings. The others run from 150 to 190 grain with most in the 160+ to 180 grain range. I reload my fired factory brass- as many times as I feel comfortable with any given cartridge case.
If I do not catch the fired cases, they all land within a couple of feet alongside.
From reading within this forum, maybe my factory rifle has a relatively heavy BCG? Perhaps your BCG is light and replacing parts necessary to make it heavier would help? I/we need other comments about BCG weight. Maybe all you need is a stronger buffer spring behind your BCG? My own experience working on machinery says to find the easiest and least expensive fix.
From your posts, it sounds like a new factory rifle. DPMS might fix everything for you with no fuss or muss? That would seem to be the first thing to try?
