I don't believe that POF AR uses a chrome lined barrel which can cause some issues if not cleaned properly (which is obviously harder to do). But in general, it does sound like a chamber pressure issue, potentially the 5.5.6 vs .223 mentioned above.
It can also be a sticky or over-sized chamber.
Overall, POF's seem to get get the love or hate response. But in the end, it is a mix of Stag/Bushmaster/ Rock Creek manufactured parts which is not too shabby a combination. They also have pretty decent customer service and if called will most likely fully help you out.
If you want to be successful at anything, you'll need to develop a never quit attitude. Don't let life happen to you. Grab it by the throat and make life dance to your tune.
Ranger KW Driver