This is a new receiver that is a "take-off" from a factory rifle or URG. This one has the DD M4A1 logo, and is highly sought after.
The receiver has an outline of a round towards the front inside which reads 5.56, and a marking toward the rear which reads M4A1.
These receivers are not something we have often. They are take-offs from full DD M4A1 uppers or rifles, and in the past, the rails were very hard to find, so we would buy the complete rifle and strip in to use the RIS rails for our military clone-correct builds. Since roughly 2020, the supply of RIS rails has been good. Limited, but steady, and our need to strip complete uppers just did not make economic sense. But, from time to time, we get custom requests, or customers would like the upper removed and replaced by the more modest DD upper, so these uppers come available, but not often. We take care in removing the uppers, and aside from a little grease on the threads and oil in the upper from the BCG, this is a factory new upper receiver.
Note: We also have the Daniel Defense logo upper receivers. Both are identical in construction, just different labeling.