Fixed: Extraction problem (brass not sized enough)

[Old Soldat]

Just installed new upper. Loaded a round into chamber by hand and released bolt letting it slam round into chamber. Had to use a small hammer on charging handle to extract round. Tried numerous rounds same problem. These were all reloads.
Bought some new rounds (Hornady Black and Hornady Match) and tried same loading procedure - NO PROBLEM. Reloads worked ok in old upper. Suggestions??