I was flying a B24J this morning, and shortly after take off, I noticed an enemy TBM-3 rolling in. We dueled it out for a while and I noticed that I was seeing a lot of flashes and it even looked like he exploded at 1K range and still he survived. The only ammo I had left was in the waist guns and he flew right along side of me and I was hitting him point blank with my right gun and the bullets were like rubber bullets.............no effect what so ever!! 
Why did this happen?  I experience this a lot especially when attacking bombers. I get within 400 yards and I see my bullets hitting there plane to no effect. I take two rounds and I'm dead.....Why are my bullets rubber??
Also, 
Thanks..................Mag00