A little help with HK barrel markings

[mp5a3]

I have an MP5 registered reciever pushpin gun registered in 1986, the gun is also dated 1986 as is the bolt carrier. I was looking at the barrel and it appears to have a different date. Could it be this is a real MP5 barrel and not a cut down HK94 one ? Also what are the grooves in the barrel ? Any idea what steel was used ?




It's hard to make out, but it looks like there's an eagle and a few other marks..

 

[Maverick223]

The rings that you see are milling marks made from turning the barrel on a lathe and exhibit a typical (relatively low quality) finish for a part that cannot be seen with the forearm in place. The steel should be cold hammer forged ordinance steel (standard HK bbl steel), but I have no idea what the exact grade/hardness is, nor do I know anything about the markings.