B-17 chin and tail .50 cal barrell extensions

[DarrellC]

I've seen these extensions on some .50 cal's. What are they?

 

[T Bolt]

I could be wrong but I believe they are flash shields so as not to blind the gunner.

 

[Greyman]

I forget what they were called - blast tubes I think - for the chin guns. I read that when fired at maximum elevation the guns could crack the nose dome, so they added the extra bits to guard against this.

I'm not sure about the tail guns though.

 

[Greyman]

Found out what the tail stinger 'extensions' were ...

The Fortress tail guns were mounted on a central pillar and firing the guns created throw-off in the direction of the gun being fired. Special blast tubes that were cut diagonally produced a counter-movement in the correct direction.