Can anyone tell me how chrome lined CHF barrels are made?  What I'd like to know is if the barrel is chrome lined before or after the CHF process.

A mandrel is inserted in the barrel and multiple hammers hit the exterior with great force repetitively.  Once complete, the barrel is sent out for plating.

 

CHF barrels are extremely tough.

 

But comparing to other methods of manufacture not the most accurate. But enough for most purposes.

I imagine if the plating was applied before hammering, it would be completely destroyed as the steel was bashed into the shape of rifling.