Thread:Golurk 88/@comment-34517845-20181129172200/@comment-30076690-20181130211011

ERA can sort of protect from APFSDS, but not as effectively as most forms of armor

spaced armor protects a little bit against everything, in particular HEAT rounds because they detonate early and thus the jet dissipates. They also mean that a round which is designed to punch through armor might blunt itself and be less effective at penetrating the next bit of armor, etc

https://en.wikipedia.org/wiki/Spaced_armour

Also, ERA only protects against HEAT once over an area, spaced armor tends to maintain its integrity somewhat better.