User blog comment:IamJakuhoRaikoben/Chapter 473: Red Lightning, Review./@comment-5303512-20160216234812

I wasn't sure what the Railgun in the "Railgun Bombardment" was, I heard the word before in a few movies and games but wasn't sure it was a real thing, but after getting a definition for it makes perfect sense now, it is a weapon that fires off electromagnetic projectiles which can achieve a high powered kinetic force.

Now it makes more sense as to why Laxus was uneffected by it.