considering building an integral... Ported?

[este]

So I'm considering doing an integral semi. I know from working with other integrals (mp5-sd) that porting releives pressure and slows the bullet.

Is that the only reason? Would there be any reason at all to do that on a whisper where the loads will be specific to the gun anyhow? Seems wasteful to slow a bullet that could have just been loaded as a subsonic

or am I missing something?