I would like to add that maybe the Alaskan in a .480 might be just the ticket. I'm not sure, but perhaps the .454 in a 2.5 inch barrel would be more handcuffed (as far as velecity is concerned) than the .480 would be in that barrel length. I have a .480 (7.5 inch barrel), and I shoot 400 grainers at 1200 f/s. I love the caliber and gun, Ruger SRH.
To answer your question, I would never shoot a ported handgun without plugs. That's just me.
Good luck with your choice,