Man, I love this pistol! Went to the range today with a buddy. He was shooting his new Shield. Nice piece. Very accuate. But my XDs45 3.3...my oh my. It is sweet. Don't know why you would want this gun in the 4.0 version. Seems to mess with the whole original concept. Accuracy maybe? Even with my old eyes I was hitting milk jugs at 50yds! 3ot of 5 times. I can't see a 4in barrel being any more accurate than that. Would like to have just the 4" barrel itself, threaded, to run in my 3.3 slide, with a nice can hanging from it. That would be a hoot. Sorry that no one else's came back from recall with the sweet trigger that mine did. I see a lot of complainers online. Mine is beautful. No coplaints about this firearm at all. Thank you Springfield, you got this one right.