Hello all
I think I saw once a pic of an XD with a longer barrel. Not a silencer or anything, but it looked like maybe 1/2-1" more barrel sticking out of the end.
Is that possible, for instance... If I have a 4", could I use a 5" barrel too at times simply by swapping it?
Not gonna work. In fact, you might experience a loss of accuracy if you did such a swap, as the barrel and slide may not match up properly. There may be some gunsmiths out there that are offering custom barrel with a protruding compensator package that would be designed to fit on a 4" slide, but you'd be looking at a hefty price tag.
One of the main misconceptions about accuracy in relation to the length of the barrel is that it is dependent on the barrel itself. Though there is a little truth to that, when you're looking at a difference in barrel length between 4" and 5", the primary reason for an increase in accuracy will be a longer sight radius, not a longer barrel. If you were able to find a 5" barrel designed to fit on an XD 4" slide, you might see a slight improvement in accuracy, but since such a modification wouldn't extend your sight radius, any gains in accuracy would be negligible.
As some others have already suggested, upgrade to an XD Tactical if you're looking for better accuracy, and remember, when it comes to improving accuracy, the shooter is 95% of the equation, unless the gun you're shooting is a piece of junk.