I carry the GP100 4" every time I go out. It's heavy but even in my cheapo holster, I do fine. Also, I weigh 140 lbs. That thing hides away pretty good even with the rubber Hogue grip...
The holster: Bianchi 19046 6D ATB Waistband Holster-Sz 13 rh
The holster: Bianchi 19046 6D ATB Waistband Holster-Sz 13 rh