Kendall.
Wrap the (unloaded of course) pistol in wax-paper or a thicker zip-loc bag (freezer storage bag thickness, not sandwich baggie) and insert it into the holster and leave it sit overnight. The bag or wax paper will bunch up around the ejection port and trigger-guard and relieve some of the tight tolerence in these areas. This method usually works without the need for any sprays or leather conditioners. I occassionally have to do this on some of the holsters leaving the shop when I final test-fit them with real firearms, due to the dimensions being slightly smaller on some of the mold guns. Some say the wax-paper is preferable if you wrap it with the waxy side out as it also leaves some wax residue inside the holster to slicken things up, but I've found th plastic bag to work effectively, and recommend to customers using the bag I shipped the holster in if they find it tight. Josh Bulman, Mitch Rosen, and Galco also sell a leather treatment for slickening up the inside of a holster that will not soften or stretch the leather.
_________________
http://www.garritysgunleather.com
"He who works with his hands is a labourer, he who works with his hands and his head is a craftsman, he who works with his hands, his head, and his heart is an artist."
(St Francis of Assisi)