This was done with pink acrylic yarn and a size H crochet hook. I didnt' have a pattern -- it was pretty much free-form. I crocheted it in rounds, mostly, except for where I needed to add flat panels to allow for the diameter changes for the trigger guard and the grip. I started with a chain of 6 in a circle, then did single crochet outward and finished with double crochet for the last three rounds, for a slight finish to the border.
The crocheting is a bit uneven on one side -- the flat panels done in rows where the bottom of the cozy had to drop down for the trigger guard and the grip were slightly askew. Also, a few of the corners in it are a bit uneven. Overall I think it came out pretty well and as I expected.
I am considering making a pompom from pastel pink and purple sparkly yarn and sewing it onto the barrel tip of the cozy.