Deal With It
First and foremost, deal with it. Each department selects and issues equipment for its own reasons, not yours. There are some agencies where officers may purchase and select their own weapons, but this is not the case for the officer who contacted me. Sometimes you are issued equipment that you don't like—sorry. I asked the officer if he was aware of the issue duty gun prior to taking the job. "Yes," he said, "But…" There are no buts here. Deal with it and adapt.
Train to Live, Not to Whine
If you are uncomfortable with the weapons system (weapon, ammo, and holster) that you are issued, then train harder and train smarter. Accuracy is what does the job. I don't care if you have a fire breathing, maxed out, loaded magnum plus. You have got to put the projectile in a location of the body that will successfully stop the aggressive action. 'Nuff said.
Comfort level with the handgun not there yet? Then learn as much as you can about it. Research all you can about the weapon, care, maintenance, and how to maximize your working knowledge of it. You cannot avoid this instrument just because you don't like it. You must master your weapon, and then your confidence will improve.