Gear can help your Tactics... and can change them as well, But the idea that gear IS tactical doesnt seam right to me....
Anyway, If your going to add something to your gun, you have a million options. You can do things to make it more "beautiful" Like engravings and nice wood work. You can do things to make it more comfortable or shootable, like different grips or softer recoil pads...
Then there are things you can add to your gun to help you in a "tactical"/ real life confrontation. Such as Flashlights, sometimes lasers, Different optics, and even custom gun work. It's up to you to decide how much custom work you want to do to your gun, and then you have to be smart about how much "gear" you add to your gun.
Every ounce is felt, and a heavy weapon can slow you down. Sometimes a Pistol with a flashlight mounted can be enough. Or even just a set of night sights.
But if you add on a (Heat shield, Forward vertical grip, laser, flashlight, optics, controls for all of them, even those magazine clips that hold two mags together, or extra shells on the stock of your shotgun.... All that stuff adds up, and for any real life, or HD situation... you'll find alot of gear not suitable for your tactics.
http://dictionary.reference.com/browse/tactical