5) Lubricate your magazines
We already discussed lubricating magazines with DEET, which is a no-no. Most manufacturers have a version of limited lubrication in their instructions. Some even go as far as recommending that one does not lube the magazine at all.
When penetrating oils became popular in the mid 70's, several anecdotal stories about bullet failure due to contamination from oil surfaced. Incidentally, they mostly concerned revolvers. The military, our largest data gatherer, found that coating a magazine with oil can cause ammunition to fail and render guns unreliable. Currently, small arms users are urged not to coat a magazine with oil or lubricate them liberally. The idea is to prevent over-oiling. The latest school of thought is to wipe it on, then wipe it dry. Or better yet, use a Tuf-Cloth from Sentry Solutions.
6) Mix practice and duty magazines
Does anyone want to use their practice magazine in a firefight? Not really. Having a set of practice magazines will make for more realistic training. Officers should pull the floorplates off the practice mags and paint them a unique color. Orange (or pink, blue, etc.) for practice, black for duty.
Agencies who issue a single gun/single caliber can provide practice mags for tactical training. They should use carpet remnants behind barricades and likely areas of magazine changes to increase the likelihood that the practice mags will land on the carpet.
Officers should still shoot with their duty mags during static shooting drills. If their duty mags look like they will be marginal, they become practice mags. Remember, magazines are one of the most likely causes of failure and should be inspected before the watch.
7) Ignore your laser
If the officer is press checking the gun, is he press checking the laser? Red and green dots have been popping up all over the place in law enforcement duty because experts recognize their inherent advantage. Carry an extra set of batteries and press check the laser before and at least once during the shift. Carry cotton tip swabs to clean the lens of accumulated lint, dust and gases after practice.
8) Ignore the gun's exterior
Finishes on modern handguns have reached the point where they are fairly maintenance free, meaning users pay less attention to the outside of the gun, even though they may lubricate the inside meticulously. But even "stainless" metal can be stained. Ask any criminalist with a specialty in hemotaphonomy about blood stains and "stainless" surfaces.
A look under a magnifying glass will convince users that the exterior of his or her gun is dirtier than imagined. Buildup begins in the cocking serrations on the slide, where it is shoved and removed from a holster. Flecks wear from the holster and the surface of the gun gets shiny. If the user carries the gun inside the waistband off duty, the buildup in the grip and other recessed areas likely contains skin cells and antiperspirant. Dust from clothing and uniforms will congregate behind the hammer and trigger and where the slide and frame meet. This stuff will eventually work its way inside the gun.
Use a toothbrush and soapy water on the grip of the polymer gun, and a Tuf-Cloth on the whole exterior. Scrub the cocking serrations and sighting plane on the slide. Tuf-Cloth bonds a corrosion resistant shield to the surface and the cloth is reusable.
9) Fire on an empty chamber
Years ago, firing a gun on an empty chamber was considered a bad idea. Some firing pins were tempered to such an extreme hardness that they would crack without the cushion of the soft metal of the bullet primer. Although dry firing on most modern duty firearms will not spoil them, why tempt fate? An inexpensive investment is a package of A-Zoom Snap Caps, which can be reused just about forever.