The modern duty handgun is safe, dependable and durable. But for good measure, here are a dozen rule violations which can make a handgun less reliable:

1) Get bug repellent on a polymer gun

     The rumors are true. DEET (N,N-Diethyl-meta-toluamide) is one of the most effective bug repellents in the business. Unfortunately, it is also an extremely effective solvent. Some manufacturers have warnings about getting DEET (and other solvents) on the magazine feed lips. It's actually best to avoid overspraying DEET-based products on any part of the gun.

     When shooting in a mosquito-prone area, apply DEET-based products to the back of the hand, not the palm. This will also keep the palms from becoming slippery.

     Solvents designed for cleaning guns, like Hoppe's No. 9, are safe for polymer. Clean the working areas of a handgun normally and use mild soap and water for where the hand connects to prevent a slippery grip.

2) Use steel case cartridges

     There has been a lot of discussion about the detrimental effects of using steel cased cartridges for practice. One would think that steel cartridges would score or break the extractor. Generally, they won't, as the cartridges are usually made of mild steel.

     Another theory says untreated steel will rust. Although there certainly is a risk of corrosion, almost all steel cartridges have a protective lacquer. There really isn't any usable data about galvanic corrosion, but there may be some steel products out there where this may be an issue.

     Steel cartridges are not recommended for use on a regular basis, as steel lacks the inherent elasticity of brass. It may be soft enough to feed in a chamber, but it does not seal the chamber like brass does. The bottom line: Using steel cartridges occasionally will not harm the gun. Use it sparingly and clean the gun well afterward.

3) Repeatedly chamber the same round

     A cartridge is composed of a brass case, primer, powder and bullet. When loaded, the case mouth must pinch on the bullet hard enough so it does not move prior to firing. Repeatedly chambering the same cartridge can shorten the length of some cartridges, to the point where the firing pin may not get a decisive strike; and it can cause the bullet to work its way out of the cartridge, causing it to change the characteristics of the shot or (in extreme cases) get it lodged in the barrel.