Chemical deterrents may be legal to carry when you have no other legal personal-protection concealed-carry option, or for use during those very rare and tender moments during violent confrontations when something less lethal than a firearm may be appropriate. Chemical spray-liquids and spray-gels are not ideal for all occasions. Some aggressors are so drugged-up, drunked-up, or so darn tough that chemical goop won’t affect them. Spraying chemicals at a gunman would probably be your last great earthly act of defiance. Some may argue that, if you are sure that you are doomed no matter what you do, spraying may just provide you the slimmest of chances for a miracle. Others would argue that, for a life-and-death encounter, any gun is better than the very best chemical deterrent; having a mouse gun is better than having no gun. That aside, if you cannot legally carry a gun, having chemical spray may be better than having nothing at all, perhaps giving you some chance when otherwise you would have no chance. You pray, you spray.
For an interesting exchange of ideas and insights on chemical deterrents, visit this thread at Say Uncle.
James at Hell in a Hand Basket talks about chemical deterrents here. He is a personal defense instructor and much more qualified on the subject than I am.
So, what does the honest citizen carry for personal protection in Illinois? The laws here pretty much limit us to carrying prayer books. While prohibited from carrying guns, clubs, knives, stun guns, sticks and stones for protection we are “allowed” chemical sprays and gels. I’ve carried different brands of teargas or pepper spray for over twenty years; I never had an occasion to use any of it so I do not know how effective it is as a deterrent. Remember that any act of self-defense on your part is easily viewed as an act of aggression by the authorities, even when you just use bluster, bluff, and naughty words. As soon as possible, retreat to safety, be the first to call 911 to report an incident, and always have your lawyer on speed dial.
When off my property, my preferred everyday carry consists of two Kimber Pepper Blasters (one clipped in my shirt pocket and one in a nylon belt holster) and one 2 oz. Mace combination OC / CS spray (clipped in my other shirt pocket, or clipped to my shirt collar; the Mace belt-clip does not work well on my belt). I sometimes will carry only one Kimber and one Mace but I firmly believe more is better.
Kimber Pepper Blaster uses a non-aerosol pyrotechnic delivery system and will not lose pressure over time as some conventional sprays do. The ingredient formulation combines a solution of 10% OC (2.4% capsaicinoid content) with Benzyl alcohol for increased viscosity; it is bit more of a gel than a liquid. The OC comes out at speed around 90 MPH with a range of 13 feet. The units are not refillable; once you fire both loads, you toss the unit and buy a new one.
As with the double action High Standard .22 caliber Derringer, you get only two chances with the Kimber Pepper Blaster so you may want to consider carrying some backup; you may miss with the first shots or you may be facing multiple aggressors. Your target area when using chemical spray-liquid or gelled glop is much smaller than when using a bullet; with chemicals your target area is the face of the bad-guy. Any kid who has ever been in a squirt-gun fight with his brothers can tell you that hitting that target area is much harder than one would imagine. Spraying the bad-guy in the chest or the crotch would probably do nothing to stop aggression whereas shooting him anywhere with the smallest caliber bullet has a good chance to at least get his attention. With chemicals, you have to score a hit to the bad-guy's mug. Don’t expect an aggressor to cower from your threat to spray him. Once the bad-guy knows he is facing a chemical spray he may continue his attack and be a more difficult target, ducking-and-covering to protect his face. Derringer tactics traditionally have relied on surprise and may be the best bet when using chemicals. “When you have to shoot, shoot, don’t talk.”
Getting a good firing grip on the Kimber Pepper Blaster (aka Kimber Guardian Angel) is not easy. What works best for me is to use the middle finger for the trigger while keeping my index finger alongside the top. If you have long fingers, make sure none of them extend past the muzzles of the unit when firing.