Is an Airgun Good for Self Defense? Another one of those questions I get asked fairly often that's a bit hard to answer in a few sentences... Not all of us have easy access to a 9mm pistol or even a rifle but many of us can get our hands on an airgun fairly easily and they look real enough, I guess that is one thing they have going for them.
But what if the mere sight of what looks like a gun does not scare an intruder off? If you where hoping that would be enough, you may just be out of luck and what if you just brought an Airgun to a "real" gun fight? You are going to be drastically "outgunned" pun intended and here's why. A 4.5mm Steel BB weighs about 5.1 grains and generally you are looking at about 2-3 foot pounds of energy from a CO2 BB gun. Even a .177 caliber lead pellet is only marginally heavier at around 7-8 grains and if you're really lucky you might just get 4 foot pounds of energy out of a CO2 pellet pistol.
So let's take a look at a fairly conservative "real pistol" rounds, the 9mm. The 9mm rounds come in different bullet weighs but you can get a 120 grain 9mm in a plus p ammo with as much as 400 foot pounds of energy and even with that much raw power, many people claim that a 9mm round does not always have enough stopping power to put down a person even when shot multiple times center mass. It just depends what vital organs or arteries you hit that determines if he gets lucky or you get lucky.
Your 5.1 grain 4.5mm Steel BB is not going to do anything if it hits any type of clothing and even if you find some flesh it's just going to piss off the intruder.
My suggestion is to consider a bat or a golf club or a really big knife or just about anything other than an airgun because if the sight of the airgun replica does not scare an intrude away then you are really buggered.
Keep in mind that you need to abide by any laws regarding the use of self defense in your areas. Even just physical force could be considered a crime and at the end of the day you are ultimately accountable for your actions.