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Firearms Training For Beginners


 One of the topics we teach during firearms training for beginners is understanding caliber and knock down factor. Of all of the gun-related debates, we argue which caliber is best for personal defense the most often. There are a few different reasons for this; the first is because personal protection is essential, the second is because people would like to know just one answer, and the third, there is no definitive proof that one works better than the other. 


The answer is simply that what caliber works for you may not be the proper caliber for me.

What is Caliber?

To understand and caliber and knock down factor, we must first look at definitions. The most basic definition for caliber refers to the diameter of a gun barrel’s inner opening (the bore) and the diameter of a bullet. Caliber is a measurement of the diameter of the bullet, not the casing. The caliber designation has nothing to do with the round’s power, it only defines how big of a hole it will make.

The name of ammunition is typically its caliber in either 100ths of an inch or in millimeters, and another designation; for example, the company that holds the original patent on the round.  

For instance, the name .45ACP (Automatic Colt Pistol) tells us that this round is forty-five one-hundreds of an inch in diameter, and that Colt originally patented this round.  Keep in mind, that the round carries the same name regardless of whether it’s shot in a Colt, a Kimber, a Springfield, or other manufacturers.

What is Knock Down Power?

Basically, without getting too scientific, it’s the energy produced or delivered to a target. It is a measurement of a round’s power, using either the kinetic energy formula or the Taylor Knock-Out Factor. TKOF was developed by big game hunter, John Taylor, as a way to compare the effectiveness of different big game hunting cartridges on large, thick-skinned, game. In the case of self-defense, it relates closely to the stopping power of a weapon. Stopping power is the ability of a firearm to incapacitate or immobilize a target.


What is the Best Caliber for Self Defense?

When comparing caliber for the best defensive option, our top recommendations inside our firearms training for beginners are: .380, 9mm in a semiautomatic, and a .38 special in a revolver. 

We recommend these particular calibers for self-defense, specifically because of the Taylor Knock Down Factor as mentioned above. 

Let’s refer to this graphic:


Our key takeaway is that we do not consider anything under TKDF of 3 a defensive caliber. The calibers we recommend fall within this range:

9mm = 7.14

.380 = 4.93

.38 Special = 5.30

Visit this blog post to view our list of this year’s recommended concealed carry weapons for women. (and new shooters)

Conversely, we wouldn’t recommend are .22 caliber and .25 caliber because they fall inside the red zone. In layman’s terms: it’s not large enough to stop a threat. A .22 caliber can kill if it hits a vital organ. Typically, however, it doesn’t have the penetrating power. Picture a large man, under the influence of meth or another hallucinogen; You could literally be shooting him repeatedly with a .22 caliber, and he will still be able to carry out his attack. The question would be then, why bother carrying anything at all? This is why we steer our students toward defensive calibers.

We recommend the largest caliber that you can accurately and consistently shoot and manage. The NRA defines Defensive Accuracy as being able to hit an 8-1/2″ x 11″ sheet of paper from VARIOUS DISTANCES 5yds, 7yds. 30yds (the qualifying distances for the State of Illinois Concealed Carry Live Fire Qualifications.) Vital organs are usually within those dimensions. The USCCA calls this the cardiovascular triangle. The stopping power is important, but the trade-off will be recoil, which deserves consideration. You should be able to shoot consistently at center mass in tight shot groupings.

A Word About Ammunition

We recommend that defensive ammunition, like hollow points, are designed to stay in the body and shock the cardiovascular and nervous systems.

First, this type of ammo is designed to stop the body of an attacker, rather than over penetrating and injuring or killing an innocent bystander. This risk was documented by the NYPD in 1998 when 46% of innocent bystanders that were struck by police bullets were hit by rounds that passed through an attacker’s body or another object. Not only were innocent bystanders affected, but what’s equally troubling is that 39% of police struck by “friendly fire” were hit by bullets that over penetrated an attacker’s body.

Second, violent encounters are typically fast and close. 78% of violent attacks that result in the use of firearms for self-defense happen between 9-15 feet. This means that the faster you can stop an attack, the higher the probability you will survive. Since hollow points shock the cardiovascular and nervous system more quickly than jacketed rounds, ultimately fewer rounds are fired, and an attack is resolved quicker. Additionally, the fewer rounds that are fired in a self-defense situation, the lower the liability the shooter faces.


What Caliber is Right For You?

In our PPG Firearms Training for Beginners, we want to equip our students for self-defense. The choice in caliber makes quite a difference. We also ask questions like; does the gun fit into your hand? Can you control the recoil and get accurate hits, and fast? Does the gun hold enough ammo to effectively solve a problem? 

We work with our students to first understand caliber and knock down factor, then find a combination that will deliver a balance of power, speed, and capacity. In the end, all that matters is that you can shoot, and shoot effectively. 

Are you interested in firearms training for beginners? Contact us at Pew Pew Guru and let us help you get started! 

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