Zero Like A Hero Pt 1: What it Means

If you're going to hit your target, you need to use your sights. For those sights to be effective, you need to make sure they are aligned with the gun. This aligning process is called zeroing, and is critical to accuracy. (Note, everything in this process assumes that you're using a scope or other optic, and that it is properly mounted. How to diagnose and correct mounting issues will be covered next week.)

What Zeroing Is
The first thing to understand when you zero your optic is what your bullet is doing when it leaves the barrel. Contrary to what some folks think, the path a bullet takes is anything but straight. Gravity and air friction obviously make a bullet slow down and fall to earth, but far more interesting is what happens as a bullet leaves the muzzle.

1. The point where the focal point of the optic and the trajectory of the bullet intersect is called zero.
2. Because your optic is higher than the bore of your rifle, you have to focus it lower than parallel. This means that your optic's line of sight is essentially pointing down when the barrel is held parallel to the ground.
3. When you aim at a target far away, your optic's line of sight is parallel to the ground, which means that the bore if your rifle is now pointing up. 
4. Therefore when you fire your rifle, the bullet seems to climb for a bit,  although in actuality it's following a parabolic arc. It rises for a bit until wind resistance slows it, and then it drops. 
5. If your rifle is zeroed properly, the bullet will drop and hit where you're aiming. 

So from the shooter's perspective, the bullet exits the barrel, climbs some, then slows down and drops until it hits the ground. In this process, the projectile passes through the crosshairs of your optic twice, once on the way up and once on the way down. This is important, because it gives the opportunity for a very simple zero method: you can zero your optic at a close target (called near zero), where it's easy to see where you're hitting, and that will also give you a zero at a larger distance (called far zero). While I suppose you could just set up and bang away at that range straight away, if you're not already close to zero you might not even hit the paper of your target.

This is where we revisit the up and down path of a bullet, and the simpler zero method I mentioned earlier.

Example: 55 grain .223, one of the most common cartridges in the USA. 

http://aussiehunter.org/wp-content/uploads/2011/12/040-223-Rem-Trajectory1.jpg

A rifle's zero is set at a specific range determined by the shooter and based on a number of factors. The factors that shape this decision include the caliber of the rifle, the intended uses of the gun, and the shooter's skill level. As an example, my .22LR is zeroed at 50 yards. Most of my hunting rifles are zeroed at 200 yards, and both my precision rifle and my wife's are zeroed at 400. Erin zeroed her Mosin at 300 yards, because she was feeling froggy.

• A good rule of thumb for 5.56/.223 cartridges is that the rifle will do the same thing at 50 yards that it does at 200. This means that if a rifle is dead-on at 50 yards, it should also be dead on (or very close) at 200 yards. 
• 7.62mm/30 caliber cartridges are a bit different due to bullet weight and powder charge. Erin zeroed her 7.62x54r Mosin 2" high at 25 yards, so it should hit roughly 2" high at 200 yards as well, and dead-on at 300. 
• 7.62x39, used by SKSes and AK-47, has a dramatic arcing trajectory and does well with a 25/200 yard zero.
• .22 Long Rifle is obviously not as aerodynamic nor as fast as a centerfire rifle, so it has a much shorter range and zero. Ideally, a .22LR should zero at 60 yards, but 60 yard ranges are awful hard to come by. This is why mine zero at 50 yards, and the difference ends up being negligible. 25 yards remains a good starting point for getting on paper, then making the needed adjustments at 50 yards.

Once you've set your 25 yard zero, move your target out to your desired range and confirm that your rounds are landing where you want them to. You'll very likely have to make some small adjustments, but you should be fairly close to your desired outcome.

A Note on Maximum Point Blank Range
Maximum point blank range is the longest range at which a given cartridge stays with a predetermined circle. In general use, the radius of that circle is the highest point above the muzzle that the bullet reaches. Once it has dropped that same amount, it has reached maximum point blank range. For most .30 rifles, this range happens to be somewhere in the neighborhood of 200 yards.

What does all of that mean? In short, I can hold the crosshairs of my hunting rifles at the desired point of impact at any point between 0 and 200 yards, and hit close enough to that point to have high odds of a clean, lethal shot. It makes quick shots on game animals simple and instinctive. The same logic applies to the .22LR with a 50 yard zero (and actually is the math behind declaring 60 yards to be ideal).

Get zeroed and get practicing.

Lokidude

Gun Blog Variety Podcast #68

Adam and Sean bring you Episode 68 of The GunBlog VarietyCast!

• Erin Pallette tells us about Zones of Assessment.
• Nicki Kenyon answers that burning question about Iraq, about Russia, and about Foreign Policy in general: "Was Romney Right?"
• Weer'd takes his shot at that WRAL attack on NFA Trusts in one of his patented Weer'd Audio Fisks. 
• And make sure to listen for a peek behind the curtain and we'll tell you how the podcast gets made.

Thanks for downloading, listening, and subscribing. Please like and share The GunBlog VarietyCast on Facebook, and if you use iTunes, give us a review!

Listen to the podcast here.

Read the show notes here.

A special thanks both to Firearms Policy Coalition for their support and to our sponsor,Law of Self Defense. Use discount code "Variety" at checkout and get 10% off.

Stop Sabotaging Your Situational Awareness

Not actually Erin.

Picture by KJ Photography

& is used with permission.

I and others on this blog have talked a lot about the importance of Situational Awareness. This is because situational awareness is the key to being prepared; if you are surprised, it won't matter what your preparations are, as you will be unable to utilize them as your brain grapples with what is happening.* In many ways, situational awareness is preparedness, because if you can't react in time then all your preparations are for naught. It is a constant source of astonishment for me, then, when I notice just how often so many people willingly place themselves in danger while disabling their situational awareness.

Now let me be clear: there is a time and a place for tuning out all distractions, be it to get work done or to relax. After all, everyone needs to sleep sometime! This is what Col. Cooper calls Condition White, and it is best done in the safety of your own home. Barring that, do it in a place that you know (not think, not suspect, but KNOW) is safe, preferably among people you trust to have your back.

But just as it's possible to get drunk responsibly, it's also possible to become distracted irresponsibly. And worst of all, many people choose to be irresponsibly distracted. Perhaps they feel safe all the time; perhaps they think that society exists to protect them; perhaps they don't think at all.

However, if you are reading this blog then you have made a conscious decision to be responsible for your own safety. Here, then, are the things you will need to stop doing in order to give your situational awareness a chance to work for you.

Don't Lose Yourself in the Visual
There's an excellent scene from The Matrix which perfectly illustrates this point:

Were you listening to me, Neo? Or were you looking at the woman in the red dress?

Human beings are visual creatures. This can be an incredible advantage, as we are biologically primed to notice movement, facial expressions, body language, and patterns or behavior which seem out of place. Soldiers, police officers, and medical personnel are highly trained to notice important visual cues.

However, this biological optimization can also be a weakness. We are easily distracted by movement and color -- just try to have a conversation with someone when there is a television within your field of view. Your eyes will be drawn it, because you have millions of years of genetics telling you "Look at this flickering thing, it is important to your survival."

If you are reading in a book, watching a movie or television, or engrossed with your computer or smartphone, you are in condition white. Don't do this in places where you ought to be in condition yellow, or you are sabotaging yourself.

Don't Keep Yourself from Hearing
Sound is another immersive sensation for humanity, and is equally beneficial and distracting. While it is marginally safer to be out in the world with headphones than it is to have your eyes glued to a screen, there are still important audial cues that you can miss if nothing can penetrate your wall of sound.

Listening to music or a book is fine; just make sure that it isn't so loud that you cannot hear important things, like trucks backing up or someone shouting "Hey, look out!"

Don't Daydream (except at home)
Of course, you don't need a screen or headphones to miss out one cues; some folks are so good at concentrating (or daydreaming, which is concentrating without the focus) that they can miss cues necessary to their survival, such as the smell of smoke or a fire alarm going off.

It's okay to daydream, but don't zone out (or sleep) in public unless you have someone you trust watching over you.

Have Things Ready Before You Need Them
The classic example of this are your car keys: take them out of your pocket or purse before you step foot into the parking lot, because if you get to your car and then spend time digging for them, your focus narrows to "must get keys" and you lose the world around you. This makes you a very temping target, as all someone needs to do is get the drop on you and not only can they rob you, they can take your car as well. If you're a woman, this robbery-turned-carjacking could easily escalate into kidnapping and thence to rape if you are pushed into the passenger seat.

If you know you are going to need something, like keys or a flashlight or a knife, get it out and have it handy so that your attention can be used on deploying it effectively rather than getting at it.

Keep Your Head on a Swivel
That's a military phrase; translated to civilian it means "Don't just just straight ahead. Look to the sides and behind you as well." Be aware of your environment in all directions; danger can come from any angle.

Get in the habit of scanning from left to right as you go about your business. Occasionally look over your shoulder ("Checking your six" in military parlance) to make sure no one is following you; this can be done by moving your eyes to the side in the same direction that your head is sweeping and using your peripheral vision to check behind you. If something seems off, then turn your head (or whole body) and take a better look.


Do these five simple things and your situational awareness, and your ability to respond to surprises, will increase dramatically.


* It's a semantic quibble, but I differentiate between "Being startled or taken off-guard" and "Being surprised."  To me, the difference is that with the former, your opponent has the drop on you and goes first before you can react; in the latter, you are figuratively caught with your pants down and your brain requires several precious seconds to process what is going on -- seconds which put you at the mercy of your aggressor.

Thermo-Electric Generators

One of the regulars on our Facebook page posted a short video from the BBC showing a way to charge your cell phone or other small electronic device from a home-made device added to a clay firebox or stove. There was some interest in how this device worked, so I took a closer look at the video to try to figure out which method they were using.

For those who can't or haven't seen the video:

• The generator is two metal plates, about 4 inches square, bolted together, with three pieces of rebar welded to one of the plates (the fire side) and a square metal box (about 2x2x6 inches) filled with water welded to the other plate.
• The generator is inserted into a hole in the side of a fired clay cook stove that is burning wood.
• The captions on the video mention that the fire creates a heat differential in the metal rods sticking into the fire to “create” electricity. This is incorrect. The metal rods are there to provide more surface area in the flames.
• There is a pair of twisted wires coming from the middle of the metal plates, indicating that some part of it came from a factory.
• There is a white substance between the two plates, probably conductive paste as is used on computer heat-sinks.
• The wires are run directly to a cell phone and an LED flashlight, which means it is putting out around 5 volts of DC power.
• Since there are commercial versions of this on sale in America (Powerpot and similar), this was something designed for use by people with little to no money.

All of these points lead me to believe that they are using a Seebeck junction (sometimes called a Peltier junction) placed between two locally-fabricated pieces of steel.

Thermo-Electric Junctions
A Seebeck junction is a sandwich of dissimilar materials that will generate electricity when placed between a hot surface and a relatively cold surface. As the heat moves from the hot area to the cold area, electrons are knocked off of the material, creating an electrical flow. If you reverse the conditions and push electricity into the junction, one side will get hot and the other side will get cold.

Solid-state coolers are normally called Peltier junctions, while the thermoelectric generators are called Seebeck junctions even through they are the same thing.

Seebeck thermoelectric generators are not terribly effective -- about 5% efficiency -- but they are perfect for use in waste heat reclamation when placed in the exhaust or combustion chamber of wood-fired heaters.

Seebeck generators are fairly easy and cheap to buy. Since the main uses involve the Peltier (cooling) function, it can be hard to get (and understand) good data on the amount of energy you'd be able to get out of a given module, but I'll give it a try.

In Practice

Amazon has a cheap one if you want to try making electricity from fire. A bit over 1.5 inches square, it weighs less than an ounce and costs less than $10.00,  making it perfect for experimenting.

• Power output will vary with the difference in temperature between the two sides. The higher the difference in temperature (not the higher of actual temperatures), the higher the voltage and amperage that will be produced. This one has a maximum temperature of 150° C (302° F), so it would work with small wood fires or placed on the surface of a metal wood stove. 
• The cold side on the generator shown in the BBC video used a container of water to keep the temperature at 100° C (212° F). The hot side was the metal rods inserted into the flames, which in a wood fire is about 150° C (302° F). The difference is 150-100= 50° C. This is a small difference when looking at Seebeck generators. 
• Unfortunately, the seller doesn't give enough information to be able to estimate the power output. One of the buyers, however, mentioned getting around 7 volts DC by placing the hot side on a stove and the cold side on a ice pack.

A more expensive version can be found here.

• These modules can handle up to 350° C (662° F). 
• Wiring a few of these modules together to get the voltage you desire (around 5V for cell phones) would be the best route.
• Looking at the charts for a module the same size as the one from Amazon, a 50 degree differential would put out about 2.5V at a little more than 0.5A. Not bad for something the size of a pack of matches. 
• Wire two of them in series (connect positive of one to the negative of the other and draw power from the unused connections) and you'd have 5.0V at 0.5A. 
• To put those numbers in perspective, most older cell phone chargers (and USB 2.0 ports) are rated at 5V and 0.5A while the newer chargers are still 5V but 2.0A.

If you don't want to buy a module, you can find them in the common 12V coolers sold at Walmart, and most truck stops, and in high-end desktop computers (active cooling for the CPU-mounted between the chip and the cooling fins). Salvaging one and using it to make a generator would require a bit of knowledge of electricity and a way to determine which wire is positive and which is negative. Voltage output will vary according to the temperature difference between the hot and cold sides, so a cheap voltmeter would come in handy.

Thermo-electric junctions are interesting ways to generate small amounts of power from fire, something you'll probably already need in an emergency. Since there are no moving parts, maintenance is minimal and they're pretty fool-proof once assembled. I hope I was able to answer a few questions, but if you have more I will do my best to answer them. Feel free to leave comments here or on the Facebook page.

Prudent Prepping: EDC, Part the Latest

The dust has settled and the First 72 Hours have passed. Now we concentrate  on what to do in, and how to plan for, the long term via Prudent Prepping.

I've talked about not wanting to carry large amounts of stuff on my belt, and tried to go small, but that attempt ended up being slightly too small. Most recently I went medium-size, purchasing of a 5.11 sling bag to carry my daily supplies in an organized manner without going to a backpack. Two days after receiving the 5.11 bag, a good friend dropped off a lightly used Maxpedition Jumbo he found to be too small (!) for his needs. With this wealth of options you'd think I would be doing a happy dance with all of my choices... but I got some news from work that changes what I have to carry and use every day.

Top: Maxpedition, 5.11

Bottom: Handheld ordering device

Behold the new ordering device I an using, shown with its required holster, beside a pair of gloves for a size reference. I can't really keep the device in my bag and bring it out when I need it, since I'm using it regularly during my day. The carrying case has some advantages, though: my utility knife, magic marker and pen fit into the side pockets, eliminating the small clip-on pouch I was using before.

Since I'm a southpaw, the new ordering machine rides on my left hip now. which is where my sling bag normally goes. So now I'm back to carrying a little over one pound on my belt, along with having a bag carrying my miniature office supplies: note books, work sheets, small first aid kit, mints, hand sanitizer and other required junk.

This doesn't make me very happy, but I am happy to have a job.

A closer look at the 

handheld ordering device, about 1.5 times 

larger than the iPhone 5.

Purchases This Week

While going through Sam's Club I stocked up on a 90 count box of Emergen-C. Cold and flu season is here and half of the people I see every day are sneezing, hacking and coughing. This means if I don't try and protect myself, no one else is going to do it. This is an easy way to get my vitamins by mixing one packet into a bottle of water and drinking it at lunch.

The Takeaway

• I am carrying a smaller bag than a backpack, but still have stuff on my belt.
• Work dictates how things run during business hours.
• When I'm off work I can use my bag, but that means I have to load and unload my belt holster. 
• Personal protection means taking care of the internal needs (like eating) as well as external, so demands of the job come first. 

Recap

• 90 count box of Emergen-C. $19.98 from Sam's Club, $17.77 plus shipping from Amazon

Just a reminder: if you plan on buying anything through Amazon this Holiday season, please consider using our referral link. When you do, a portion of the sale comes back here to help keep this site running!

If you have comments, suggestions or corrections, please post them so we all can learn. And remember, Some Is Always Better Than None!

NOTE: All items tested were purchased by me. No products have been loaned in exchange for a favorable review. Any items sent to me for T&E will be listed as such. Suck it Feds.

It's Not Really a Knife Sharpener, But You Want One Anyway

There are a great many "miracle" knife sharpeners advertised, and unlike most miracle products, these actually work... mostly. By that I mean they will actually restore an edge to a blade, although they have some weaknesses. Instead of sharpeners, these tools would be better termed as "dressers."

Sharpeners vs Dressers

• Anything that advertises a sharp edge in 5-10 strokes is a dresser. They put an edge on ("dressing" the blade, also known as honing), but lack the ability to re-shape a damaged blade or remove serious nicks and chips from an edge.
• Whetstones and other proper sharpeners have the capability to make these kinds of repairs, and do them well. However, they are bulky, cost more money, and are slower and harder to use. In addition, most sharpening tasks don't need the full capability that sharpeners provide.

Most folks think that knives dull like this, with the edge actually becoming blunt:

Simulated cross-section of a knife edge

While this does happen in some cases, it's uncommon and is usually the result of rough work or abuse. Damage like this typically requires an actual sharpener to repair.

This is how most blades actually dull:

Not a crotch. This is another cross-section. 

Repeated work creates a curl of steel at the edge, which blunts the cutting ability. This where dressers shine. They quickly "dress" the blade, removing the curl and restoring cutting ability, in a few quick strokes.

There are quite a few common knife dressers, and they all work at roughly the same level.  My two favorites are the Smith's Pocket Pal and the Speedy Sharp.

The Speedy Sharp is a carbide cutter bonded to a handle. Its shape and size mean that it can be used to dress almost any blade, from a small pocketknife to a machete or axe. Using the Speedy Sharp requires a bit more attention, because holding it at a consistent angle to the blade gives the best edge, and it is a free-hand tool. (Editor's Note: I feel this is actually a sharpener, as I have used the carbide cutter to literally carve an edge where none existed. The trick with using it, as Loki says, is attention to angle and pressure. An understanding of the difference between Positive and Negative Rake is also important. For more information, see my review of it here.)



The Pocket Pal has two grooves, one with coarse carbide edges, and one with a finer ceramic surface. It is very user friendly, with paired edges guiding the blade to a consistent stroke. It also has a diamond rod for sharpening serrated blades and other odd cutting implements.


Both of these tools are about the size of a small pocketknife, and weigh mere ounces. They're quite durable, and will readily extend the life of a blade between uses of a larger, more complex sharpener. They're also inexpensive enough to be good stocking stuffers, or simply to stick in all your bug out, EDC, car and other bags.

Sharp knives are safer, and get the job done faster. Knife dressers make keeping your edge quick and easy.

Lokidude

Cyber Monday Prepping Deals from Erin's Favorite Companies

Not actually Erin.

Picture by KJ Photography

& is used with permission.

There are three great deals that I want you folks to know about before they disappear.


I've sung the praises of the Solo Stove before (as recently as last Wednesday), and getting a free pot & free shipping is a great deal that doesn't happen very often; it might pop up again right before Christmas, but then again it might not. Best of all, this works with ALL their stoves and pots: the smallest pot sells for $35, the middle sized one for $46, and the largest (actually a 2 pot set) for $60; and you get those free when you buy the matching stove.

Another company that I really like, Power Practical, is offering 50% off its most popular items (that's most of them and includes the nifty Power Pot) and free shipping for all orders of $50 or more.

UVPaqLite also makes awesome products. (I had the chance to meet the owner/inventor at the NRA Convention in Nashville this year, and she's a really awesome lady who listens to her customers and has tons of great ideas), and they are running a holiday special from now until Dec. 15 and you can get some great values. My favorite is the Scout Pack: designed for the Boy Scouts, but of lots of use to anyone who hikes, backpacks or camps. (I have one of these and I love it.)

Or get the 5-pack of reusable mini glow sticks and either hand them out as stocking stuffers or use them as zipper pulls for things you'll want to be able to quickly find in the dark, such as the opening to a first-aid kit.

Or just use the coupon code SAVE2015 to get 20% off of everything else in the store.