Wednesday, December 7, 2022

Prepper's Armory: Using Iron Sights

Continuing from my previous post, the quality of any sighting system is of little benefit if it isn't applied correctly. The two elements of using iron sights properly are referred to as Sight Alignment and Sight Picture.

Sight Alignment
When your front and rear sight elements are in proper orientation to one another, you have Sight Alignment. With proper sight alignment, aiming is easier, but if sight alignment is not correct and not consistent, then everything is harder.

When using Patridge sights, the top of the front sight blade (or post) should be level with the top of rear sight block, and it should be centered in the rear sight notch. If the front sight protrudes above the rear sight, your bullets will hit higher than you intended; if there is a gap between the top of the front sight and the top of the rear sight, your bullets will hit lower. Similarly, if the front sight is held to one side or the other in the rear sight notch, hits will be to one side or the other on the target. It's also very difficult to hold the sights out of alignment consistently, meaning that your point of impact will wander. 

Tang-mounted or Receiver sights should have the top of the front sight blade (or middle of the crosshairs) centered in the field of view. Tang sights have different sized apertures for different ranges and light conditions.

Image courtesy of the TN Handgun Carry Course

Sight Picture
Looking through properly aligned sights at a target involves dealing with three elements at different distances. Unfortunately, we have a problem in that our eyes can only focus on one element at a time. 
  • If we focus on the target, the rear sight is practically useless
  • If we focus on the rear sight, the target is effectively a blob.
  • Therefore, the general recommendation is to focus on the front sight. The rear sight and target will be slightly out of focus, but will still  be manageable.

Image courtesy of the TN Handgun Carry Course

Proper understanding and use of sights is an essential part of accuracy. As Colonel Townsend Whelen said, "Only accurate rifles are interesting."

In a future post I'll discuss the difference a Red Dot sight can make.

Good luck, and safe shooting.

Saturday, December 3, 2022

Follow-Up Reports

Not actually Erin.
& is used with permission.
Herein is an assortment of further information on topics I've discussed earlier. 

I am pleased to report that using this as an uninterruptible power supply for my CPAP works perfectly. Last month our neighborhood lost power from early morning until about 1 pm, and I didn't experience a change in performance as the Freeman 600 switched from pass-through charging to onboard battery. I am very happy with how this system operates, so unless there are hidden issues with the unit which only crop up after months or years, I consider this experiment a resounding success and recommend the Freeman 600 for all my CPAP-using brethren. 

I haven't yet tested the recharging speed/capabilities of the solar panels. That's on my list of "Things I want to do but first need to find the time to do them."

The Caretras Bunion Splint is doing its job of pulling my toe back into alignment while I work at my desk or watch television. However, the velcro doesn't hold as tightly as it once used to do, despite having been laundered and the hooks free of any lint. However, I have achieved a workaround with something I ordered for a different problem.

This 20-piece set of velcro ties for cable management works a treat for keeping the splint on my foot. The smallest (8" long) wraps around my big toe, and the next smallest (12" long) secures the brace around my instep. I have plenty of each, so if these start to fail I can just use the others, and I still have straps left over to secure the cables I wanted gathered up.

On a related note, I have discovered that wearing these gel toe separators while going for walks or running errands is a useful preventative measure. While they don't prevent my toe from cramping, they reduce the intensity of the discomfort and the time required in the splint to correct it.

Back in 2018 I mentioned using Hickies-brand no-tie shoelaces for my daily shoe and boot usage. As it turns out, while version 2.0 is more durable than version 1.0, they do still experience material fatigue and failure from repeated use. 

However, I have found something better! Lock Laces are a single strand of elastic cord with a spring-loaded lock to gather them tightly into place. This keeps them securely attached to my feet, but with enough "give" that I am able to quickly slip them on and off as needed.

There is even a heavy-duty boot version

I have been using Lock Laces for almost a year now and they continue to stretch and return to form. While I am certain the elastic will eventually fail, they have stood up to daily wear & tear and I am impressed with their durability and performance. I recommend them to anyone who wants to be able to save time putting on or taking off their footwear. 

That's all for now, but I will update you on any changes. 

Wednesday, November 30, 2022

Prepper's Armory: Iron Sight Types

The earliest firearms were simply pointed rather than aimed, but as technology matured and new concepts were developed, sights started to appear. At first they were similar to what we would think of as shotgun sights today: more of a guide to make sure the shot went in the right general direction than an actual sight for accurate shooting. As rifled arms became more common, however, better sights were needed.

Some of the earlier styles of iron sights are still with us. For example, the Patridge sight (no, not partridge like the bird) was named after 19th century target shooter and inventor E. E. Patridge and consists of a square post front sight and a rectangular notch rear sight (figure B in the illustration below). Nearly every iron sighted pistol, and many rifles, still use this design.

There are also more recent additions to the handgun iron sight family, such as the Steyr Trapezoidal sight  (figure G in the illustration below). Similar to the Patridge system with a front post and rear notch, the difference here is the shape of those two elements. The front sight is pyramidal, while the rear sight has a similarly-shaped cutout.

A selection of open sights, and one aperture sight suitable for use with long eye relief:
A) U-notch and post, B) Patridge, C) V-notch and post, D) Express, E) U-notch and bead,
F) V-notch and bead, G) trapezoid, H) ghost ring. The gray dot represents the target.

The Buckhorn and Semi-Buckhorn are named for the curved elements on the rear sight that extend up and around, containing the view of the front sight. The arms of the Buckhorn come close to meeting at the top, while the semi-Buckhorn is more open. While the former version of this sight has fallen from common use, the latter style is still frequently found on modern production lever action rifles.

For anyone who's ever attended a Cowboy Action match with a long range component, they've probably seen shooters using a tang-mounted aperture sight, sometimes called a Vernier sight. By positioning the rear sight on the wrist of the stock, it gives a much longer sight radius than the usual rear sight location near the chamber of the barrel, and can be removed or folded down when not in use.
It is a precision mechanism, and was one of the earliest finely-adjustable precision rifle sights available.

This sighting system is complemented with the addition of one of a variety of front sights, usually inside a protective tube or hood and frequently combined with a spirit level for consistent levelling of the rifle. This sight is mounted at the traditional location, the muzzle end of the barrel.

Receiver sights were, as the name implies, mounted to the side and top of the rifle's receiver. These sights, also commonly called peep sights, allowed hunters to make accurate "snap shots" relatively quickly, even in low light conditions. As with the tang sights, many receiver sights were also capable of precise adjustments. This style of sight is the conceptual predecessor of our modern Ghost Ring sight.

There have been more sight designs over the years in addition to these. Some withstood the test of time, while others did not.

In my next post I will explain how to look through the sights and put them on the target, aka sight alignment and picture. 

Friday, November 25, 2022

Finding the Angle

Not actually Erin.
& is used with permission.
Special thanks to George Groot for double-checking my math and helping with clarity. 

I realized that my previous post referenced using azimuths to find an angle without explicitly showing how to do that. I will attempt to explain the process, but please understand that math is not my best subject, and I may flail verbally about while trying to make my point. 

Triangulation is a process used in surveying and navigation which uses triangles (hence the name) to determine the coordinates of a point. You need two known angles and one known side length (or distance) to do this, creating a triangle which allows us to use trigonometry to solve for the other angles and distances.

Let us assume that you need to find the distance to the boat in the illustration above. How do you do that without a rangefinder?

1) Starting at point A, shoot an azimuth to the boat and record it. 

2) Using your compass, you turn right 90° and march toward point B. I recommend 10 yards, as it is a short enough distance that your bearing will not vary too much, and it is a nice round number that ought to make math easier. 
How will I know when I've traveled 10 yards? If you're doing land navigation, you should know your pace count per 100 yards, so just divide that by 10 and when you've walked that number of paces, you have arrived. If you don't know your pace count, this article by Lokidude will show you how. 
If the object is quite large, you might need to take more steps; I still suggest you take them in units of 10. 
I am making this slightly more complicated than it strictly needs to be, because you will need to have a straight line (d) coming from the boat that intersects line AB at a right angle. If you don't have a right angle, things will be much more complicated and outside the scope of this article, so I'm having you do a little more work now to save you a lot more grief later. 

This is the same reason I'm not having you walk until you're at 90° to the boat. What is the likelihood that you'll correctly make a 90° angle the first time? To my mind, this extra step prevents that mistake. 

3) At point B, shoot a second azimuth to the boat and record it. 

4) Shoot a third azimuth to point A and record that. 

5) In a triangle, no single angle can be more than 90°, and we're going to create a 90° angle in a moment, so angle ß cannot be larger than 90°. If it is, then subtract it from 180°. If it isn't, then subtract it from 90°. 

6) You now know angle ß. Record it. (For this example we will say it is 60°.)

7) Halve the distance of line AB to create two right-angle triangles which share a side, d. Side d is the distance you need to determine. 

8) You know the distance from B to D (the halfway point between A and B) is 5 yards. You know the measurement of angle ß. This is all you need, so now let's do some math. 

9) How much do you remember from Geometry?

We need to find the length of d, which in this figure is the Opposite side. The tangent of angle ß is the quotient (the number you get as a result of division) of the Opposite over the Adjacent. 
Side note: if you ever forget, just remember SOH CAH TOA:
  • Sine is the Opposite over the Hypotenuse (SOH)
  • Cosine is the Adjacent over the Hypotenuse (CAH)
  • Tangent is the Opposite over the Adjacent (TOA)
But we don't need to find that angle, because we know it. So we do some math jiggery-pokery:
  • Tangent of Θ = O/A
  • Multiply both sides by A 
  • A times tangent Θ = O
Which is exactly the same formula which David's friend gave us here, just with different names for the sides. 

So going back to the original problem with sailboat distance:

We know the distance from B to D is 5 yards. 

We know the measurement of angle ß is 60°. 

Therefore, 5 times the tangent of 60° will give us the length of line d, the distance to our target. 

The tangent of 60° is 1.73205080757. Shortening that to 1.73 ought to suffice. 

Therefore, d = 5 * 1.73. 

Therefore d -- the straight line distance from shore to boat -- is 8.65 yards.

The Right Angle Theorem says that the length of the side opposite the right angle is the square of the sum of the squares of the other two sides. In other words, the famous A² + B² = C², where C is the side opposite the right angle, also known as the Hypotenuse. 

Therefore, 5² + 8.65² = C². 

Therefore, 25 + 74.8225 = C². 

Therefore, C² = 99.8225. 

Take the square root of both sides. 

C = 9.9911 yards. 

So the distance from your current position at point B to the sailboat is almost 10 yards, or 30 feet. 

This makes good intuitive sense, as solving for all angles shows that we originally had a 60/60/60 equilateral triangle, in which case the distance between A and Boat and B and Boat must be the same as the distance between A and B.
Remember, we know that we have a 90° angle and a 60° angle, and all angles within a triangle must add up to 180°, so 90 + 60 = 150 and 180 - 150 = 30, therefore the remaining angle opposite side DB must be 30°. 

Since this triangle is half of our original one, the other half must be symmetrical and therefore identical. Therefore, the angle opposite side AB is 60°. 

George Groot adds:
We can exploit this feature of angles without using a compass for short distances, such as distance across streams or small rivers, simply by using the bill of a cap to align with the distant shore and  then turning to face a point on land without moving your head. The bill of the cap swung in an arc, and the arc describes the same distance (a radius) from the central point, letting you determine a distance that you can’t walk to by walking to a point on the same arc that you can reach. This is much less math than using triangulation to find the distance, and much quicker to determine things like "Do I have enough rope to make a rope bridge?"

If trigonometric functions are confusing, an alternate way is to use "minute of angle math" to determine the distance. Starting at point A, shoot an azimuth to your unknown distance target. Turn 90 degrees to walk parallel to the target for a known distance and shoot a second azimuth to the target. Subtract the smaller angle from the larger angle to get the "inside angle" of the target to your known distance. 

Since one minute of angle is roughly one inch at one hundred yards, if your known distance was 10 feet (120 inches) and your angle was 1 degree (60 minutes) you know that your unknown distance to the target is 200 yards away (60 minutes = 120 inches at 200 yards). This method requires a precise compass, and precise linear measurement, but it does work. 

Thursday, November 24, 2022

Shooting Azimuths

Not actually Erin.
& is used with permission.
Two years ago, David Blackard wrote a post about how to determine the distance to an object in the field without using a rangefinder. This involved knowing the distance and angle to another object and then using a calculator to do some complicated math. 
  1. In the drawing, aligning the start point with the target and then laying out a 90 degree angle for the base is important. 
  2. Measure as accurately as possible along that 90° angle to establish the base, shown as X.
  3. Here is where being able to get good angle measurements is important, since this will give you the vital number that plugs into your distance equation.

This is all very well and good, but in the un-edited version of his post he talked about using a protractor to find that angle. My immediate thought was "Why not just shoot an azimuth using a lensatic compass?" Well, it turns out that David had never heard of azimuths or lensatic compasses at that point, so I sent him some links and considered the matter solved. 

As it turns out the matter is not solved, because today David posted this:

In the comments, a friend said "I have no idea what you're talking about either, but I'd love to find out." I had a bit of time, so I started briefly explaining, and by the time I was done I had a good start on a blog post, which I figured I might as well finish here. 

What is an Azimuth?
Azimuths are used in astronomy and celestial navigation (which is just astronomy with more math) in addition to land navigation, and most explanations will give a complicated answer about three dimensions. Land navigation only uses two dimensions so a simpler application gets a simpler definition. 

Put simply, an azimuth is a compass bearing. Due north is 0°, so east is 90°,  south is 180°, and west is an azimuth of  270°. You get the idea: an azimuth is the angle between north and wherever you're looking.

What is a Lensatic Compass?
You've likely seen a lensatic compass before even if you don't know the name, as it has a very distinctive shape. Rather than describe it, here is a picture with the parts labeled. 

Land Navigation Module 2 Using a Lensatic Compass.

A lensatic compass has a useful feature where you can look through it to precisely align it with a terrain feature, then glance down to see what your azimuth to that feature is. 

Why a terrain feature? Because if you navigate towards a terrain feature instead of a compass bearing, you walk faster and safer, because your eyes are looking at where you're going rather than buried in the compass. Just be sure to check your compass every 100 yards or so to make sure you're still headed in the right direction. 

How to Shoot an Azimuth
Using a compass to find an azimuth is called "shooting", because if you do it properly you hold the compass like a firearm and aim at your target terrain feature. 

There are other ways to do it, but this method, known as the "cheek hold", is the most precise.
  1. Put your thumb through the loop with your forefinger pointing alongside the compass, as shown in the picture.  
  2. Bring your hand up to your cheek with the base of your thumb in the crease between your cheekbone and upper lip. 
  3. Look through the window in the compass cover and find your target terrain feature
  4. Line up the notch (rear sight) with the wire (front sight) and center the feature in the sights the same way you'd aim a gun.
  5. Glance down through the magnifying lens to find your azimuth.

In this example the compass reads 320°, so that is your azimuth. If you want to make your life easier, rotate the bezel ring so that the luminous line is aligned with your compass arrow. With that done, you can quickly check your bearing without having to shoot a new azimuth by aligning the arrow with the line and seeing if the fixed black line is still pointing at your target. If it is, you keep walking. If it's not, something has gone wrong and you need to shoot a new azimuth. 

Back Azimuths
If you need to go back the way you came, you don't need to shoot a new azimuth. Instead, you can calculate a back azimuth:
  • If the original azimuth is less than 180°, you add 180° to get a back azimuth. 
  • If the original azimuth is greater than 180°, you subtract 180° from the original azimuth. 
In the example above, the original azimuth is 320°, which is greater than 180°. Its back azimuth is therefore 320 - 180 = 140°. 

With a quality compass and the knowledge of azimuths, you can make very precise measurements in the field. Combined with the formula above and a calculator with the TAN function, you can quickly determine the distance to an unknown point. 

Wednesday, November 23, 2022

Prepper's Pantry: Preserving Herbs and Spices

Now that harvests are pretty much complete in most of the country, it's time to start preserving our harvests. In previous posts I've talked about the equipment and process of canning, pickling, and a brief overview on spices.

Dealing with herbs and spices is fairly simple, or at least it can be. As with any food preservation process, making sure the produce is of best quality is the most important first step. Once they've been examined, sorted, and rinsed, we can move on to preservation, with different options available depending on the type of vegetation we're dealing with. Dehydrating and freezing are the two most common options, so I'll focus on those processes here.

Dehydration can be handled in an oven, an air fryer, or a dedicated dehydrator. If using a dehydrator, it's recommended to get one with a fan as that will considerably reduce the time required.

As with any other form of dehydration, the trick is to get as much moisture out as possible without burning or singing the product. This is one of the benefits of a dedicated dehydrator, as they generally operate at a relatively low temperature.

Before dehydrating the checked and cleaned vegetation, the next step will depend on the herb or spice in question. Those with smaller leaves, such as oregano or rosemary, get processed on the branches, while those with larger leaves, such as basil or bay, are separated from them. Parsley simply has its stems trimmed.

Once sufficiently dried (and if appropriate, the leaves removed from their branches) the next step is storage. Depending on intended use, they can be left relatively whole, crumbled by hand, or run though a spice grinder or spice mill to get more of a powder-like product.

Regardless, they need to be properly stored, since oxidation is the enemy. For ready use, spices and herbs can be placed in small, airtight jars and stored in a cool, dark place. Adding an oxygen absorber to each container can help preserve freshness. Longer term storage should be in vacuum sealed bags, also containing oxygen absorbers, and still placed in a cool, dark place.

A selection of dehydrated herbs from the author's pantry

Another option for some leafy herbs is freezing. The leaves are separated from the stems, rinsed, and then layered in slightly damp paper towels, before being packed in Ziploc or vacuum sealed bags. These get labeled with the date and put in the freezer. Since no moisture is being removed (in fact, more is being added), herbs stored this way should be used within a few months at most; otherwise, too much flavor will be lost to freezer burn.

There's no point to growing our own herbs and spices if we lose them to spoilage. Hopefully, these tips will keep them fresh through the long winter months to come.

Tuesday, November 15, 2022

Cold Frames

Now that our gardens are at rest for the winter, we have time for additional garden-related projects, such as building some cold frames. These are transparent-topped, low enclosures that are used to protect plants from cold and wet conditions, like miniature greenhouses. The sides reduce the effects of cooling from wind, the top lets in light, and the whole thing limits heat loss through convection, especially at night.

Cold frames were traditionally built out from the walls of full greenhouses, and were used as part of the acclimatization of plants from the protected environment of the greenhouse to being fully outdoors. Seeds would be started in the greenhouse, and when big enough they would be moved to the cold frames, then finally to the garden. This gradual change improved survival rates considerably.

In addition to transitioning young plants in spring, cold boxes can also protect plants from early frosts or other weather conditions throughout the growing season.

Construction of these handy structures can be fairly simple. Although kits that only need basic assembly are available, cold frames sit at the lower end of complexity as DIY projects. They can even be made entirely out of recovered materials, such as pallets and plastic sheeting.

The sides are slanted and joined to a higher back and a lower front,  ensuring the top is angled to help with water runoff. Any clear or translucent panel can be used as a lid, making this a great way to repurpose old windows, or glass doors for larger frames. The top can be hinged for easy opening, or simply latched in place. 

A cold frame can even be converted into a hot frame with the addition of a heat source, such as an outdoor rated heating blanket or heating coil.

A variety of crops respond well to containment in a cold frame, including lettuce, parsley, onions, spinach, radishes, turnips, and so forth. Depending on the size of the cold frame, one type of crop can fill the entire space, or multiple plants can be grown so they produce in sequence to ensure a more constant flow of vegetables.

When placing a cold frame, make sure the top is facing south to get as much sun as possible. If high winds are a concern, having a way to stake the frame to the ground is helpful; a few large U-Nails set into each side allow a plant stake to be run through them and into the ground.

Whether starting young plants or protecting mature ones, cold frames are a cool project for the home gardener.

The Fine Print

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