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Pursuit of proficiency in the manly arts, like maps and knots and locks and guns.

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Here’s what’s going on in the manly arts, from the GridScout™ team.

Solar navigation with analog watch & pocket knife

TL;DR – A Russian-style 24-hour watch, aligned with the equatorial plane and aimed with a knife blade, makes a fantastic solar compass with 3° accuracy. Your inferior 12-hour watch will do fine too, with a bit of trickery.

You probably already know some basic solar-navigation concepts, but these are only rough approximations of the truth.

  • The sun rises in the east and sets in the west.
  • The sun is directly south at noon.

These approximations can be plenty misleading, so let’s just call them LIES. Here I present actual truths about the position of the sun and a far better way to use it to find directions. No equipment necessary except an analog watch and a pocket knife.

Skip to the action

Lie #1: The sun rises in the east and sets in the west.

At my home near the 43rd parallel, trusting that the sun rises in the east can mislead a fella by up to 34° in winter and summer. It’s even less accurate at higher latitudes. Here’s how it actually works:

Twice a year, at the equinoxes, the sun rises due east and sets due west. But both the rising and the setting deviate northward as we approach the June solstice, and southward for the December solstice. You’ll get at least 25° of deviation at each solstice, depending on your latitude. Inside the polar circles, the sun won’t rise or set at all, it’ll only circle around you just above or below the horizon.

Lie #2: The sun is directly south at noon.

Yeah, okay, but when is noon? Do you trust the government to tell you? Ha! Today my solar noon came at 13:42, not 12:00.

Don’t forget, of course, that in parts of the world the sun is north at solar noon. And in the tropics, it alternates.

True directions with a reverse sundial

Now that we’ve got those directional lies out of the way, let’s discuss how to find the truth. The hour hand of a 24-hour analog watch follows the apparent path of the sun very well as seen from above the north pole. So with proper alignment, it comes in handy as a solar compass. With a little trickery, even a 12-hour watch will do.

But first you’ll have to know two things: your latitude, and what time on your watch corresponds with solar noon. You can calculate solar noon or look it up. Use 12:00 as a rough approximation if you must, or 13:00 during daylight saving time.

One way to identify solar noon is to observe the shadow of a vertical pole over time. At solar noon, the pole’s shadow will be at its shortest of the day.

Next, you’ll align your watch as a reverse equatorial sundial. Once aligned, you’ll know which direction you’re facing because a sundial only reads the right time when it’s facing a particular direction. Whereas sundials are usually pointed in that direction and then used to determine the time, they work equally well in reverse.

Read on to find out exactly how to navigate with just an analog watch and a pocket knife.

Skip to 12-hour navigation

Navigation is easiest with a 24-hour dial that shows daytime hours at the top and nighttime at the bottom. This arrangement is common in Russian military watches, and it generally allows you to navigate without removing the watch from your wrist.

(when at or north of the equator)

  1. Position the watch dial vertically with the solar noon time at the top.
  2. Tilt the dial forward by an angle equal to your northern latitude.a
  3. Rotate your body till the hour hand points toward the sun.b
  4. You’re now facing southwardc.

a Just eyeball it, aiming to get within 6°.

b If the sun is north of the equator, you can use a knife blade to cast a shadow on the hour hand as an alignment guide. Otherwise, it may still be helpful as an extension of the hour hand.

c If you happen to be on the equator at solar noon on an equinox, then all directions will seem to be south. Wait ten minutes.

(when south of the equator)

  1. Position the watch dial vertically with the hour hand at the top.
  2. Tilt the dial forward by an angle equal to your southern latitude.a
  3. Rotate your body till the solar noon position points toward the sun.d
  4. You’re now facing northward.

d When the sun is south of the equator, you can use a knife blade to cast a shadow on the solar-noon position as an alignment guide. Otherwise, it may still be helpful as an extended marker of solar noon.

Remember, it’s easier with a 24-hour dial. If you dislike bisecting angles or need an excuse to go watch-shopping, keep that in mind. But 12-hour watches are more common, so here’s how to make do.

(when at or north of the equator)

  1. Position the watch dial vertically with the solar noon time at the top.
  2. Tilt the dial forward by an angle equal to your northern latitude.e
  3. Identify the sun’s reference point on your dial. You’ll find it halfway from solar noon to the hour hand, searching leftward from solar noon in the morning or rightward in the afternoon.
  4. Rotate your body till the sun is aligned with its reference point.f
  5. You’re now facing southward.g

e Just eyeball it, aiming to get within 6°.

f When the sun is on your side of the equator, you can use a knife blade to cast a shadow on the dial as an alignment guide. Otherwise, it may still be helpful as an extended marker of the reference point.

g If you happen to be on the equator at solar noon on an equinox, then all directions will seem to be south. Wait ten minutes.

(when south of the equator)

  1. Position the watch dial vertically with the hour hand at the top.
  2. Tilt the dial forward by an angle equal to your southern latitude.e
  3. Identify the sun’s reference point on your dial. You’ll find it halfway from the hour hand to solar noon, searching rightward from the hour hand in the morning or leftward in the afternoon.
  4. Rotate your body till the sun is aligned with its reference point.f
  5. You’re now facing northward.

How accurate is watch-based navigation?

Almost perfectly accurate in theory, and plenty accurate in practice. You can reasonably expect to limit your maximum error to 3°.h As with any other reverse equatorial sundial, accuracy depends primarily on your identification of local solar noon and on fairly good alignment of your watch dial with the equatorial plane.

h Assuming up-to-date knowledge of solar noon. Make that 7° if you use mean solar noon. The distinction is given below.

Solar-noon error

I presume that your watch is set to civil time. 12:00 civil time is the average clock time at which the sun passes a particular government-specified meridian. A useful reference, but it rarely coincides with the actual solar noon of your location. Due to irregular time-zone borders and daylight saving time, civil time can easily be off by two hours, sometimes more.

The time on your watch that corresponds with solar noon will also vary a bit over the seasons due to Earth’s elliptic orbit, so you may just want to remember what time it comes on Christmas Eve. That’s mean solar noon.i It’ll get you within 16 minutes, or 4°.

i Mean solar noon also coincides with solar noon on April 15, June 15, and September 1.

Equatorial-alignment error

For the most accurate readings, the dial of your watch should be parallel to the plane at the equator which bisects Earth into its two hemispheres. If you hold your watch horizontallyj like an amateur, you’ll add up to 45° of error at the edge of the tropics or 21° in northern USA.k But if you can hold it within 6° of proper alignment, a goal easily met by eyeball, then your maximum directional error due to equatorial misalignment shrinks to just 2°.

j Other instruction on navigating with a watch assumes that equally spaced markings are suitable for a horizontal sundial. I’m right and they’re wrong.

k These errors peak on the summer solstice, eastward three hours before solar noon and westward three hours after.

Where to, then?

Although useful anywhere with sun, watch-based navigation is particularly well suited for a summertime polar expedition. The sun is up all day, the equatorial plane is conveniently near horizontal, and the sun is on the right side of it to cast a knife-blade shadow on your dial. Handy, since magnetic compasses are useless inside the polar circles.

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Tying the zeppelin knots

The zeppelin bend is a good knot for joining two ropes together. The zeppelin loop is a good knot for making a fixed loop. This is how I tie them.

Zeppelin bend

This bend won’t slip or shake loose, ever. It reduces the breaking strength of a rope by only 25%. And it remains easy to untie after being subjected to an extreme load, although not while loaded. To tie it:

  1. Take one end of each rope, and drape them over your index finger as illustrated.

  2. Take the end of the left rope under its standing part, over and under the end of the right rope, then back under itself to form an overhand knot around both ropes.

  3. Take the end of the right rope around behind the index finger and _under both ropes to form another overhand knot around them.

  4. Pull the standing parts, then the ends.

For contrast, consider that the sheetbend reduces a rope’s breaking strength by a whopping 55% and that in synthetic rope it slips before even reaching that limit. I recently tested the security of the zeppelin bend, the sheetbend, and six other bends. See how they compare.

Zeppelin loop

This fixed loop knot shares the zeppelin bend’s excellent qualities. To tie it:

  1. Tie an overhand knot some distance from the end of the rope, then pass the end around an object (optionally) and back through the far opening in the overhand knot as illustrated.

  2. Pass the end through the loop as illustrated.

  3. Pass the end through the near opening in the overhand knot as illustrated and under its own standing part.

  4. Pull the standing part, then pull the end.

A worthy alternative to the mediocre bowline loop, the zeppelin loop is derived from the zeppelin bend in the same way that the bowline is derived from the sheetbend.

Comment

Uncle Sam wants YOU for U.S. Militia

The Second Militia Act of 1792 was passed by the second U.S. Congress and President Washington. It requires each of us dudes to “be enrolled in the militia”; to “provide himself with a good musket or firelock, …bayonet, [and] not less than twenty four cartridges…; or with a good rifle, …twenty balls…, and a quarter of a pound of powder”; and to “appear so armed … when called out to exercise or into service”.

This mandate still applies. It has been lawfully amended to apply even more broadly. Arm yourselves well, and be ready. It’s your duty.

There are those who claim that other supposed laws supersede this statute and even that they override the Second Amendment to the U.S. Constitution. They would mandate the opposite, that you be disarmed and useless in the defense of your family and community. That is absurdity.

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Taut-line showdown

Friction-loop knots, several of which go by the name taut-line, are adjustable loops commonly used to make guy-lines easily tensioned. They’re handy when you need to support a tent or hammock, tie an aircraft down, or fix a telescope in orbit. You know, everyday stuff.

But there are several variants. Which friction loop works best? I tested eight of them in parachute cord, and here are the results.

I used no special equipment. Just hands and feet and rope. To compare the grip of two knots, I simply tied both in one rope to what felt like equal tightness and then pulled to see which would slip first. I tied and tested each knot at least three times. Simplicity scores are inversely related to length of rope required.

Rank Friction-loop knot Grip Simplicity Tightening ease Overtightening resistance
1 Cawley hitch ★★★★ ★★★★ ★★★★ ★★★★★
2 Ezelius loop ★★★★★ ★★★ ★★★ ★★
3 Blake’s-hitch 5/3 loop ★★★★★ ★★ ★★★★
4 Rolling taut-line +1 ★★★★ ★★★ ★★
5 Midshipman’s hitch ★★★ ★★★★ ★★
6 Magnus taut-line +1 ★★★ ★★★ ★★
7 Rolling taut-line ★★ ★★★★ ★★
8 Magnus taut-line ★★★★ ★★★

The most common friction loops are the midshipman’s hitch (for sailors), the rolling taut-line hitch (for landlubbers), and the magnus taut-line hitch (for pilots). The “+1” taut-line variants have an extra turn before the finishing half-hitch.

Winner: CAWLEY HITCH!

The Cawley hitch seems to be the most practical of these friction loops. It’s one of the easiest to tie and uses the shortest amount of rope. It’s the easiest to tighten to the point where it grips well and gives confidence that it won’t shake loose. And it seems to be impossible to overtighten this knot to the point where it becomes hard to adjust the tension of the rope.

So just as the best Mustang is a Camaro and the best apple pie is made with peaches, the best version of the taut-line hitch is actually the Cawley hitch.

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Knots in the dark

Inspired by naval demolition trainees tying knots —albeit inferior ones— underwater, and also by firefighters doing it in thick fireproof gloves, I present to you the GridScout™ tactile knot-tying challenge!

Challenge

Darkness may be a more practical obstacle. So, periodically, in a completely dark room or with your vision of the rope otherwise obstructed, test your ability to correctly tie each of the following knots.

Don’t let me talk you out of tying knots underwater. You should totally do that too.

  1. Double constrictor knot. In lieu of the inferior clove hitch or right-angle knot.

  2. Simple-Simon-under bend. At least 200% more secure than the sheetbend.

  3. Alpine butterfly. Excellent as a mid-rope loop, or as a “shank” to bypass a section of rope, or as a “bend” to join ropes.

  4. Zeppelin loop. A fixed loop for the end of a rope, better than the bowline in every way.

  5. Cawley hitch. A far more secure alternative to the taut-line hitch.

If you can properly tie great knots like these without even looking, then you’re good to go. It may not be as sexy as splicing det cord or as cool as hoisting a carbide chainsaw up to a rooftop; but it’s sexy enough, cool enough, and downright useful in everyday life.

Additional reading

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Good knots for bungee line

Bungee line and other super stretchy cordage can’t be fastened securely with traditional knots. They often slip at just 10% of breaking strength. But here are a few knots that work exceptionally well in bungee line.

Fixed loops

Bends

  • Vice-versa bend. Use for joining two bungee lines. The ends are tidily parallel to the standing parts, convenient if you have to reeve the knot through an eye. Fairly difficult to untie after heavily loading.

  • Zeppelin bend. Use in place of the vice-versa bend wherever ease of untying after extreme stress is valued more than tidiness.

Stopper knots

  • Stevedore knot. Based on the figure-8 but with an extra wrap, this is a moderately bulky stopper knot that stays put.

Additional reading

Comment

Which bends hold best?

A “bend” is a knot for joining two ropes together. Thinking that it would be helpful to know which bends do this job best, I took several pieces of my daughter’s fishing line and did a little experiment.

Experiment

In each line I tied a different bend, which I greased before pulling it tight. I then hung the resulting loop on a hook and suspended a canvas bag from it. I filled the bag with rocks till the fishing line either broke or slipped to a completely untied state. I then repeated the experiment and recorded the average mass of the bag of rocks that had caused the knot to fail.

I was most interested in measuring the “security”, or resistance to slipping, as opposed to breaking strength. That’s why I chose slippery material and made it even slipperier, hoping that each bend would slip before having a chance to break. But alas, some knots just won’t slip.

Results

Bend knot Security (kg of rocks)
Butterfly bend 5.4+
Zeppelin bend 5.4+
Simple-Simon DOUBLE 5.4+
Simple-Simon UNDER 5.4+
Simple-Simon CROSSOVER 4.9
Simple-Simon OVER 4.0
Double sheetbend 3.3
Sheetbend 1.8

The ‘+’ symbol indicates that the knot’s slip limit, even tied in grease, exceeds the breaking strength of the line in which it was tested.

Conclusions

I love the alpine butterfly as a bend, a shank, and a loop. It’s versatile and easy to tie, so I’m happy to confirm that it refuses to slip.

The classic sheetbend and double sheetbend are the least secure of all bends tested. The former slips so easily in comparison that its use is hard to justify.

The Simple-Simon-crossover bend is my own creation. In this test it outperformed the Simple-Simon-over, on which it is based, by 23%. Since it’s no harder to tie, this is a satisfying discovery. But it still can’t compete with the security of the Simple-Simon-under, so I’ll stick with that.

Spotlight: Simple-Simon-crossover bend

This experimental knot is a variant of the Simple-Simon-over bend. The only difference is that the standing part and the working end of the first rope are swapped. The second rope is tied around a bight in that rope just as usual. Uniquely among the Simple-Simon knots, the rope ends are ultimately diagonal from each other.

Simple-Simon crossover

The result is that the bight of the first rope is clamped just as in the Simple-Simon-under bend without the relative difficulty of making a pass under the rope. I wanted to see how this knot fares against the other Simple-Simon knots.

The Simple-Simon-crossover does seem to be more secure than the Simple-Simon-over against slippage of the inner bight around which the other rope is wrapped. Its resistance to slippage of the wrapped rope, however, is unimproved by this variation. This leaves the overall security at least slightly inferior to that of the Simple-Simon-under.

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New MGRS grid overlay

Since Google put Gmap4™ out of business, we’ve been lacking an MGRS grid on our aerial views. But as of today, GridScout Map™ now uses GISsurfer™, making it easier to correlate points on these photographs with those on our paper maps.

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Knots that actually hold

Some knots in common use have never been all that good. Others have grown less secure as we’ve turned to synthetic ropes. These ropes are strong and resist rotting, but they’re a bit slippery. So we just can’t keep depending on knots that kinda sorta worked with the tarred hemp ropes of the 19th century. Here’s a list of loops, shanks, bends, bindings, and hitches that’ll actually hold in modern rope.

FYI, the worst offenders are the sheepshank, sheetbend, half-hitch, clove hitch, and shoelace knot.

Fixed loops

  • Zeppelin loop. Use at the end of a rope in place of bowline loop.

  • Flemish loop. Use at the end of a rope or in the middle. One of the fastest fixed loops to tie and, with its figure-eight shape, the easiest to verify. A bit of a pain to untie after stressing though.

  • Alpine butterfly loop. Use in place of Flemish loop in the middle of a rope, if ease of untying is important.

Shanks

  • Butterfly shank. Use alpine butterfly in place of sheepshank, which is the best known but most unreliable of shanks, lest you die.

The point of a shank is to bypass a section of rope that is damaged or overly long. A shank that easily shakes loose obviously won’t do.

Bends

  • Simple-Simon-under bend. Use in place of sheetbend for joining slippery or dissimilar ropes. About as easy as the name suggests. Its ends are tidily parallel to its standing parts, convenient if you have to reeve the knot through an eye.
  • Vice-versa bend. Use in place of sheetbend for joining stretchy rope. Tidy like the Simple Simon.
  • Butterfly bend. Use alpine butterfly in place of sheetbend wherever ease of untying after extreme stress is valued more than reevable tidiness.
  • Zeppelin bend. Use anywhere that you might use the butterfly bend, especially in stretchy rope. The least reevable of the bunch, but the most easily untied.

I tested the security of eight bends for comparison. See results.

Bindings

  • Double constrictor knot. The most manly of bindings. Use in place of clove hitch or right-angle knot. The old-timers say you have to cut it off; but with synthetic rope, untying is often perfectly feasible.

  • Slipped double constrictor knot. Use in place of clove hitch as a secure but easily untied binding.

  • Reef knot. Also ambiguously called a “square knot”, this is a good knot for binding against a convex surface – such as for reefing a sail, tying a sack shut or fastening your short-laced shoes.

The other “square knot”, so called by the British, is the Chinese friendship knot. It is decidedly the more square of the two.

Never use a reef knot away from a convex surface or for joining two ropes. That’s what a bend is for. Misusing a reef knot as a bend may get you killed.

  • Double-throw reef knot. Variant H2H2s of the surgeon’s knot. Use in place of reef knot against flat or concave surfaces.

Unlike the standard reef knot, the double-throw variant is suitable as a bend. That’s why it can handle non-convex surfaces. But its best use is as a binding knot because, although it tightens well against a bindee, other bends significantly outperform it in jam-resistance and in maintaining rope strength.

  • Two-bight reef knot. For a decorative shoelace bow that’ll stay tied all day: first fold the ends over to form two bights, then simply tie them in a reef knot.

  • Freedom bow. A quick-release bow knot that keeps a man’s shoes well tied, in defiance of the king’s bidding, until he chooses himself to loosen them.

Most people use a standard shoelace knot (double-slipped reef), but it works loose easily. The reef knot’s grip seems to rely on its symmetry, and using bights for only half of the knot breaks that symmetry. The two-bight variant gives up the quick-release option in order to retain the symmetry. The freedom bow, on the other hand, makes up for its asymmetry by converting the half-wrap around each loop into a full wrap.

Hitches

  • Double constrictor knot (or slipped variant). This binding serves well as a simple pole hitch.

  • Cawley hitch. A good friction loop. Use in place of the midshipman’s hitch or taut-line hitch, for use in tensioning guylines or for mooring a boat to a tree. To tie down an aircraft, use nested pairs of Cawley hitches.

I tested eight friction loops for comparison. See results.

  • Cleat hitch. The right way to moor a boat to a dock.

  • Schwabisch hitch. A very good closed-system hitch for connection to a life-support line, in case you fall when climbing crazy heights.

  • Stalactite hitch. A friction hitch with enough grip to pull on a heavily loaded line, relieving the tension on one end of that line so that its knot can be untied. Also useful anywhere that a lengthwise pull on a rope or pole is needed, even if that object is slippery or tapered.

My stalactite hitch improves upon the stability of the five-turn variant of the gripping sailor’s hitch by finishing with a riding turn around its diagonal part. This enables it to handle cycles of jerky tensioning and detensioning.

Compound knots

  • Trucker’s hitch (butterfly-Cawley variant). Use this compound hitch to secure a heavy load.

    1. Make a fixed upper loop with the alpine butterfly. Tie it far enough from your final anchor point to allow room for cinching.
    2. Pass the working end around the anchor point. This forms a lower loop.
    3. Hook onto the upper loop with a Cawley hitch.
    4. Adjust the Cawley hitch to tension the lower loop.

Different strokes for different ropes

Different types of cordage present different challenges.

Comment

Why we need guns

“A well-regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed.”

— Constitution of the United States, 2nd Amendment

We the People are responsible for our own security. That responsibility cannot reasonably be delegated to any government. I have two reasons for this position:

  1. It is infeasible for a government to provide adequate security to respond to immediate threats against each individual. The best it can do is to prioritize whom to protect. Forgive me if I’m uncomfortable with the notion of allowing my family and others around me to be deemed expendable when I myself am capable of providing security.

  2. It is highly dangerous to allow a government to entertain notions of superiority over its People, of a rightful monopoly on possession of certain property, and of the right to forcibly establish such a monopoly. Such an abolishment of freedom, if applied to possession of the weaponry necessary for our defense, will inevitably lead to more massacres and other atrocities. Whether these future attacks are perpetrated by private criminal entities or by the government itself, they pose a serious threat.

So let’s keep our security. Let’s remain free. Let’s not subject ourselves to violent attacks or to unjust rule which puts are lives in jeopardy. Let’s not ever give up our rightful defenses, no matter how nicely our leaders may try to paint that picture.

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Planning evacuation routes

If you should ever find yourself in need of evacuation, it’ll help to have planned a suitable route. This is how I do it.

Destinations

In addition to the primary destination, it’s important to have an alternate destination. Preferably in the opposite direction, as this maximizes the chance that the alternate destination remains viable when the primary becomes unreachable. To locate each destination on an MGRS map, consider using GridScout Map™.

Routes

While it’s helpful to know the fastest route, the route most useful here is actually the one that is fastest during peaks of traffic congestion. Think rush hour, with a few bad accidents.

In addition to your primary route to each destination, it’s important to have an alternate route in case the actual situation differs from the one in your imagination. Preferably along a path which has no overlap with the primary route, as this maximizes the chance that the alternate route remains viable when the primary becomes impassable.

As an example, let’s plan two routes from Sonna to Walters Ferry. There aren’t many good options for crossing the Snake River, but we can select bridges near Melba (primary) and Marsing (secondary). Then we can plan two routes which diverge immediately to separate highways and which do not meet at any point until we reach our destination.

Zombies don’t stand a chance against such cunning.

Comment

Aerial views reënabled!

A few months ago, Google put the non-profit Gmap4 service out of business. GridScout™ relied on Gmap4 for its aerial views, so that was a sad day. But yesterday I reënabled the aerial-view feature using Google Maps directly. It lacks the MGRS-grid overlay that we used to enjoy with Gmap4, but it’s still useful for confirming the relevance of a search result and checking its surroundings.

Update: We now have an MGRS grid again.

Comment

Google killed Gmap4! :O

Google recently changed its API usage policy, effectively putting the non-profit Gmap4™ out of business. That’s unfortunate, as Gmap4 was designed to benefit disaster-management organizations and was doing a great deal of good in that realm. Since GridScout Map™ used Gmap4 for its aerial views, that feature currently won’t work. While this does not affect GridScout’s primary goal of searching Google Maps and performing bulk collection of MGRS location data, it does make it harder to verify the relevance of unfamiliar search results. The maker of Gmap4 has made appeals to Google in hopes of coming to an agreement, but Google refused. In order to continue using the Google Maps API in his volunteer efforts, he’d have to shell out $46,000 per year. So Gmap4 is now gone. Bummer.

I am now considering alternatives to Gmap4, so that I can restore GridScout’s aerial-view feature.

Update: I replaced the aerial viewer.

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RC1 — a lightweight tactical carbine

I’m building a new weapon which I call the GridScout RC1. Why RC1? Because it’s easier to explain that RC1 stands for Reeder Carbine #1 than to explain that PK6 (its original name) stands for Piŝta Karabeno je 6,5 Grendel.

Weapon design

I want a gun that’s especially easy to handle in close-quarters combat without sacrificing effectiveness at medium range (up to 500 yards). While many PDWs are great in close quarters and a modern carbine is pretty good up to 300 yards, both are severely handicapped beyond that range. PDWs suffer from their very short barrels, while the typical carbine is held back by a diminutive 5.56x45 NATO cartridge. In either case, the energy of the bullet is insufficient to remain effective at my maximum intended distance against human targets and the occasional medium-size game animal. (Besides the obvious counterterrorism missions, I intend to hunt wolves, deer, and wild boar with this puppy.)

As an illustration that 5.56x45 won’t do, consider that at 500 yards it will have lost 68% of its kinetic energy, reducing it to just 541 ft·lb. While there’s no universal agreement on how much it takes to do the job well, I set my requirement at 800 ft·lb based on the guidance of Chuck Hawks. A 6.5 Grendel cartridge exceeds this slightly at 500 yards, giving 818 ft·lb; whereas the lighter and less streamlined 5.56mm cartridge can comply only out to 300 yards. (Calculations based on Wolf™ Military Classic cartridges — 6.5 Grendel, 100gr, 0.515 BC, 2723 ft/s MV; vs .223 Remington, 55gr, 0.395 BC, 3241 ft/s MV.)

I’d like to conquer these goals by creating a custom carbine, so I’m going for it. When it’s finished, we’ll see how it performs.

Basis

The RC1 design is based somewhat on the Alexander™ 6.5 Grendel Incursion, which is relatively light and fires one of the most effective general-purpose cartridges yet devised for modern sporting rifles. The Incursion, however, isn’t everything that I want it to be.

It’s slightly longer than I prefer in close quarters, and it still relies on the direct-impingement gas system that got M16 operators killed in Vietnam.

But thanks to the versatility and popularity of Eugene Stoner’s modular AR-15 design —upon which the M16 and the Incursion are based—, we now have a standardized means of interchanging parts to fit the needs and wants of the shooter. The RC1 will take advantage of this in two important ways.

  • Certain part selections, inspired by PDWs and by AR15A3-derived ultralight carbines, will serve to make the RC1 lighter and more maneuverable.

  • The bolt will be cycled by a gas piston, based on the Armalite AR-180 design, which has proven substantially more reliable than direct gas impingement.

Piston gas systems consistently outperform direct-impingement systems in reliability tests, as they did in a 2007 test by the U.S.Army.

Barrel

The barrel of the RC1 will be of the standard 16” carbine length, just long enough to avoid the red tape associated with a short-barreled rifle. This length also produces high enough muzzle velocity and bullet energy for practical medium-range use. If I use a muzzle brake, it will be a short, single-chamber model to minimize the added weight and length.

Buttstock

The RC1 will have a very short, fixed-length buttstock to shift its mass closer to the shooter’s body where it’s most easily supported. With the 33° grip angle that’s most common in modern carbines, this position would be uncomfortable for the wrist of the shooter’s dominant hand; so the RC1’s grip will instead be nearly vertical as in a PDW. This weapon will be as lightweight as practicable, in order to limit muscle fatigue so the shooter can more easily keep his sights steady on the target.

Sights

The RC1 will be equipped with two sighting systems:

  • A lightweight fixed-power riflescope, for 100- to 500-yard engagements
  • Simple offset iron sights for quick target acquisition within 100 yards

Progress

Progress on this project is as follows. With a scope and a full magazine, I anticipate a total weight of about 6 lb 13 oz, and a total length of about 32 inches.

This carbon-fiber buttstock, produced by Incognito Arms™ within spitting distance of my daily commute through Boise, weighs just 2.33 oz. The 13° Ergo™ Swift Grip (2.8 oz with included screw) notably has no backstrap, so the palm can grip the gun higher for recoil management and easier reach of the magazine release. I've also installed an Alexander™ Incursion melonited chromoly barrel (1 lb 7.9 oz), Aero™ barrel nut (1.3 oz), and TacStar™ handguard (7.3 oz with included hardware). The barrel came with an Alexander™ "hard-use" bolt assembly (1.5 oz), which in the absence of a bolt carrier is not yet installed.Total weight as pictured is 3 lb 5 oz. 2018-12 — Buttstock, grip, & barrel

Trigger-guard design courtesy of Gregory Spicer.

The lower is now complete. Total weight so far is 4 lb 9 oz. Projected total weight when complete and fully loaded is now 7 lb 3 oz. That’s 6 oz heavier than originally anticipated, so I better start workin’ out. ;)

Coming 2020-11 — Piston kit to complete the upper

Performance

When the RC1 is complete, we’ll assess its performance in a separate post, a link to which will be conveniently provided here.

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