GridScout™ Blog | GridScout™


A tool for bulk collection of location data, including MGRS coordinates, to be used by intelligence analysts. Finally, MGRS search for Google Maps!

View on GitHub

GridScout™ Blog

This blog is dedicated to the proficient defensive use of MGRS maps, the GridScout™ Google-Maps client, and other tools well suited to the goals of GridScout™.

Subscribe: Atom feed

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.

Google put the kibosh on 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™ 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.

RC1 — a lightweight tactical carbine

The ultimate purpose of the GridScout™ map-search tool is to provide for a better community defense. For that same purpose, I’m building a new firearm. I call it the RC1. Why RC1? Because it’s easier to explain that RC1 stands for Reeder Carbine #1 than to explain that PK6 (my original name for the RC1 concept) stands for Piŝta Karabeno je 6,5 Grendel.

Weapon design

My intent is to create a weapon that is especially easy to handle in close-quarters combat without sacrificing effectiveness at medium range (up to 500 yards). While many PDWs are very good at close quarters and a typical modern carbine is pretty good up to 300 yards, both are severely handicapped beyond that range. The PDW’s biggest hindrance in this regard is its very short barrel, while the carbine is held back primarily by its use of the diminutive 5.56x45 NATO cartridge. In either case, the energy of the bullet is insufficient to remain very 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 weapon.)

As an illustration of the insufficiency of 5.56x45, consider that at 500 yards it will have lost 68% of its kinetic energy, reducing it to just 541 ft·lb. While there is no universal agreement on how much it takes to do the job well, I set my personal requirement at 800 ft·lb per the guidance of Chuck Hawks. A 6.5 Grendel cartridge exceeds slightly at 500 yards, giving 818 ft·lb; whereas the lighter and less streamlined 5.56mm cartridge can comply only out to 300 yards. (These calculations are all based on the Wolf™ Military Classic cartridges — .223 Remington, 55gr, 0.395 BC, 3241 ft/s MV; and 6.5 Grendel, 100gr, 0.515 BC, 2723 ft/s MV.)

I think I can more fully achieve my own goals by creating a custom carbine than by selecting any of the off-the-shelf offerings that I’ve already considered. So I’m going for it, and upon completion we’ll see how it performs.

Until we have those results, I’m just another guy on the Internet who thinks he knows everything. ;)


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 for close-quarters maneuvering. More importantly, 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.


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. The muzzle brake will be a short, single-chamber model to minimize the added weight and length.


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.


The RC1 will be equipped with two sighting systems:

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


Progress on this project is as follows. Initially, a few paper parts stand in for some of the major parts that I have not yet acquired. With a scope and a full magazine, I anticipate a total weight of about 6.8 pounds, and a total length of about 32 inches.

This Anderson receiver set (8.7-oz lower, 6.7-oz upper) from Wisconsin has no ejection-port cover and no forward assist, frills which frankly aren't worth their weight. The receivers are held together by 2A Armament titanium takedown pins made in southeast Boise, adding 0.1 oz. The TacStar 10" carbon-fiber handguard weighs in at 7.3 oz, mounting hardware included. I envision a short skeleton stock, a grip angle of about 14°, and about a 5X scope. 2018-07-05 — Initial concept

I've decided on this Japanese fixed-power 6X scope which, without mounting rings, weighs 9.8 oz. 2018-07-27 — Weaver K6 scope (paper model)

This carbon-fiber buttstock, produced within spitting distance of my daily commute through Boise, weighs just 2.33 oz. Compared to other stocks with an integral buffer tube, it appears to be the lightest on the planet. 2018-07-31 — Incognito Arms buttstock

This 5.9-oz Israeli magazine is made of steel, making it stronger than the aluminum USGI models that are prone to bending of the feed lips. Up until this point, the magazine in photographs has been a paper model, but the real magazines finally made it through customs. The grip is still paper but now represents a 13° Ergo Swift Grip. Most importantly, this grip lacks the backstrap of the Tactical Link PDW grip pictured previously, putting the palm higher for better recoil control and farther forward to make all all finger controls easier to reach. 2018-11-14 — E-Lander 17-round magazine (steel) & Ergo Swift Grip (paper)


When the RC1 is complete, I will assess the performance of this weapon in a future post. I’ll provide a link here to make it easy on you.

Subscribe to GridScout™ Blog: Atom feed