SHTF blog – Modern Survival

How To Build A Dirty AR-15 Rifle

dirty ar-15 build

Preppers and survivalists alike need one go-to rifle they can trust through thick and thin.  This would be a rifle for everyday use and/or carry either hidden as an EDC gun in the back of a vehicle, in the rack of an ATV/UTV at the Bug Out hide away, and one that will be reliable though not always treated kindly or cleaned regularly.  We all need a dirty rifle. A “dirty rifle” then defined here for rather universal service would be (could be) an AR-15 in a very base model.  This is a rifle designated to be available to “bang around” though not overly or by any means the focus of intended abused.  After all, you want a rifle that will function every time it is loaded, charged, and triggered.

By Dr. John J. Woods, a contributing author

At the same time this would not be a rifle that was babied because it was the top-of-the-line model or decked out with all the bells and whistled as showcase illustrated on the cover of Recoil or Ballistic magazines, the Playboy of weaponry publications if you will.  This is a rifle that might make the issue of Mechanics Illustrated or Guns, Guts, and Cigars (I wish).

One Weapon of Choice

ar parts

For this project then we picked a sweet, ripe rifle.  It is the more or less common man’s Smith and Wesson Sport II Optics Ready AR.  It is a flat-top model sans any supplied open sights, attachment points, or gadgets. It comes with a Picatinny rail atop the upper ready to accept your fav choice of scope, red dot, or holographic.  This is as basic an AR as one can get, but still have some options to customize. The forearm is a standard AR round model, and the buttstock is a 6-position CAR variety.  One 30-round PMAG is supplied.  It is chambered for the 5.56 Nato/.223.  It sells at Academy for $599.99.  A “Best Buy” in my book.

Basic AR Rifle Specifications


The essential specifications on this rifle include an overall length of 35 inches, though remember its CAR stock adjusts to a shorter length.  The rifle’s finish is a black matte Armornite coating for resistance to elements and rusting.  This rifle has a gas operated system which is a standard AR build.
The barrel is made of tough 4140 steel and is 16 inches long with a standard M-16 type birdcage muzzle flash suppressor.  The trigger guard is integrally forged.  The firing pin is chromed to resist corrosion and to provide smooth, reliable operation.  The upper unit does come with a forward assist should the bolt/carrier group not want to close on the chamber.  The chamber/bolt area is covered by a hinged dust cover.

The top of the receiver upper unit is affixed with a Picatinny rail suitable for mounting any selection of optics including a conventional riflescope.  More popular these days are some type of red dot, electronic or holographic sight.  Even green dot scopes are growing popularity since shooters have discovered the green illuminated reticle is easier to see in dim or dark light. There is also a short section of Picatinny rail forward over the gas block to mount a front open sight should the shooter also choose to add an open sight at the rear as well.  This rifle offers two sling mount attachment points, one loop at the bottom of the buttstock shoulder rest, and a push button QD swivel attachment point under the front gas block.

Options a Base Rifle is Missing


You might look at the specs above and wince a bit at what this AR rifle does not have from the factory.  Let’s review those items to see what is really critical in a “dirty” rifle, or what could be added as an accessory or just run it as is. At first glance you are surely going to notice the lack of open sights on the Picatinny rail.  That could be a correct-O, no open sights. However, with ease you could add a set of Magpul or GG&G pop up open sights to serve as a backup (BUIS).  There is some argument for this, but again, we’re trying to build a bare knuckles rifle here.

While a few factory ARs do add an optical sight, honestly the majority of them are low grade, less than stellar product, so not much is really missed.  Anyway, you are going to want to add a top notch optics on this rifle as it primary sighting instrument. The CAR buttstock on this Smith and Wesson is bare bones.  It is even missing a plug to attach a push button sling connector.  The conventional sling loop works, but there may be other options to consider adding to the attachment point up front under the gas block.

There is no massive (heavy) quad rail on this AR specimen.  Remember we’re not going to add all that “stuff” anyway regardless of how cool it is, or functional.  If your knees go weak, you can add a multi-sided rail system later.  Make sure you need it.


best ar-15 grip

For this rifle, only two changes were made.  First, I swapped the Std-slick AR pistol grip for a grabbable Hogue handle.  Next I replaced the round polymer forend with a Magpul Carbine length version with M-Lok ports so I could add something else if I desired later. For optics, I am narrowing the choices between a Trijicon MRO or an Aimpoint PRO (Patrol Rifle Optic).  What we want is a point-n-shoot set up for a fast aimed response.  One is small, lightweight, the other more “combat” hardy.  What would you choose?

Again, a dirty AR is a trench gun.  It is intended for readiness and quick deployment, a rifle that every prepper and survivalist should consider as an EDC long gun.  Build one for yourself.

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