Occasionally I build duplicates of existing designs but, usually I try to come up with something original so, I need a concept to challenge myself to develop a unique configuration. Being a military firearms aficionado and collector, I have some idea what make a military rifle tick, or not. So, the challenge for this build is, if the military asked me what their current AR based combat rifle should look like, what would I come up with? Like many people here, I could think of twenty different ideas in ten minutes but, I need to come up with just one so, I would go with something like this.
Carbines are useful but, there is just something about a rifle that is hard to beat. Not that I would get rid of the M4, just keep it more for where and when a compact carbine is really needed and issue this as a general purpose, more reliable, harder hitting option. Of course we all know it’s not that simple and the world of military procurement is full of intrigue, politics, exotic women and other enticements so, I wouldn’t stand a chance. Even so, here is my idea.
Also, by using a S&W M&P15 receiver, I’m showing what their top of the line model could look like… if they dared.
Come on… I dare ya… go for it… 4150 barrel, HPT/MPI barrel & bolt and all.
The design is similar in some ways to a Mk 12 SPR except, instead of being a sniper rifle, the purpose of this is a combat / utility rifle, a bit more compact than a M16A2 and able to deliver more of a punch than a M4. The shorter 18" inch barrel and an A1 stock make it more maneuverable than a M16A2 without compromising performance and while larger than a M4, it’s 3.5" of extra barrel give an important speed boost to the velocity dependent 5.56 round. The barrel’s profile gives it an advantage over both.
Sorry S&W… Being able to build your own ARs means you can build a better M&P15 than Smith & Wesson.
I always start with the barrel and then integrate everything else around that. As the barrels is the heart of the gun, I’m picky about what one I chose and recently, I’ve been doing some further research in to the subject. So, the starting point for this build is a Sabre Defence 18" fluted MIL-B-11595E Chrome Moly Vanadium (CMV) steel HPT/MPI barrel with hard chrome lining, 1:7 twist and a mil-spec 5.56 NATO chamber. Mil-spec is the most misused term in the AR dictionary but, Sabre is one of the select few companies to ever be awarded a contract to build genuine mil-spec ARs for the DOD. Every Sabre barrel is subjected the same ISO quality control regimen used for their military contracts, with both scheduled and random inspections performed at all stages of the manufacturing process including multiple borescope inspections before and after chrome plating and during the rifling and chambering processes. All Sabre barrels are marked with lot numbers, tracing them to specific material certifications, machinists and even machines used. Also, because only a few gun manufacturers build weapons for the military, most don’t have ready access to the special alloys used. On an ongoing basis, Sabre purchase premium mil-spec barrel steel, MIL-B-11595E Chrome Moly Vanadium (CMV), in the only way it’s available, by the mill run in massive 93,000 pound quantities, that are then consumed to manufacture 5.56, 7.62 and .50 caliber barrels. All of this puts them in a unique position to deliver barrels with a level of quality the private sector rarely have access to, at economical prices most others can’t match.
Sabre employees merge cutting-edge technology with old fashioned craftsmanship in their barrel production area.
Sabre’s barrel production facility is a integration of the latest gizmos with tried and true machines.
This is a fairly unique approach and indicates people who really understand their craft.
Morris Blanton, Sabre’s quality manager, uses a Hawkeye borescope and video system to inspect a finished AR-15 barrel.
(picture courtesy of Modern Machine Shop)
Meticulously made from the best materials, this barrel starts almost exactly like a slightly shortened mil-spec M-16 barrel but, then it’s improved by keeping it the proper thickness and cutting fluting the whole length, except at the gas block, for lighter weight, with more rigidity and better cooling. Just like a heat sink used in electronics, the fluted barrel provides more surface area for cooling and also makes a barrel that is stronger for it’s weight than a similar round barrel. Being a medium contour barrel and thicker before the gas block instead of pencil thin like the government profile, not only makes it more rigid, with less whip and therefore, more accurate but, also able withstand more continuous firing. Even so, the flutes mean it is close to the same weight as the government profile.
This barrel has a mid length gas system which is a bit of a strange choice on Sabre’s part for two reasons. First, when compared to a rifle length system, going with a shorter mid-length gas system increases average operating pressure, increasing stress on the action.
Second, when the distance between the gas port and the end of the barrel increases, dwell time, or the time that gas is pushed into the action increases, over gassing the action and increasing stress. This 18" barrel with a mid-length system has 8.2 inches after the gas port as opposed to the standard M16 with a rifle gas system and 20" barrel, which has 6.8" and is generally considered about ideal.
However, I really like this barrel and it isn’t so problematic that it can’t be fixed, it just requires some fine tuning. So, I used a Wolff Extra Power Action Spring. By resisting the carrier’s rearward movement, the stronger buffer spring slows down the unlocking of the bolt. This has a similar effect to having a longer gas system, as pressure will have dropped further by the time the bolt does open, meaning it takes less force to extract the spent round from the chamber. Also, by the time extraction occurs, the bullet will have traveled further down the barrel, having a similar effect to reducing dwell time. Solving the issues with this barrel, the Wolff Extra Power Action Spring Reduces the forces on, and velocity of the action, reducing stress and recoil, and consequently increasing overall reliability.
The bolt and carrier are regular LMT. The carrier is M16 for the correct mass and the fact that if this were a military rifle it would be full-auto. The bolt is a proper shot peened 158 Carpenter steel, HPT/MPI checked unit and, for improved durability, has some of the stress relieving radius cuts, found on the special LMT bolt lugs.
The Vortex flash hider isn’t an absolute must over an A2. It is an A+ flash hider but, scores an F- for recoil control. On the other hand, how much recoil control do you need for what is essentially a full size 5.56 rifle? I experienced no problem keeping it on target for follow up shots as, since tuning with the correct recoil spring, the rifles’s recoil is mild.
Setting the new standard by being selected by SOCOM for the SOPMOD II program and by the UK MoD as well, the highly successful Daniel Defense M4A1 RIS II T6 aluminum handguard free floats the barrel, and also a M203 if attached, insuring an unstressed barrel for undisturbed accuracy. I have the similar Daniel Defense 7.62 Lite 12 rail on my AR-10 M110 type rifle and both rails use the same patented Bolt Up method of securing it to the rifle, which is extremely solid. The RIS II has the added advantage of a removable bottom making it simple to inspect the gas block and clean off the barrel. The one draw back is it requires you to buy a custom barrel wrench but, it is only $10.
The light weight ERGO RIBLOCK rail covers provide excellent grip and insulation. I really like the ribs and the solid, hand full feeling in your hand plus, they isolate you from the warmth radiating from the barrel, yet don’t block the air flow for cooling. Unlike many covers, they are easy to slide on and of with no risk of scratching the anodizing yet, stay firmly locked in place.
Similar to the VLTOR/BCM handles, the new Badger Ordnance Gen II tactical latch is well designed and a big improvement over the first generation. It gives you a firm grip with less chance of snagging and allows charging with either hand. While pricey, the Norgon mag release is a beautiful piece of engineering and craftsmanship. Having flexible, ambidextrous fire control, charging handle and magazine release are a benefit to any operator, left or right handed. (I already consider the bolt release to be ambidextrous as all you do is squeeze the top of the receiver with either hand and I’m not a big fan of clunky external levers like the B.A.D)
With the Aimpoint M2 - M68/CCO co-witnessed with the irons in the bottom third, it has fairly standard good quality red dot optics, which in this age should be the norm for every soldier’s rifle in combination with iron sights. You still need the iron sights for backup and long range shots but, the faster target acquisition and improved situational awareness of having a red dot with both eyes open are a real plus in the dynamic complexity of combat. The Aimpoint’s biggest drawback is, by it’s self, it is extremely difficult to figure holdover for distance. An ACOG would be a perfectly acceptable sight as well and solves the holdover problem without resorting to iron sights. On another rifle I have one of the new two dot EoTechs, which address the holdover problem well. However, I find an EoTech slightly better for rapid target acquisition and an Aimpoint better for precise aiming at a point. Maybe that is why it is called an Aimpoint?
I set up at 25 meters to sight the rifle in, first the irons and then the Aimpoint. To test both function and accuracy, I tried a wide selection of ammo including M-193 55gr. Guatemalan 55gr. and Prvi Partizan 62gr. & 75gr. JHP all with respectable results. Once I had everything dialed in I had no problem keeping every shot in the 1" center ring. I was shooting with the front of the rifle in the palm of my left hand supported by the pictured Remington rest and the back supported by my right hand and shoulder so, I wasn’t even using a fully supported front and rear shooting rest yet, was easily able at achieve these results. This target represents a typical grouping and with that, I’m looking forward to shooting at further distances and with some Black Hills 77gr. SMK ammo. I’m thinking my research into who is turning out quality barrels seem to have paid off and this rifle may be more capable of holding it’s own against a Mk12 than I thought. While at this distance it is too soon to reach any conclusions about ultimate accuracy, for the first time shooting a rifle, things don’t work out much better than this.
While not exactly camouflage, the flat dark earth color forearm, stock, pistol grip, magazine, optic cover and rail covers helps conceal the weapon by breaking up the all black exterior. Being a basic earth tone it blends in anywhere from the city to the jungle, integrating with both natural and man made backgrounds. It is a highly flexible color that will work just about anywhere with the possible exception of the North Pole or Antarctica.
- 18" Sabre Defence fluted MIL-B-11595E Chrome Moly Vanadium (CMV) steel HPT/MPI barrel with hard chrome lining 1:7 twist and 5.56 NATO chamber.
- JD Machine Low Profile Gas Block - 303 Stainless/Black Oxide Finnish
- Smith Enterprise G6A2 Vortex Flash Eliminator - 5.56
- Daniel Defense M4A1 RIS II Quad Rail Free Float Tube Handguard T6 aluminum Type II Hard Coat Anodized in SOCOM approved Flat Dark Earth w/ removable bottom
- LMT HPT/MPI bolt & LMT M16 carrier
- Badger Ordnance Tactical Latch Gen II on forged charging handle
- Wolff Precision Gunsprings, Extra Power Action Spring.
- YHM A3 upper receiver w/extended M4 feed ramps and “T” Markings, plated per MIL A-8625
- Spikes Tactical “Made in USA” w/flag dust cover (Reminder of who you are fighting for, in case of head trauma.)
- MaTech 600M rear sight
- MI H&K type hooded diopter folding front sight
- Aimpoint COMPM2 - M68/CCO 4 MOA red dot optic w/ kill flash and rubber protective cover
- Aimpoint QRP2 Picatinny Mount, Spacer and Ring.
- Smith & Wesson M&P15 Lower Receiver MIL A-8625 hard coat anodized
- Armalite lower parts kit (LPK w/o Trigger)
- LMT Tactical Two Stage trigger assembly
- Norgon left side magazine release
- Stag Arms ambidextrous fire selector
- Knights Armament Combat Trigger Guard
- ERGO Gapper trigger guard/receiver gap filler
- ERGO RIBLOCK FDE rail covers
- ERGO Suregrip FDE Pistol Grip
- Cavalry Arms FDE A1 Stock
- MagPul PMAG FDE 20rd. & 30rd. Magazines.
So, that is my take on what the current issue US military rifle should be like. Everything is mil-spec and ready to go off the shelf although, it is probably too nice a rifle to be considered standard issue. As a loyal supporter of my country and it’s military, they are welcome to use my idea for free but, at that price, I’m sorry, I can’t provide exotic women and bribes. Also, I do apologize, I don’t have the obligatory promo picture of me, in face paint, rising out of the water with the rifle. Because of that, they will totally ignore me but, at least I end up with a nice rifle to add to my collection. Oh yeah… if Smith and Wesson want to make this their new top of the line M&P15, that’s fine to but please, hook me up with a nice pile of AR parts to tinker with or an exotic woman or maybe both?
