The stock, and some of the bolt parts are simply Non-Parametric IGES Solids pulled from FirearmsFiles.com, but I've been creating my own parametric models based on them. Everything else - the barrel assembly and parts, gas tube, lower, upper, trigger, trigger guard, forearm, and most of the bolt carrier group have been created from scratch, from the drawings.
Oh yeah, and the railed forearm is also my design as well. It's just been superimposed on the barrel nut, I haven't actually figured out how I'm going to attach it just yet, if I'll be using it at all.
Here's the entire system. Shown here is the semiauto model only, with a semiauto bolt carrier group, although note that the trigger (which is an AR-15 trigger that I also modelled myself) has an notch cut in it for the full auto disconnector. I couldn't be assed to make different ones.
From the other side, minus the stock, gasblock, and impingement tube...
Closeup of the gas impingement system. When I sat back and looked at it presented in 3D from this section view, my first thoughts were "Wow, Eugene Stoner sure thought of everything." Look at the little gaskets around the bolt. Not only does the gas push the carrier group backward, but it also eases the bolt forward a tiny bit to aid with it unlocking. I never noticed that until now. Note that in this picture, the cam pin is out of position - I was fiddling with the assembly constraints when I made this, so it's not where it should be.
High Quality rendering of the AR-15 Lower Receiver, or at least the semiauto one.
Since every guy, his little brother, his grandma, and her dog are out making AR-15s, I've been thinking I might do something a bit different instead of just making another AR-15 type. So, what I'm going to be doing is following the same procedure that Magpul did when they created the Masada/ACR - I'll start with the basic AR-15 design, then slowly start trying to evolve whatever I like in and don't like out. So what I'm probably going to end up keeping would be the fire control group, some parts of the bolt and carrier, and a bit of the lower. The rest I'll probably do away with or evolve out.
So far, here's my little list of to-dos. As I was creating the model, I looked at different things and asked different people I knew about their opinions on how to go about it.
- Implementation of dual self-regulating 'shut off and expand,' short-stroke gas pistons with non-reciprocating inertial operating rods. If one operating rod breaks, its piston fouls, etc, the other will be able to carry its load with little if any change in cyclic rate. Additionally, the pistons and operating rod will not be attached to the barrel, so barrel changes can be made more easily. (more on that later)
- Hard Facing of the bolt face with Stellite No. 01 Alloy for increased wear resistance.
- Use of Carpenter No. 158 (AISI P6) Molding Steel for the Trigger, Sear, Disconnector, Selector Switch, (and AutoSear in full auto models), same material for the bolt, carrier, and carrier components. Additionally, these parts I've specified to be strengthened via shot peening and inspected by MPI, just like the military specifications for the M16 call for.
- Use of MIL-B-11595E instead of AISI 4140 for the barrel, like on real Mil-Spec rifles.
- Replacement of the standard charging handle with an ambidextrous non-reciprocating forward charging handle to allow for charging of the rifle without removing it from the shoulder that can double as a forward assist to help clear jams and allow the bolt to be lowered with less noise if desired.
- Chrome Plating of the Bolt Carrier and Group for increased reliability and wear resistance.
- Quick change barrel system involving an interrupted screw and foolproof 'positive lock' system similar to the FN MAG-58 "M240" with a button removal to avoid the barrel release catching or snagging with a fixed barrel extension to eliminate the need for manual headspacing, with an integrated carrying handle on the barrel that folds flat to allow for barrel changes in combat conditions without the need for an insulative heatmitt.
- Rounding of the bolt lugs and removal of the bolt face undercuts for a stronger and more reliable bolt.
- Fixed ejector to prevent the ejector from breaking and eliminate the problem of the ejector spring becoming tired due to excessive use.
- Repositioning of the buffer spring to be in line with the piston to prevent the bolt carrier group from tilting during operating cycles that plague most aftermarket AR-15 piston kits.
- Removal of the protruding recoil buffer tube to allow the use of folding stocks or bullpup configurations
- Ambidextrous controls for the magazine release, bolt catch release, both within easy reach by the index finger of either hand.
- STANAG-compatible magazines, or the use of SR-25 magazines for the H-models.
- Hardfacing of the Cam Pin Track with pressfitted Stellite No. 1 Alloy inserts to minimize wear during operating cycles and prolong receiver life.
- Hard Chroming and machine jewelling of the bolt ways to minimize wear, decrease coefficient of friction, increase reliability, and retain lubricating oils.
- Multiple position gas vent switch on the gas block, adjustible for different rates of fire or if the gas vent becomes clogged, or for use with silencers.
- Implementation of a tungsten-powder recoil buffer to minimize felt recoil while avoiding the leakage problems that plague most hydraulic recoil buffers.
- Removal of the 3-round burst system and implementation of a Safe-Semi-Full selector switch for Military/Law Enforcement/Private Security Consulting models only.
- Adjustible cheekpiece and length of comb on the stock.
- Furniture to be made of 35% Glass-filled Dupont Zytel
- Elimination of the gas key removes the need for the gas key screws to be 'staked,' which in turn eliminates the risk of the gas key breaking off or the screws fatiguing and coming apart.
- 7075-T6 Aluminium Forgings for the upper and lower, finished MIL-A-8625 Type III Hard Anodize with optional Cerakote available for other options such as Ranger Green or USSOCOM Flat Dark Earth. (This isn't really a design change, because that's Mil-Spec, but I figured I'd list it anyways just for reference.)
- Reversible upper capable of being made to eject from either side by replacing the bolt and replacement of some panelling.
- "Heavy Barrel Light Support Rifle" - "HBLSW" - models capable of transitioning from closed-bolt to open bolt configuration during semi automatic or full automatic fire (Military/Law Enforcement/Private Security Consulting models only).
- Maximum cost of $4000/unit or less.
- Monolithic STANAG-4694 compatible rail on upper reciever, and at 3 o'clock, 6 o'clock, and 9 o'clock positions on fore-end to replace the older M1913 standard yet remain backwards compatible with M1913-compatible accessories.
- Additional bolts to allow for chamberings in 5.56x45mm, 6.8mm SPC, and 6.5mm Grendel for the L models. The H model will probably be 7.62x51mm only for now.
Tell me what you think! I'm calling my creation the "D13-N0W" or just the "D13." I'd thought of other designations such as "FU-411" or "1-K1LL-U" but then realized that nobody'd take it seriously if I called it something along those lines. I'm hoping to get into the civilian and private security consulting industry, because as much as the military appeals to me, I doubt they're going to shift away from the M16/C7/M4/C8 anytime soon.