The M16/M4 series of guns is without a doubt the most popular type of airsoft gun in the US. As a result, it isn't hard to find a lot of different variations of the gun at any game. Having seen many of the variations and customizations of the M16/M4 series out there, I wanted something that was not limited to commonly available, bolt-on airsoft parts. After searching for all the real steel AR variants I could find, I decided that none of them really had the overall look I wanted. Since I couldn't find a gun to use for reference, I started with a clean slate and came up with my own design.

The basic concept I had in mind was something closer to the civilian target rifle style than a military rifle. Civilian rifles tend to be a bit more unique in terms of cosmetics due to the fact that they do not have the same modularity requirements and restrictions as a military rifle. Being able to comb through web sites and catalogs to pick and choose each part to assemble a unique rifle allows more freedom and produces more variety. I wanted something unique that no one else would be able to put together.

	For the body, I chose the DTP SR-15 body. The main reason is that it has a more geometric look, which I find more appealing than the conventional M4 type body. The main drawback to the DTP body is its weight. Since the body is cast zinc with very thick walls (to give it strength since zinc is softer than aluminum), the body ends up being almost 4 times heavier than the Systema style metal bodies. In addition to its weight problem, the DTP body is also cast a bit oversize in some areas like the magazine well, which requires a bit of filing and fitting to make sure everything operates correctly.
The first piece to be fitted to the body was the ACE Ltd. ARFX stock. This is a skeleton style stock that uses the real steel AR15 buffer tube for the upper arm and aluminum tubing for the lower arm. The end plate that connects the two arms is drilled and tapped to allow the use of a rubber or plastic butt pad. The front piece has been drilled and tapped to allow sling swivels/attachments to be screwed on. The aluminum parts are hard anodized in matte black. Once assembled, the ARFX stock is solid, yet lighter than the Marui M16A2 solid stock.

Fitting a real steel AR15 stock to a Marui based body is pretty easy now since G&P makes their real stock adapters. The hardest part is cutting the threads on the buffer tube to make it flush with the receiver. However, at the time I was working on this gun, G&P hadn't yet released these adapters. This meant I had to make my own adapter.
The adapter I made is a section of aluminum tubing cut to fit over the normal stock mounting stub on the lower receiver. The outside of the tubing is cut to allow the AR15 buffer tube to fit over it. The ARFX stock then slides on and the Marui long stock screw can be used to secure the stock to the body.

Since I knew I would be using a battery bag with this setup, I had to find a way to route the wires out the back of the gun. My solution was to use a metal stock ring as a spacer and cut it to allow the wires to exit the body. This way, I didn't have to cut the body and/or stock. So if I re-route the wires later, I can just remove the stock ring and not have to cover up any cuts.

With the body and stock taken care of, the handguard assembly was next. One thing I never really liked about all the M4 variants I've seen is that they all look generic. Either they use the stock handguards or they have rails covering every surface. While I'm sure that's the "authentic" look for a military M4, I really prefer the styling of the target and competition AR15's. Since I knew I would never mount anything on the handguard, I was free to focus on creating something unique.

The idea I came up with was to create an outer handguard that would fit over a typical 2" diameter free floating handguard. Visually, it would create a larger, more open setup to allow more of the barrel to show. For stability, everything would need to be bolted together, so an extended ARMS #38 rail would be used to connect the handguard assembly to the receiver for support.

The inner handguard is a DPMS carbine length free floating handguard. After checking out a few different handguards, I selected this one because it's simple design seemed to blend well with the other parts.
To fit the real steel handguard to the DTP body, the receiver threads were re-cut to the specs of a standard AR15 receiver. Having the right threads on the receiver makes it a lot easier to secure the handguard.

Starting with raw 2.5" diameter, 1/4" thick round aluminum tubing, the outer handguard was milled from a single piece. The outside was squared off and the corners were cut with rounded grooves along the length. The front and back faces were cut at angles to match the grooves cut into the side of the handguard.

Attaching the ARMS #36 rail to the upper receiver required a bit of filing since the top rail on the DTP body was oversize. Not really a big deal, and it actually makes for a more secure fit since there is no play or wobble in the rail. To connect the top of the outer handguard to the ARMS rail, a custom bracket was added. From there, everything was bolted together. The end result is a VERY solid handguard assembly with no wobble. The outer handguard, bracket and ARMS rail were all bead blasted and hard anodized in black to match the look of the rest of the gun.

For the outer barrel assembly, I wanted something similar to the heavier barrels used on target rifles. To do this, I cut down a First Factory APS2 Aero outer barrel. The front was cut to remove the rings and I made a new end cap for it. Set screws hold the end cap in place and also secure the end of the inner barrel. Yes, the set screws do show, but I'm willing to make that cosmetic sacrifice for better accuracy. After all, this is a gun to be used, not displayed. The outer barrel and end cap were nickel plated and then heat treated. The heat treating adds strength to the nickel and gives it a slightly darker finish.
A real steel GB gas block and gas tube complete the outer barrel assembly.

The sight I chose is a Tasco 35mm PDP3. While a scope would seem to be the more fitting choice in terms of cosmetics, a red dot sight is much more practical for gaming use. At least, it is for me. Given the typical engagement distances in airsoft and the faster target acquisition with a red dot, it works pretty well for the way I play.

As a long time fan of H&K rifles, I really prefer the feel of the G3/MP5 style "eurogrip" over the traditional M16 pistol grip. The Zenith TAC Grip offers a feel similar to the H&K grip, so that's the one I picked for this rifle. Installing this grip on the DTP body required a bit of fitting due to the odd dimensions of the body. Out of the box, the Zenith grip sat about 1/8" out from the body. Cosmetically, the gap allowed the mechbox to show. Mechanically, the holes for the motor shaft didn't line up, so the motor would bind. After a lot of filing and trimming, the Zenith grip sits flush with the body and mechbox, solving both the cosmetic and mechanical issues.
The trigger guard is KM's Sniper trigger guard. It's the first version with just one bend towards the rear, right below the trigger. The charging handle is the G&P SPR type. The G&P charging handle has a better finish than the Systema part and it features a larger t-handle as well as a replica of the PRI Big Latch.

This rifle is without a doubt the most labor intensive airsoft gun I have built so far. It's also one of the longest projects I've ever worked on, taking up a good amount of my free time through all of 2003. But the results are definitely worth it.

Type: AEG
Gun Dimensions:
  Length: 953 mm
  Height: 250 mm
  Weight: 4.53 kg
Muzzle Velocity: 390-395fps with Excel .20's