Airsoft has changed dramatically in recent years. “Back in the day,” when I bought my first S-AEG a little over five years ago, the hobby was characterized by DIY solutions, unreliable parts, and constant tinkering.
Today? Anyone familiar with the subject who does a little research can build an absolutely reliable, ready-to-play system for a reasonable price—without compromising on quality or performance.
My current AR-15 project illustrates this point perfectly: a build that is no longer “better,” but simply “finished.” And perhaps that is precisely the definition of peak airsoft—the moment when the product is so mature that there is little room for improvement.
That’s why I think this could be my last AR-15 build. And that’s a good thing.
Note:
The Arcturus M4 Hybrid MUR MOD C SBR presented here was kindly provided to me by Begadi at a discount. However, this does not influence my honest and independent opinion of the product in any way. I am writing this article as if I had paid the full price – and am evaluating the weapon solely based on my personal experiences and requirements.
Transparency note:
Some of the links in this article are affiliate links. If you buy something through one of these links, I’ll get a small commission—at no extra cost to you. This supports my work and helps me keep writing detailed and time-consuming articles like this. You’ll find a complete list of parts with all the links at the very end of this post. Thanks a lot!
🧱 The basis: lots of technology, low price
The basis for this build is the Arcturus M4 Hybrid MUR MOD C SBR – Begadi Upgrade Version. Even without the team discount, this system offers features that would have cost significantly more just a few years ago – if you could even find comparable components at all – for just €309 ex works.
As a reminder, my very first S-AEG, the G&G MPW 7″, died immediately when I attached a 30C battery, as this was too much for the electronics and my MOSFET burned out.
And that wasn’t 10 years ago, but only 5. So you had to figure out how much peak power the electronics could handle and choose the right battery. That’s much easier now, and beginners can’t really go wrong.
Back to the Arcturus M4 Hybrid MUR MUD C SBR!
Even in its basic configuration, the weapon offers:
- A Mamaba 19K Super High Torque Motor that is powerful enough for fast cycles, yet energy-efficient and power-saving – ideal for compact LiPo batteries and long days of play.
- The Begadi CORE EFCS/Mosfet, an electronic control system that not only reliably completes the gearbox cycle, but also offers features such as integrated battery monitoring. This protects the battery and prevents deep discharge, as the system switches off in good time.
- A 6.01 mm stainless steel precision barrel, which ensures high airtightness due to its narrow diameter and is particularly durable thanks to its robust material. Brass or aluminum barrels are significantly softer and scratch more easily. This in turn can lead to inaccurate shooting patterns.
- A Begadi PRO FLY5 HopUp Bucking in a good HopUp unit, which performs very well right out of the box, is precisely adjustable, and ensures clean BB feeding.
- A high-quality polymer body that not only saves weight but is also shock-resistant—and significantly lighter than comparable metal bodies.
This base immediately won me over. Not only because of the price, but also because it is practically ready to play – not a “work in progress,” but a reliable platform.
Begadi offers the upgrade version, which differs from the standard Arcturus offered in other markets in the following ways:
- Begadi CORE EFCS/Mosfet
- Mamba 19K Super High Torque Motor with Neodymium Magnets
- Begadi PRO Pistonhead with Double O/Quad Ring
- PRO HopUp (FLY5 60° + 5mm Tensioner)
🛠️ Modifications: From “solid foundation” to “just my thing”
Of course, no build remains completely untouched by me. But unlike in the past, when you often had to replace parts, today it’s more about fine-tuning, customization, and personal preferences. And to be honest, I assembled this build from parts I still had lying around in my airsoft junk box. So I didn’t even have to buy any additional parts.
My goal was to build a lightweight, powerful, and low-maintenance system that can hold its own on any playing field. No gimmicks, no unnecessary aesthetics—just a handy tool that works.
Die wichtigsten Anpassungen an meiner Arcturus MUR MOD C
- Stock: APS RS3
Compact, functional, and visually appealing—offers good shoulder stability and a clean look. - Grip: PTS EPG
The most ergonomic grip I have tested so far. The standard grip is good, but I have large hands and the PTS grip feels much better. Like SandGrips, it offers a firm grip, even when wearing gloves or in the rain.
- Foretgrip: BCM M-Lok Grid
Extremely light, flat, and grippy. Ideal for aggressive play and quick grips. - Rail Cover: Magpul M-Lok Rail Cover Type 1
A small but extremely effective detail: I have mounted Magpul M-Lok Rail Cover Type 1 on both sides of the handguard. These rubber strips are narrow, flexible, and provide a consistently grippy, pleasantly soft feel at the front. Especially during longer matches or when you’re using the C-grip a lot, this makes a real difference in handling—less fatigue, more control. Again, it’s all about the principle: no frills, just targeted improvements for real practical benefits.
- Optic: Sig Romeo 5 with 1,93″ Riser Mount
Reliable red dot with motion sensor, ideal for quick target acquisition. The high riser is particularly valuable in combination with masks such as the DYE i5 Gold – you can see through the optics without having to turn your head. - Dummy DBAL-A2 Box
Purely aesthetic – but if you want to give your AR-15 build a polished look, there’s no getting around this element today. And so the wireless switch also has a function, at least visually, on the weapon.
- Wireless Switch for the 1.000 Lumen Lamp on my DYE i5 Maske
Since weapon lights on airsoft guns are prohibited in Germany, I have relocated the light. Using a wireless switch on the handguard, I can activate my external light on the mask—a clever solution for temporary lighting without breaking the law.
- SandGrips by Copper and Brass – that’s me, hi! 🙂
Textured grip stickers made of aluminum oxide that significantly improve grip on the handle. Small, inexpensive, durable, and highly effective. The SandGrips shown in the pictures have been stuck to the handle for two years and are still holding strong. - G&G Midcap Magazine (The picture shows the Real-Cap magazine)
For this build, I only use G&G mid-cap magazines, specifically the “G&G M4 / M16 Competition Polycarbonate Magazine” with 105 rounds. The big advantage: the transparent shell allows you to see at a glance how much ammunition is left – no need to change magazines or guess. What’s more, the magazines work reliably, don’t make that annoying rattling sound like high-caps, and feel high-quality – perfect for my needs.
- HopUp Bucking: Quantum Friction Pro
This component makes a real difference for me. The bucking provides perfect sealing, even pressure across the tensioner, and a stable shot pattern. In combination with the stainless steel inner barrel, I achieve deviations of less than 0.2 m/s in muzzle velocity—that’s almost HPA level.
- Tracer-Unit: Performance meets recognition
At the end of the 14mm CCW barrel is an Acetech Blaster C Tracer, which I use in the blue version typical of Copper and Brass – on the one hand as a visual trademark, and on the other hand for functional gaming fun in indoor or low-light games. The tracer perfectly complements the build visually. For more “serious,” less “casual” events (e.g., MilSim, training, or outdoor games), I switch to a plain black tracer to keep the appearance more subtle.
An overview of what is likely to be the last Copper and Brass AR-15 project
With all the parts assembled, my Arcturus now looks like this:
🔋 S-AEG = LiPo = lightweight, efficient, practical
I use a Begadi AMAX 1,200 mAh LiPo battery. It fits perfectly into the system, or more precisely into the buffer tube, weighs very little, and—thanks to the efficient Mamba motor—easily lasts for an entire day of play. Even with a high rate of fire and active play, I don’t have to change the battery in between.
The entire S-AEG weighs only 2.7 kg. This is a huge advantage, especially for players who are constantly on the move, often take aim, or play longer matches with endurance.
I’ve never been a fan of heavier builds – because at some point, you just notice it. This setup allows me to play quickly, responsively, and with endurance, without compromising on stability or precision. But hey, I also have breathable foam pads in my plate carrier. To each their own 😉
🚫 “But why don’t you play an HPA system? 🫨”
HPA is often hailed as “the next big thing” in airsoft. But for me personally, the disadvantages outweigh the advantages – despite all the technical benefits:
- Cost:
A complete HPA kit can easily cost several hundred dollars—for the tank, regulator, adapter, and hoses. For me, the price is disproportionate to the additional performance offered. No one (outside the Speedsoft community) can tell me that they can fire 10 shots per second or that their system is more accurate or offers noticeably less variation. - No hoses = freedom of movement:
For me, the hose is a real fun killer. I even carry the S-AEG without a sling, which means I’m not restricted in my movements, especially when I take cover or change position. I feel that my game flow suffers noticeably from designs such as slings and, therefore, hoses. - Safety concerns:
Running across playing fields with potential trip hazards while carrying a pressure cylinder on my back just doesn’t feel right to me. Even if the danger is objectively low, I don’t want to carry it and possibly fall unhappily on a cylinder that would give way by 0.0 mm. - Maintenance & complexity:
For me, S-AEGs are the epitome of “just works.” Insert the battery, load the BBs, go. If there are any problems, I know every screw, every cable, and every gear. With HPA, you rely on significantly more external technology—that doesn’t suit my style.
The technology of my S-AEG is now so consistent that I don’t miss the potential advantages of HPA. I play easily, efficiently, and reliably—without any bottles, regulators, or hoses.
📈 So, have we reached peak airsoft? What now?
Five years ago, a setup like this was still an ambitious project for players and technicians who really knew their stuff. Parts such as ETU+Mosfets, 6.01 mm precision barrels with matching buckings and tensioners in a well-feeding HopUp unit, or good motors had to be laboriously researched, ordered, and, if necessary, adjusted. That’s if they were even compatible with each other to the extent required.
Today? All of this is standard and can be further optimized in just a few simple steps. Anyone who can replace a HopUp Bucking and knows how to zero in a red dot sight has virtually no work left to do when building their “technically clean” S-AEG. For a fair price, you get technology that used to be “high-end.”
This reminds me a lot of the development of smartphones: revolutionary at first, then rapidly optimized – and at some point… just “better.” But not much better. The innovations are getting smaller, the differences finer – but the actual added value? Marginal.
That’s exactly where airsoft is now. We are at a technical level that no longer needs any major leaps forward. Above all, affordable builds like this one simply work. And that’s great!
✅ My conclusion: Satisfied instead of restless
For me, this build is the product of years of experience and development. I know what works for me and, above all, what I need—and what I don’t need. Begadi understands how S-AEGs work perfectly and what customers want.
The result is an S-AEG without excessive features or gimmicks. Just what works reliably and has proven itself in the game.
Maybe this really is my last AR-15 project. Not out of frustration, but because there’s nothing left that I want to improve. Everything is as it should be.
And that’s a rare feeling in a hobby that often thrives on constant change.
Open 4K wallpaper for this build in a new tab
🛒 Complete parts list for this build
🔧 Airsoft Gun as basis
🛠️ External attachments & appearance
- APS RS3 Stock
- PTS EPG Griff
- BCM M-Lok Frontgriff (save something with the code copperandbrass)
- Magpul M-Lok Rail Cover Type 1 (save something with the code copperandbrass)
- Sig Sauer Romeo 5 Red Dot
- 1,93″ Riser Mount
- DBAL-A2 Dummy Box
- Wireless Light Switch RSW2i WL (discontinued)
- Nitecore P10i (DYE i5 Maske mounted)
- Acetech Blaster C Tracer (Copper and Brass blue / sometimes black)
