ST Kinetics BR18: the ultimate bull-pup assault rifle?
GUNSweek.com was granted exclusive access to a production sample of the ST Kinetics BR18 assault rifle from Singapore: has it the potential to become the ultimate embodiment of the bull-pup assault rifle concept?
Singapore Technologies Engineering Ltd. – or ST Engineering for short – may not be a household name for the vast majority of the general public, but experts and professionals in the defense business are definitely familiar with it. Headquartered in the Republic of Singapore, ST Engineering is a global leader in aerospace, electronics, defense systems.
Within the Singapore Technologies Engineering company, Singapore Technologies Kinetics (ST Kinetics or STK for short) is the Land Systems division tasked with the development and manufacturing of weapon and ammunition systems, known for famous small arms such as the ULTIMAX-100 light machinegun, engineered by L. James Sullivan, as well as the CPW Compact Personal Weapon and the SAR-21 assault rifle. ST Kinetics small arms designs are time-tested and combat-proven and known for being sound and innovative.
That is also the case with their latest small arms development, to which we at GUNSweek.com were granted exclusive access thanks to ST Engineering and their official distributor for the United States – Phoenix Defence, headquartered in Henderson, Nevada.
We are talking about the ST Kinetics BR18 bull-pup assault rifle.
ST Kinetics BR18 bull-pup assault rifle - right side
ST Kinetics BR18 bull-pup assault rifle - left side
The development of the ST Kinetics BR18 was initially unveiled in 2014, when a prototype dubbed the BMCR (Bull-pup Multirole Combat Rifle) was showcased at the Eurosatory expo in Paris; the project was finalized in 2018.
The BR18 was developed to replace the SAR-21 as the standard service weapon for the Armed Forces of the Republic of Singapore as well as for export, and through its development, ST Engineering focused on solving some of the inherent flaws and drawbacks of the bull-pup design.
A new generation bull-pup rifle, the BR18 is chambered in 5.56×45mm NATO and was conceived from the ground up to be ambidextrous and as lightweight and short as it can be, in order to fulfill all roles in all specialties of an Armed Force – infantry, mechanized troops, paratroopers, Special Forces – without significant modifications.
From the point of view of Singapore – which, being a city-State, would witness mostly urban warfare if engaged in a defensive conflict – this is a significant advantage; export-wise, the design features of the BR18 make it quite a tempting procurement alternative for many customers.
The BR18 design underwent several significant simplifications if compared with the BMCR prototype, which sported a lower polymer receiver and an upper metal receiver. On the BR18, both receivers are chiefly made of latest-generation composites, with metal reinforcements where needed and special attention paid on the selection of composite materials and formulas to provide resistance to heat, abuse, and harsh conditions. This allows the BR18 assault rifle to reach a maximum weight of four kilograms (8.8 pounds), depending from the variant.
The one you see in the pictures illustrating this article is the baseline BR18 AR assault rifle, which is 64 cm / 25” long overall, sporting a 14.5” barrel, for an overall weight of just 2,9 kg– about 6.3 lbs.
The BR18 Sharpshooter Rifle, equipped with a 20" barrel, tops an overall length of approximately 80 cm (just short of 30") for an overall weight of 3,2 kg - about 7 lbs.
The heavyweight version of the design, with a weight of 4 kg (8.8 lbs) when empty, is the BR18 MGR “Machine Gun Rifle” variant, conceived to fulfill the role of an infantry automatic rifle, bridging the gap between the individual assault rifle and the squad support weapon; as such it is conceived to employ very high-capacity magazines and comes equipped with a heavy-contour 18” barrel and extra features to better withstand and dissipate the high levels of heat generated by sustained fire.
The BR18-MGR (Machine Gun Rifle) version of the design, featuring a heavy-profile 18-inch barrel for sustained support fire
The BR18-AR (Automatic Rifle) is lighter and simpler than the BMCR prototype, making it easier and less expensive to manufacture on a large scale
The upper receiver of the BR18 assault rifle, featuring the ambidextrous charging handles
The barrel of the BR18 is entirely contained in the upper receiver, with metal inserts where extra resistance is required
All the barrels manufactured for the BR18 weapon system feature a birdcage-style flash hider and six right-handed grooves with a 1:7” twist rate, which according to ST Engineering allows the BR18 to properly stabilize the 5.56×45mm NATO SS109 ammunition up to a maximum effective range of 800 meters (approximately 875 yards).
Barrels are contained in the upper receiver, which is connected to the lower by a single passing pin, allowing quick and tool-less configuration change in seconds, even in field conditions.
The carbon-fiber cheekpiece of the BR18 can be opened to provide access to the chamber (see photo at side), with enough room for direct intervention by the operator should troubleshooting be required
The BR18 is a closed-bolt, gas-operated, long-stroke piston driven system, with a gas valve located on the left side of the barrel, at exactly 90 degrees; it features a long, but captive, rod to allow easy adjustment for use with different types of ammunition or with silencers, or its removal for cleaning and maintenance.
The long-stroke piston is part of the bolt assembly and runs into a channel parallel to the barrel, somewhat reminiscent of the Steyr AUG system.
The fully self-contained bolt group can be extracted from the upper receiver as a single unit when the BR18 is field-stripped: no small but essential components to lose here.
The BR18 field-strips by removing a single passing pin located just over the magazine well; this allows the two receivers to be separated and then the bolt assembly and the carbon-fiber cheekpiece to be independently removed.
The lower receiver features an ergonomic, slip-proof pistol grip and a forward MIL-STD 1913 Picatinny rail for tactical accessories or grenade launchers; ST Engineering manufactures the STK-40GL MK1 40x46mm SR compact grenade launcher as an ancillary to the BR18, but it can be attached to any long gun with a Picatinny interface system or to its own proprietary stock to be used as a stand-alone weapon.
The lower receiver also hosts the entire trigger group, sear and hammer within a reinforced insert. All controls and the magazine well are also hosted on the lower.
The trigger of the BR18 assault rifle weighs approximately 3,5 kilograms, or 7.7 lbs; not terrible for a bull-pup, definitely lighter than the Steyr AUG or the IWI Tavor and X95 trigger. The trigger guard can be extended to allow comfortable handling when wearing gloves.
The controls are located just over the pistol grip area: the front switch, to be activated by the shooter’s index, is the fire selector, with a safety position, and semi-automatic and full-automatic positions; the cyclic rate in full-automatic for the BR18 ranges between 650 and 850 rounds per minute.
The rear switch, to be activated by the shooter’s thumb, is the magazine release catch; it is very reactive, easy to use, and magazines fall free.
The BR18 feeds through the same translucent plastic thirty rounds magazines of the SAR-21 rifle, or through most STANAG 4179 compliant “AR-15 type” magazines, thus making it compatible with the magazines used by most NATO forces. We say “most” because as we handled the gun, we found out that using MagPul magazines on the BR18 would be close to impossible due to the ribs in the bodies of these magazines that make them very difficult to insert and remove.
Behind the magazine well is a button – pretty much Tavor-style – that dubs as a bolt stop release, allowing the operator to slam the bolt shut and load a new round in chamber with his or her thumb once a new magazine is slabbed in.
The BR18 seen from under, with its minimalist and thin lines, and a top view of the inside of the lower receiver, hosting the full trigger group
The upper receiver features numerous ventilation ports and a full length top Picatinny rail for optics or backup flip-up sights – none is provided from factory – as well as an ambidextrous charging handle that pushes the bolt back through a curved interface on the top of the bolt group.
And the bolt assembly itself – which can be removed from the rear of the upper receiver upon field-strip – actually includes the vast majority of the metal parts found on the BR18. Its location provides good balance, allowing the BR18 to be used effectively off-hand in case of need.
The rotating bolt head features two prominent locking lugs. At its left is the long-stroke piston system, while on its right is a small plunger that’s the key for the BR18’s ambidextrous operation.
As a matter of fact, as the bolt cycles back after firing a round, the spent case is normally extracted and ejected to the right – but there is no ejection window proper there.
The case is instead deposited in a chute, machined on the right side of the upper receiver and featuring a prominent front deflector; when the bolt cycles forward, the plunger pushes the spent case out with force, forwards and right-wards, about at the height of the shooter’s right hand but far and away from him. This allows the rifle to be used by left-handed or right-handed shooters alike right out of the box.
The ST Engineering BR18 is not the first forward ejecting bull-pup rifle to make it to the market, but unlike the mainstream designs currently dominating this segment – more specifically the Kel-Tec RFB semi-automatic rifle from the US and the Belgian-made FN F2000 assault rifle – the forward ejection system of the BR18 does not have spent cases stacked one after another in a long chute and then pushed out as others pile up inside.
Download the official brochure of the ST Kinetics BR18 Assault Rifle
In fact, while effective in conventional shooting positions, said system can fail and jam the gun if it is fired upwards – and when engineering a firearm for urban combat, this must be taken into account.
Another major drawback of other forward-ejecting bull-pup rifles is that they do not allow the shooter to access the chamber directly without removing the magazine – or when they do, they do not provide enough space for troubleshooting.
The BR18 addresses this issue thanks to the peculiar design of the spring-loaded carbon-fiber cheekpiece, held in a closed position by a latch secured to the rear of the top Picatinny rail. When the latch is released, the cheekpiece slams open to the back, providing direct access to the chamber with room to spare for the operator to use tools or bare hands to solve any jam or other issues.
Overall simple and intuitive to use, the ST Engineering BR18 was conceived to be relatively simple – and thus cheaper – to manufacture on a large scale, while at the same time integrating the latest developments in terms of technology, ergonomics and handling techniques in a very handy and lightweight weapon system. If there is a firearm, as of today, that has the potential to change the minds of the many operators who still have their reservations on bull-pup rifles, that’s the BR18.
Furthermore, its features allow the BR18 to satisfy many of the needs of law enforcement agencies and special units in terms of small arms for counter-terror operations, hostage rescue, and other sensitive duties.
A close-up of the gas valve: a long captive pin allows easy regulation or removal for cleaning and maintenance, even when wearing gloves
Rear view of the upper receiver. On top is the seat of the contact point between the bolt group and the ambidextrous charging handle; on the bottom, from left to right, are respectively the gas piston seat; the chamber; and the forward chute for spent cases
A full frontal of the bolt group, with all its key components in sight – including the plunger that drives spent cases one by one off the forward chute
If there is a drawback to the BR18, is that the current location of sling attachment points – in front of the upper receiver and on the buttstock – may not be optimal for all sling designs and more modern tactical handling techniques. An ambidextrous quick-detach cup behind the pistol grip area would most likely be highly appreciated.
Civilian gun enthusiasts worldwide will NOT be pleased to know that ST Kinetics does not make firearms for the commercial market, and that as such, no civilian-grade version of the BR18 design is planned. This, unless the company decides to license off the design for global civilian sales to a third entity, but as of today, that’s still a pie in the sky.
ST Kinetics BR18 – Specifications
BR18
Bull-pup assault rifle
5,56×45mm NATO
Select fire, closed bolt, gas-operated, long-stroke piston driven
Single-action, single-stage, hammer-fired
Manual (safety position on fire selector)
30 rounds in SAR-21 translucent polymer magazines
Compatible with STANAG 4179 compliant magazines ("M16 style")
650 – 850 rounds per minute
- 36,83 cm / 14.5” (BR18 AR)
- 45,72 cm / 18” (BR18 MGR)
- 50,8 cm / 20” (BR18 Sharpshooter Rifle)
6 grooves, RH, 1 turn in 7”, Birdcage-type flash hider
No factory-issued sights – MIL-STD 1913 Picatinny rails built-in for accessories and optics
- 64,5 cm / 25.39” (BR18 AR)
- 78,5 cm / 30.9” (BR18 MGR and BR18 Sharpshooter Rifle)
- 2,9 kg / 6.39 lbs (BR18 AR)
- 4 kg / 8.81 lbs (BR18 MGR)
- 3,2 kg / 7 lbs (BR18 Sharpshooter Rifle)
Steel barrel, steel and alloy bolt group, black polymer receivers with metal inserts, carbon fiber cheekpiece
We thank Singapore Technologies Engineering Ltd. and Phoenix Defense for providing the firearm used for this review.