Sunday, February 16, 2014

A look at the world's shortest bullpup rifle: The Singapore Technologies Kinetics BMCR

Singapore's defence industry unveiled two new 5.56mm combat rifles at this week's Singapore Airshow 2014, including a weapon billed as the "shortest bullpup design in the world" (above, left).

Developed by the weapons labs of Singapore Technologies Kinetics (STK), the bullpup rifle bears a superficial resemblance to STK's SAR-21 5.56mm assault rifle. However, the firing mechanism and front ejection for spent cartridges suggests that the SAR-21 - the standard infantry weapon fielded by the Singapore Armed Forces (SAF) - underwent a major engineering redesign to transform it into the new weapon.

An STK statement said:"Giving infantry soldiers maximum lethality in urban operations, ST Kinetics’ new combat rifles are designed for compactness, minimum weight and full ambidextrous operations in a highly configurable multirole package.

"The STK BMCR (Bullpup Multirole Combat Rifle) and STK CMCR (Conventional Multirole Combat Rifle) possess multirole flexibility for assault, marksman/sharpshooter and suppressive roles, putting the infantry section ahead in lethality and in achieving their mission objectives. Both rifles are designed to fire NATO SS109 5.56mm ammunition and ST Kinetics’ Extended Range 5.56mm ammunition, and come standard with MIL-STD-1913 Picatinny Rails at the three, six, nine and 12 o’clock positions. 

"The STK BMCR is designed to be the shortest bullpup-design in the world, to afford easy handling by the soldier even in tight spaces. The STK CMCR, meanwhile, is designed with a unique buttstock design that allows the rifle to be folded and adjusted for maximum compactness during use."

The standard SAR-21 measures 805mm in length while the cutdown SAR-21 Modular Mounting System is a more compact 680mm from muzzle to butt. STK literature did not reveal vital statistics for  the BMCR, apart from the unsubstantiated claim that the rifle is the shortest bullpup design in the world.

A major omission on the part of this blog was leaving the tape measure at home. At past shows, measurements done in situ have tended to elicit strange looks from duty personnel and generate conspiratorial whispers. So we decided to behave like normal air show guests and the end result is a half-baked report like this one which leaves us unable to provide greater clarity to ST'K's  news release.[Fear not. At the next show/SAF open house, out comes the measuring tape, vernier callipers etc]

What we can show - thanks to obliging STK duty personnel - is the odd strange finger trap different arrangement to check the BMCR's chamber vis-à-vis the SAR-21 (see below). A catch on the left side of the butt stock is depressed to slide a cover plate back towards the firer. This reveals the rifle bolt and firing mechanism contained within. The gap is somewhat larger than the one on the SAR-21 which the firer checks to ensure the chamber is clear of cartridges. One wonders if this design feature, which resembles the sliding plate on old sewing machines, may end up as a dirt trap should the firer need to slide open the cover plate in the field.

Cover plate slides back to reveal firing mechanism

Forward ejection port

The BMCR ejects spent casings from the right hand side of the weapon. No deflector is needed for left-handed users as the trajectory of the cartridges traces a downward arc to the front aspect of the rifle, which means hot bullet casings are flung well clear of the firer's face.

The BMCR is designed to be fully ambidextrous, with firing selectors on both sides of the weapon and a magazine catch that provides easy accessibility to both left and right-handed users.

Senang Diri understands that forward ejection was preferred over downward ejection (as in the P90) to minimise the fall risk posed by empty cartridges littering the area around the firer's feet during urban firefights.

A possible downside seen from the ops side of the house is the possibility that the firer's position may be betrayed during urban ops by the stream of shiny bullet casings flying out of a window. It is understood that a bag to catch spent cartridge casings can be added to the BMCR to mitigate such risks.

Details on the CMCR are sparse. The weapon on show at SA 2014 was a non-firing 1:1 scale concept model.


Anonymous said...

May I suggest bringing a karang guni sliding scale too :D

Anonymous said...

i think the Tavor by Israeli Military is still smaller leh.

kilroy said...

hi David

they did provide these specifications:

Specification: AR/MR/MGR/MR-GL
Overall length: 649/789/789/789
Barrel length: 14.5"/20"/20"/20"

if I remember correctly, with a length of 745 mm, China's QBZ-95 is currently the shortest bullpup rifle. If this is the case, then it is possible that this new BMCR would unseat QBZ-95 and become the shortest bullpup rifle.

Anonymous said...

Tavor would be shorter overall and have half inch longer barrel.

Anonymous said...

I'm surprised the STK or AETOS personnel manning the booth didn't shoot you dirty looks.

Chatting with a few more amiable STK folks suggest that this is supposedly an adaptive system like the Bushmaster ACR (ex-Magpul Masada). Instead of the much vaunted fixed 1.5x scope, they have gone for COTS systems like that EoTech holo-sight.

That huge trigger guard on the CMCR? Probably for arctic/cold weather conditions when thick gloves are worn. Low temperatures are still supposedly the Achilles heel of our local small arms designs.

Anonymous said...

The all important weight of the rifles left out ?

I am not a fan of the SAR21.
Very heavy, no rails, poor 1.5X sight & lousy ergonomics.

SAF shud have just bought off the shelf.

Anonymous said...

@Anon 11:00am: Quoted weight for the BMCR is 2.9kg, about 900g(?) lighter than the vanilla SAR-21. Of course we'll have to see if it can be done in production variants.

Anonymous said...

You just have to be white, then the STK or AETOS won't shoot you dirty looks. Will give you a long technical explanation too.

David Boey said...

Dear Kilroy,
Thank you for the data. Where was this displayed? Must've missed it :(

Dear Anon 11AM 17 Feb'14,
When it was unveiled, the SAR-21 was described as a balanced weapon with the c.g. roughly at the pistol grip. Readers may recall the somewhat dramatic Army Open House demos during which the demonstrator would throw the SAR-21 on the ground to show off its rugged construction. There was also a clip that showed a SAR-21 being run over by a Land Rover.

The built-in 1.5x optical sight on the SAR-21 has led to a noteworthy rise in number of marksmen in SAF units compared to the M-16 era. The factory zeroed feature also saves an immense amount of time when the rifles are drawn by NSmen.

Having said all that, you are right in pointing out that there are benefits from buying off-the-shelf. The SAR-21 does the job but isn't the model answer for all tactical situations. The picture of the RSN personnel with foreign-sourced firearms says it all.

Dear Anon 5:21PM 16 Feb'14,
Yes, I have just such a scale... *grin*

btw, has anyone noticed that the Belgians adopted a different design philosophy for their F2000 rifle? The weapon was designed with minimal openings to avoid fouling the firing mechanism with debris.

Best regards,


Anonymous said...

hi david,
i mentioned the BMCR's similarity with the FN2000's forward ejection system, and the STK guy mentioned about the FN's unconventional chamber check (flip-up housing) while showing me how it's done on the BMCR (slides the cover plate).

Anonymous said...

The STK guy also talked about an add-on heatsink that would allow the BMCR to fire continuously like an LMG without overheating.
Absolutely no idea how that's gonna look or work, but they're working on it.

David Boey said...

Dear Anon 9:46 PM,
Thank you for the additional tidbits.

re: LMG. One hopes STK is aware the BMCR cannot be all things to all men (or women). Is STK designing a new mag for the BMCR like the 100-round C-Mag? A constraint will be the magazine capacity. Will the BMCR have a bipod, possibly a longer barrel too? Once all this is added, it takes away the "shortest bullpup design in the world" tagline.

What the BMCR needs is a more sexy name.

And the CMCR needs more pleasing aesthetics. Gunsmiths from Darra (in Pakistan) make more pleasant looking firearms from their rudimentary workshops.

Best regards,


Anonymous said...

I'm Anon 9:46 PM
The STK guy meant LMG as in sustained firing and not a conversion into LMG via c-mags etc.

which brings up the question - can the BMCR be converted into 9mm ala the Tavor?

the cmcr looks fine to me, just a tad long-ish.

Anonymous said...


I don't think a bullpup can ever be a LMG. The action is too close to the cheek.

Sss said...

Both the Micro Tavor and the Compact Tavor have overall lengths that are shorter than the BMCR - The CTAR at 640mm with a slightly longer 380mm barrel.

There are a few bullpup LMGs, the Chinese Type 95, the Steyr AUG HBar and the British L86A1 - the latter of which was converted to a designated marksmen rifle.

I'm actually a little surprised the Army hasn't updated the Ultimax 100 or chosen a new SAW. Are our boys still running around with Mk3s?

Anonymous said...


Could you do me a huge favour and show me the different Ultimax Mk versions? I still can't find a reliable source.

Anonymous said...

ST has a real attitude problem. Put their weapon on display, but get suspicious when people show some curiosity. What position of power are they in to decide what kind of interest people can and cannot show- being govt linked? C2D my ass.

David Boey said...

Dear Sss,
ST Engg's news release claims the BMCR is the world's shortest bullpup design. I hope they did their research properly before clearing that NR.

It may surprise you that some of our NS units are still running around with the Mark 2. This means you cannot change a hot barrel without mittens, unlike the Mark 3 which has the carrying handle attached to the barrel to expedite quick changes.

Best regards,


Sss said...

Anon @ February 18, 2014 at 2:15 PM

Basic data of the Ultimax 100 can be found at World Guns:

More detailed info on the Mk4 & Mk 5 is on, as they were in the running for the USMC's IAR contest - which the HK M27 IAR (a Mk416 derivative) won.

Apparently, there's a Mk 8 version floating around that STK showed of at SA2012:

The Mk2s were crap when I was in NS in the late 1980s - I still recall the thick welds, the propensity for the magazine to pop out (had to sign 1206) and the jamming issues with local made blanks. The Mk 3 were better, but the placement of the skinny handle made it difficult to carry.

Sss said...

Apologies, the Defensereview links are:

Anonymous said...

Thanks for the source. If the two are distinguished by the different carry handle placements, Mk2 and Mk3 are the most common variants in service today. I have not seen any other variant.

Inexplicably the Mk3 has been advertised since 1990 and to my knowledge been fielded since 2006. I venture SAF is keeping the older marks for their serviceable lifespan. Brown patches and thin black paint flaking off still counts as serviceable.

About jamming issues with plastic blanks, the M-16 and SAR-21 suffer as well. I suppose it is easier to adjust the gas system on the SAR-21 but am not sure if it's allowed.

Sss said...

Yep, still the old Mk 3:

With plastic blanks, the locally manufactured ones often didn't have enough charge to cause the bolt to cycle back all the way. You could tell them from the imported versions by their melted 'heads'. The imported ones had a scored X pattern at the tip that let them 'pop' open with the right amount of gas pressure to cycle.

OwnTimeOwnTarget said...

Why must have conventional version?

Got advantage ah?

Anonymous said...

Where is cocking handle?

Anonymous said...

Greetings from a Malaysian firearms enthusiast,

I believe that's more of a mid-eject system rather than a true forward eject system like the Kel Tec RFB. Few years ago Magpul came out with their Personal Defense Rifle prototype which had more or less the same eject system as this one. Nice looking rifle though.

David Boey said...

Dear Anon 7:07PM 19 Feb'14,
The cocking handle can be seen in the second image. It's the sliding piece held back by the thumb.

Dear Anon above,
Spent casings are ejected forward from the chute and not laterally like on the Steyr AUG or M-16. The casings are flung out to a distance of around 3+ metres. The STK fella described it as a forward ejection system.

Best regards,


Anonymous said...

Thanks David.

"The cocking handle can be seen in the second image. It's the sliding piece held back by the thumb."

Strange. It seems to be very unergonomic and I dont understand the whole idea.

According to me, STK products like Ultimax MK3 with long Picatinny rail and SAR-21 are quite good constructions in comparison with others, especially with "constant recoil" principle and low fire rate of 450-600 rpm (perhaps practically 550 rpm).
Any info of fire rate of BMCR?

BTW. It is interesting that in whole word, only Singapore (ST Kinetics) and Poland (Goverment program + FB Radom) started in last years programs of new assault rifles both in conventional and bullpup configurations. Poland started first and with more complex project of MSBS 5.56, in which conventional rifle and bullpup rifle have to be with common, interchangeable upper receiver and more common parts. Poland started with classic assault rifle first, which is almost comleted in technical terms, bullpup rifle is under first live-fire trials.
Let see who will be first in this race.

Anonymous said...

*claps*( sarcastically ). The guys here are truly very knowledgeable in terms of weaponry and keep up to date with the latest news and information on weapons. Have u guys given a thought about how stk are going to attach the grenade launche and the sights and how heavy the weapon would be? Think about it. I have been hearing about the new SAW weapon made by STK for a couple of years and even displaying at army open house but sad to say even elite units (which i won't disclose) are still using the Mark 2,3 and 3a. I see that this bmcr has better sights, which uses the red dot laser rather than e 1.5x scope, but would stk risk e money for nsfs or nsmen to use it? I think not. It would be more costly to repair or getting it replace if it gets damaged or unusable. Do you critics think so? So i tink the Army would rather buy weapons from reputable companies as the weapons are proven in war rather than making weapons. Like the m16a2 with rails, where the operator could attach devices, sightsor anything,depending on mission.
I will not go any futher as i have been an operator for a number of years and would say that i am really sad how the army equip the soldiers.

Mike F said...

I have a feeling the CMCR is to replace the current SAW.

NKRI said...

Wow....Singaporeans rifles look so advanced. Indonesia also has SS-2 rifle produced by Pindad. It's very accurate, we consistently win in AASAM and AARM military shooting competition.

highdiver_2000 said...

Hi David, where are the operating controls located for the BMCR (safety, firing selector)? Apologies if I missed it.

Anon @ 3.24pm. SAR 21 with GL are issued with with 3rd party scopes. So any issues about NS staff using expensive scopes would have been ironed out.

David Boey said...

Dear highdiver_2000,
The BMCR firing selector is on the top part of the pistol grip. It can be seen in the last image just above the watermark.

Best regards,


PakChiewCheng said...

Wah Piang!

Got Indon fellow here want to compare Singapore firearm with something called PinDud?

Hallo PinDud SS2 is copy of CN CAL (licensed) and barrel is made in Korea leh.

If you say Indon shooter at ASEAN meet very good, OK lah I pancan you and also say very good.

But come on lah, Pindud? Seriously?

Sure or not bruther?

PakChiewCheng said...

CMCR to replace SAW makes sense. Hope they come up with some sort of reliable barrel which doesn't fall off and have to use rubber band.

PakChiewCheng said...

Singapore must really marketing gun better mah?

Spend so much money develop but cannot sell, only small amount.

Maybe put in movie?

SAW good for killing zombies.

NKRI said...


CN-CAL? I don't know any rifle with that name.
The previous SS-1 is based on FN FNC, but the SS-2 is a new design.

TNI soldiers with SS-2, not only consistently win in ASEAN's AARM competition, but also beating US, UK, NZ and Australian soldiers in multiple AASAM events in Puckapunyal, Australia.

If Pindad is really "Pindud" that manufactures bad why TNI consistently wins in these events?

Anonymous said...

Anon 3:24 PM

Now you've said it. I was going to point out things like how thick the rifle appears and others you have mentioned. But sure get bashed by the trolls who think everything about the SAR-21 is best, start accusing me of not understanding the advantages of the factory zero etc etc.

David Boey said...

Dear Kilroy,
Thank you for getting in touch.

Have sent you a follow-up query. Email again? TY.

Warm regards,


Unknown said...

Seeing the coments around here, I am informing you that a smaller bulpup means that the length from the loading chamber face up to the end of the stock ending is the smallest. What the barrel is adding to the length of the riffle is not tooked in to acount. It matters only the action of the rifle.