The amazing 6.5x25mm CBJ

Anthony Williams has written a fascinating account of his time spent shooting the Brugger & Thomet MP9 chambered in the diminutive 6.5x25mm CBJ round. The standard 6.5x25mm CBJ Ball1 round consists of a necked down 9x19mm NATO case with a 4mm (0.157″) tungsten bullet, weighing 30 grains, inside a 6.5mm plastic discarding sabot. Look what it does to armor …

9mm armor plate from a Russian APC

One of the rounds biggest advantages is that is can be used in any 9mm NATO gun with nothing but a barrel change.

The wide range of bullets. Including non-saboted subsonic Copper Solids and Frangible.

I highly recommend reading Tony’s article.

  1. It is officially refeared to as a “Ball” round but this is a misnomer. Ball usually refers to a Full Metal Jacketed bullet, not a saboted non-jacketed bullet. 

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Aurelien

    Seems to be quite effective against protected targets.

    I wonder what the “ball” ammo would do against unprotected people when not hitting a critical point.

  • Jesse

    What the hell is that bullet on the right? It looks like it’s made of Kryptonite. Is superman around?

    • Jesse, its a dummy round!

  • snmp

    If you take Amor percing 7,62 Tokarev you could have the same result

  • Your birthstone as a projectile! Those are some colorful bullets.

  • root man
  • Other Steve

    Hell, a barrel change on an MP9/TP9? Simple task of a barrel change huh? That gun has the most complex barrel of any gun I own! It would take a lot of time to make a new barrel for that gun. It looks like a really large AR bolt with a barrel attached, and all sorts of machining for the barrel guide… Eff that. This example is talking about a $2000 barrel!

    That said, I did consider awhile back about how hard it would be to do a 7.62×25 TP9, the straight mag is the obvious issue.

    Also, I I understand the law correctly AP ammo is legal for civilians in the states if it’s in a rifle caliber. Meaning 9mm would be illegal right?

    • Other Steve, no its not legal (without doing what you need to do with the ATF) for either rifle or pistol. Interestingly, these guys do not think their ball ammo is AP.

  • Other Steve

    Overall though te article makes me feel quite good about my TP9 SBR. I only wish I could get the angled vertical grip like the MP9. I will agree with the author that the MP9/TP9 SBR does ‘feel’ right, it’s still not as comfortable as my MP5 A2

  • Burst

    One of the more interesting bits on the 6.5mm (and one that isn’t included in that article) is the Saab developed 100-round drum. It lies parallel to the receiver, and is about the size of a soup can.

  • Al T.

    Considering that the 5.7 isn’t working for US LE, I fail to see why sub caliber hole punchers have any attraction. It is indeed neat, but useless unless your attached by the Transformers.

  • Tricky

    NATO has been looking to replace 9mm for a while now. They want something which can be used in both hand guns and PDW with better performance out of a longer barrel. For awhile it looked like 5.7 was going to be it, but its still up in the air. they had better pick something fast, because the current 9mm round is totally ineffective against modern body armor. Seems to me like all the rounds that are being talked about right now are to slow/small. The longest round possible is about 40mm long and has a base diameter of 12mm. A sabot or a plastic jacked bullet seems like a good idea to increase velocity. Maybe, the best thing to do is wait for caseless ammo and then make a short fat round which can be used in both hand guns and assault rifles. That way you can replace 9mm and 5.56 with one round.

  • moose

    oh god in heaven please get some coversion kits over here , imagine a ruger sr9 in this but then again all the liberal gun haters will go crazy like they did with 5.7x28mm well who nows maybe one of theys days

  • zack

    where can I get these my 9MM, lol

  • openmidedcro

    7,62 Tokarev FMJ does little in that case… B
    ut if you hit critical its different. In ex-yugo countries they use it to finsh boar hunt, if needed. Allways penetrates skull.

  • MrMaigo

    7.62 AP would make a much nicer hole…

  • kcoz

    Pretty interesting article. But all they really did is take a machine pistol(Not a new concept), and make some armour piercing ammo for it. Kind of like the Sabo rounds Modern tanks use. I do like how they did it with a 9×19 instead of creating a new round with totally different dimensions. Has alot better chance of being adopted by militaries that way I think.

    Does anyone have any idea if that kind of ammo would be legal for sale to civilians? Fans of the FN 5.7 would love it.

  • Beaumont

    Is this the same round the Swedes developed twenty-odd years ago for their homegrown Uzi variant? It always seemed an intruiging idea.

  • Redchrome

    Looks a lot like the 7.62×25 round that Leitner-Weise came up with some years ago.. a 10mm Auto (or for less neck forming, start with 9×25 Dillon) necked down to 7.62mm and loaded with a sabot to throw a .224 centerfire bullet like the 55gr from the M193 round.

    Smaller diameter bullets have better sectional density for a given weight, and higher speed if the weight is reduced, so they penetrate better. .357 Sig penetrates steel plate better than .40 S&W even tho the total energy is comparable.

    Fundamentally tho, you can’t cheat Newton. You can only optimize for particular problems. Something like this will beat armor well, but might not be as effective at putting down the flesh & blood on the other side. (Which is really a secondary problem, since you first have to beat the armor, if there is any, and we aren’t worried about a sporting kill in military matters).

  • iMick

    I find it fascinating that in all these searches for the “perfect” small arms cartridge since the early 1900s, regardless of application, all seem to end up with 6-6.5mm. You would think we’d have got the hint by now!!

  • MrMaigo

    Actually Steve AP ammo is NOT ILLEGAL by Fed. As I understand only 5.7 AP is restricted by… but then, who doesn’t know a LEO who can get you what ever you want?

  • A couple of comments:

    Effectiveness against unprotected targets is the big question mark which will only be fully resolved by combat experience. However, if you look at the gel test results in my article, both the full-calibre 6.5mm and sub-calibre 4mm bullets appear to cause far more disruption than 9mm FMJ ball (which is what they’re aiming to replace).

    Whether or not any army needs a new pistol/PDW round which can reach out to around 200m and punch holes through most body armour depends on how the army frames its small-arms requirements. Some may prefer to use carbines for that (the USMC seems to have decided on that, adopting the M4 to replace most M9). However, if they do want one, the 6.5×25 seems to have some clear advantages over the 4.6×30 or 5.7×28 in terms of performance, varieties of ammo types available and of course rapid conversion to and from 9×19, which minimises the costs and risks involved. I hear that Beretta are looking hard at this…

  • Alaskan

    I don’t see why NATO can’t get past it’s “We’re European..everything we do,the USA must follow suit”..

    It all brings me back to the first two World Wars. The USA’s Lend-Lease program..and all that.

    Then I think of World War 2 and the Russian and German pistols and their 9mm offerings..”cute” pistols that were great for executions(but those never happened..the victims “fell” on their own gun)
    but then(being an American) I remember that the US Military had issued the M1911/A1 in fight stopping .45ACP. and all went well.

    Why is it the United States has to follow Europe’s footsteps in regards to weapon standards?
    I get that NATO adopted the 5.56mm for “assault rifles” and this is a pretty common round..2nd only the the 7.62x39mm
    If you need rifle,you get a rifle..if you need a pistol(and you aren’t soft) get a .45ACP or .40SW.

    If you encounter someone wearing body armor,why keep shooting the body armor? That is wasting bullets. Just put one bullet in the head.

    I agree with the US issuing the M4 in place of the M9. Training someone on a long gun can be easier and since they have a point of contact(against the shoulder) their shots can be more on don’t want a stray bullet hitting someone else.
    Even the LAPD is issuing .40SW..

    My idea? Well since training is time spent away from doing patrol and other job related matters,use a “simple” gun for NATO..The Glock seems like a perfect candidate. I’m not a Glock fanboy,but when you have to train armies around the world,the simpler the better. Every form of media(news,television,video games,et al) know what the Glock looks like and what it does. It’s not german rocket surgery as H und K would have you believe (and I’m a fanboy of HK weapons)’s just simple..

    Caliber?..hard to say because even though there are loads for the .45,the .40SW is a bit less on the recoil side..

    TL:DR? (too long? didnt read?)
    Glock for NATO’s adoption as a standard pistol,in .40SW.

  • .40 S&W

    @Alaskan: The Army already issues fragmentation grenades.

  • Aurelien

    Alaskan, the US never follow Europe.

    7.62mm ? US. The brits wanted the .280 they built for the EM-2 rifle. The belgians wanted to retain the German 7.92mm kurz and built the FN FAL around it. The French did not give a damn and sticked to the 7.5mm.

    5.56mm, again, work of the US. The only word Europe had is the developpement of the SS109 by FN Herstal.

    So yes, the US went from .45ACP to 9mm Parabellum. The fact is, the stopping power of both is similar, and any further 9mm vs .45 comments would waste everybodys time.

    So to answer your question, the US followed Europe on one thing, the 9mm Parabellum. Boo-hoo. All other weapons specs ever have been pushed on everyone else by the US.

    And the Russians never used 9mm handguns during WWII. They used 7.62x38R revolvers and 7.65×25 pistols. The 9mm makarov guns game about in 1951.

  • Marc

    “I don’t see why NATO can’t get past it’s “We’re European..everything we do,the USA must follow suit”..


    Read up on how the US bullied the rest of NATO into adopting 7.62×51 mm, ONLY TO UNILATERALLY ADOPT 5.56×45 mm A FEW YEARS LATER.

    Your ideas on the effectiveness on small arms cartridges are preposterous as well. Uncountable WW2 soldiers want their lives back, which were taken by 9 mm and 7.62 mm SMGs.

  • Meltron

    MrMaigo Armor piercing ammunition is illegal for sale to civilians unless to Federal Agencies or Law enforcement.

  • Bryan S.

    my recolection was that is only retail, and only for handgun ammunition.

    Rifle ammo is stil OK in “AP” (the atf, as usual, is silly on what is ap and not) and the private sale and ownership of real deal AP rounds is not regulated.

    Honestly, most 7.62 nato rifles will punch through body armor anyhow… when you are talking rifles, its hard to stop that bullet.

  • CBJ are only planning to sell their conversion barrels and ammo to the military or law enforcement agencies anyway, so the question of AP or not isn’t really an issue.

  • spudfiles

    Alaskan, this is a quote from a major study on wound ballistics by the US Army Medical Department in 1962 (fascinating if somewhat gruesome read, can be found here:

    “From an analysis of these facts and the requirements for penetration of skin and bone, it can be readily appreciated that the .45 caliber bullet is of little value as a wound-producing agent except in the softer tissues and at near ranges. The bullet often fails either to penetrate or to fracture bone and practically never shatters bone in the manner common to the rifle bullet or fragment. The Japanese and German sidearms with muzzle velocities of approximately 1,100 f.p.s. were much more effective as antipersonnel weapons than the .45 caliber weapon. While the same bullet with its characteristics was used in the submachinegun, multiple hits probably compensated for the weaknesses, so apparent in single shots.”

    Your assertion that one should avoid having to penetrate body armour by aiming for the head is the justification by the Russians for using the SV-99 22LR rifle as an urban weapon -“If a target is closer than 100 meters, You don’t have to defeat a ballistic jacket. An exposed neck, face or head is just enough!”

    This is feasible if firing from a concealed position taking a shot at an unprepared enemy, but not always practical in a combat situation.

  • Jim

    this article was written in 2006.. i don’t think that we (the US) are in a huge rush to produce a PDW, regardless of caliber.. apparently the M4 is filling that position.. and with the new orders for the M9, it’s less likely that an odd caliber, or PDW will be selected any time soon.. regardless of performance.. the least effort will be expended to achieve the same effect.. and it seems like that’s been done already..

    you have to design requirements to the “room temperature IQ”.. less calibers, less platforms, the better..

  • Bill Lester

    If anyone wants a print copy, Mr. Williams’ article recently appeared in the Feb. issue of Small Arms Review. It’s available as a back issue from the publisher or you can possibly find it for sale at gun shows. Many times the older issues sell for $1-2 or so just to get them off the table.

  • spudfiles

    “it’s less likely that an odd caliber, or PDW will be selected any time soon.. regardless of performance..”

    In that regard, it seems odd that a discarding sabot round in 9x19mm firing a subcalibre hard penetrator commonly available, if one exists at all. This would bring many benefits enjoyed by the CBJ round in terms of velocity and penetration, without having to change anything about the weapon itself, and I don’t imagine that a nylon sabot and steel penetrator would be that much more expensive to manufacture than standard FMJ rounds.