Brügger & Thomet MP9
Image credit
- Title
- File:MP9 23-11-2010 11-00 00224.jpg
- Author
- Kusi97(attribution required)
- Licence
- CC BY-SA 4.0
- Source
- https://commons.wikimedia.org/wiki/File:MP9_23-11-2010_11-00_00224.jpg
How Muzzle energy is calculated
E = ½ · m · v²
Inputs
- m7.452 g115.0 grverifiedsource115 gr as published, converted to grams.
- v359.7 m/s1,180 fpsverifiedMeasured with a 101.6 mm barrel, not this arm's 130 mm. Velocity outside the sourced range is not projected.
1 of 2 inputs link to their source.
How Muzzle velocity is calculated
nearest sourced barrel length, no extrapolation
Inputs
- v at 101.6 mm359.7 m/s1,180 fpsverifiedsource1180 fps as published.
Assumptions
- This figure belongs to a 101.6 mm barrel. It is shown because it is the closest measurement that exists, not because it applies here.
1 of 1 inputs link to their source.
How Loaded mass is calculated
m_loaded = m_empty + m_magazine + n · m_cartridge
Not calculated: m_magazine has no sourced figure yet. Nothing is substituted for a missing input.
Assumptions
- One magazine, filled to the stated capacity. Spare magazines, optics, slings and lights are the owner’s, not the arm’s.
2 of 4 inputs link to their source.
How Free recoil is calculated
E_recoil = ½ · m_firearm · v_recoil²
Inputs
- m_firearm1.4 kg3.086 lbestimatedsourcecited by the infobox to a B&T datasheet PDF that now 404s; B&T's current product page instead gives 1.7 kg including an Aimpoint sight and 30-round magazine, a different, non-comparable loadout, so that figure is not recorded here.
- v_recoil1.915 m/s6.282 fpsestimated
Assumptions
- Propellant gas momentum is excluded: ARMAG does not record charge weights. This is therefore a lower bound on the real free recoil, consistent between entries but smaller than a figure that includes the gas term.
- Free recoil: the arm is unrestrained. Stock design, muzzle devices, stance and shooter mass are not modelled, because none of them is a property of the arm.
1 of 2 inputs link to their source.
How Capacity is calculated
as published for the primary chambering
Inputs
- capacity30verifiedsourceManufacturer's own product page lists 20- or 30-round B&T magazines; 30 rounds recorded here as the larger option.
1 of 1 inputs link to their source.
Derived figures
Computed from the sourced values above. Open ƒ on any figure for the formula, its inputs, and the assumptions it makes.
How Momentum is calculated
p = m · v
Inputs
- m7.452 g115.0 grverifiedsource115 gr as published, converted to grams.
- v359.7 m/s1,180 fpsverifiedMeasured with a 101.6 mm barrel, not this arm's 130 mm. Velocity outside the sourced range is not projected.
1 of 2 inputs link to their source.
How Sectional density is calculated
SD = mass(gr) / (7000 · diameter(in)²)
Inputs
- mass7.452 g115.0 grverifiedsource115 gr as published, converted to grams.
- diameter9.03 mm0.3555 inverifiedsourceCartridge maximum, dimension G1.
Assumptions
- Reported in the conventional lb/in² so it is directly comparable with published figures.
2 of 2 inputs link to their source.
How Power factor is calculated
PF = mass(gr) · velocity(fps) / 1000
Inputs
- mass7.452 g115.0 grverifiedsource115 gr as published, converted to grams.
- velocity359.7 m/s1,180 fpsverifiedMeasured with a 101.6 mm barrel, not this arm's 130 mm. Velocity outside the sourced range is not projected.
Assumptions
- A competition classification defined by the IPSC and USPSA rulebooks, stated in their units. It describes a scoring category, not an effect.
1 of 2 inputs link to their source.
How Magazine dump is calculated
t = (n − 1) / (rpm / 60)
Inputs
- n30verifiedsourceManufacturer's own product page lists 20- or 30-round B&T magazines; 30 rounds recorded here as the larger option.
- rpm900 rpmestimatedsourcefrom the infobox, uncited there.
Assumptions
- Cyclic rate held for the whole magazine, no stoppages, trigger held down. A theoretical figure for comparing mechanisms, not a measured one.
2 of 2 inputs link to their source.
How Sight error at 1 mm is calculated
θ = atan(misalignment / sight radius)
Not calculated: sight radius has no sourced figure yet. Nothing is substituted for a missing input.
Assumptions
- Shows what a stated aiming error costs. The misalignment is the reader’s figure; the site does not claim how well anyone aims.
No input on this calculation carries a clickable source yet.
Specifications
Every row here is generated from the schema, so a figure recorded on this entry cannot be missing from the table, and the same rows, read the same way, are what the comparison shows.
Identity
- Type
- Submachine gun
- Action
- Self-loading
- Fire modes
- Semi-automatic
- Fully automatic
- Operating system
- Short recoil
- Designed in
- Switzerland
- Produced in
- Introduced
- 2001
- Production
- not recorded
Dimensions and mass
- Mass, empty
cited by the infobox to a B&T datasheet PDF that now 404s; B&T's current product page instead gives 1.7 kg including an Aimpoint sight and 30-round magazine, a different, non-comparable loadout, so that figure is not recorded here.
- Magazine, empty
- not recorded
- Length
- 523 mm20.59 insource
Manufacturer's own product page, stock extended ("Length min./max. 303 / 523 mm").
- Length, folded
- 303 mm11.93 insource
Manufacturer's own product page, stock collapsed.
- Width
stock extended, from the infobox, uncited there.
- Height
with 30-round magazine fitted, from the infobox, uncited there.
- Barrel length
- 130 mm5.118 insource
Manufacturer's own product page.
Sights and rifling
- Sight radius
- not recorded
- Sight height over bore
- not recorded
- Rifling twist
- not recorded
- Twist direction
- not recorded
- Grooves
- not recorded
- Sight graduation
- not recorded
Chamberings
- 9x19mm Parabellumprimary30 rounds
- .45 ACP25 rounds
Scale
A to-scale outline against family siblings. The dimensions are sourced; the shape is a representative outline for the type, and says so.
- Brügger & Thomet MP9523 mm20.59 in
Representative outline: the dimensions are sourced, the shape is not. Overall length, and barrel length where recorded, are drawn from this entry's own figures; the profile is a generic one for the firearm type and says nothing about this arm's actual contours.
Detail
The MP9 is not a B&T design in origin. It is a development of the Steyr TMP, the Austrian machine pistol B&T bought outright from Steyr in 2001 and put into service under its own name in 2004. It is a submachine gun small enough to holster like a large pistol rather than sling like a rifle. Where most guns this size use a simple blowback action, relying only on the bolt’s mass and a spring to hold the breech shut, the MP9 locks its barrel to the bolt through a short-recoil, rotating-barrel mechanism: barrel and bolt travel back together for a short distance after firing, and the barrel’s rotation only releases the bolt to continue rearward once pressure has already dropped.
The design reached a wide customer base for a specialist Swiss manufacturer, entering service with units including India’s Para Special Forces, Indonesia’s Kopassus, Russia’s FSB Alpha Group, and police tactical units across dozens of countries including France’s RAID and Belgium’s federal police, with recorded use in the War in Afghanistan. Beyond the standard 9×19mm Parabellum chambering, B&T also builds an MP45 variant in .45 ACP and has offered a version chambered for the low-recoil 6.5×25mm CBJ round it developed itself; because no free dimensional standard exists yet for that cartridge on this site, the 6.5mm CBJ chambering is not recorded in this entry’s data.
This entry’s barrel length, and its extended and folded overall lengths, are drawn directly from B&T’s
current product page and carry verified status; every other figure traces to the Wikipedia infobox,
mostly without an inline citation, and is recorded as estimated. The infobox’s own weight citation points
to a manufacturer PDF that no longer resolves, and the current B&T page instead gives a heavier figure that
includes a mounted sight and loaded magazine (a different measurement from an empty gun’s weight), so
neither figure is recorded as verified here. No twist rate is published.
References
This entry's own bibliography. Every citation key on this page resolves into this list.
- Brügger & Thomet MP9 · Wikipedia · 1347712286 · read 2026-09-09 · CC BY-SA 4.0
- MP9 submachine gun · Brügger & Thomet AG · read 2026-09-09
Last verified 2026-09-09 · review status: agent-populated