Image credit
- Title
- File:SIG SG 542 2018-1.jpg
- Author
- KickerTom(attribution required)
- Licence
- CC BY-SA 4.0
- Source
- https://commons.wikimedia.org/wiki/File:SIG_SG_542_2018-1.jpg
How Muzzle energy is calculated
E = ½ · m · v²
Inputs
- m9.525 g147.0 grverifiedsourcePublished as 147 gr; 1 gr = 0.06479891 g exactly.
- v853 m/s2,799 fpsverifiedMeasured with a 558.8 mm barrel, not this arm's 465 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 558.8 mm853 m/s2,799 fpsverifiedsourceBallistics table of the cited article.
Assumptions
- This figure belongs to a 558.8 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.
No input on this calculation carries a clickable source yet.
How Free recoil is calculated
E_recoil = ½ · m_firearm · v_recoil²
Inputs
- m_firearm3.55 kg7.826 lbestimatedFrom the Wikipedia infobox for the SG 540 family, uncited there, where it is given for the SG 542.
- v_recoil2.289 m/s7.509 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.
No input on this calculation carries a clickable source yet.
How Capacity is calculated
as published for the primary chambering
Inputs
- capacity30estimatedFrom Wikipedia's variants section, uncited there: normally 20- or 30-round box magazines, with 5- and 10-round magazines also made; 30 is the largest.
No input on this calculation carries a clickable source yet.
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
- m9.525 g147.0 grverifiedsourcePublished as 147 gr; 1 gr = 0.06479891 g exactly.
- v853 m/s2,799 fpsverifiedMeasured with a 558.8 mm barrel, not this arm's 465 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
- mass9.525 g147.0 grverifiedsourcePublished as 147 gr; 1 gr = 0.06479891 g exactly.
- diameter7.85 mm0.3091 inestimatedsourceNo free dimensional standard publishes the NATO round under that name. Borrowed from the C.I.P. datasheet for the commercial .308 Winchester (G1), which shares the chamber; the two are not interchangeable at the pressure limit.
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
- mass9.525 g147.0 grverifiedsourcePublished as 147 gr; 1 gr = 0.06479891 g exactly.
- velocity853 m/s2,799 fpsverifiedMeasured with a 558.8 mm barrel, not this arm's 465 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
- n30estimatedFrom Wikipedia's variants section, uncited there: normally 20- or 30-round box magazines, with 5- and 10-round magazines also made; 30 is the largest.
- rpm725 rpmestimatedMidpoint of the 650–800 rounds/min range the Wikipedia infobox gives for the whole family, 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.
No input on this calculation carries a clickable source yet.
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
- Rifle
- Action
- Self-loading
- Fire modes
- Semi-automatic
- Burst
- Fully automatic
- Operating system
- Gas, long-stroke piston
- Roles
- Designed in
- Switzerland
- Introduced
- 1977
- Production
- 1977–present
Dimensions and mass
- Mass, empty
- 3.55 kg7.826 lbestimated
From the Wikipedia infobox for the SG 540 family, uncited there, where it is given for the SG 542.
- Magazine, empty
- not recorded
- Length
- 1,000 mm39.37 inestimated
From the Wikipedia infobox for the SG 540 family, uncited there, where it is given for the SG 542. Stock extended.
- Length, folded
- 754 mm29.69 inestimated
From the Wikipedia infobox for the SG 540 family, uncited there, where it is given for the SG 542. Stock folded.
- Width
- not recorded
- Height
- not recorded
- Barrel length
- 465 mm18.31 inestimated
From the Wikipedia infobox for the SG 540 family, uncited there, where it is given for the SG 542.
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
- 600 m656.2 ydestimated
From Wikipedia's variants section, uncited there: the SG 542's rear drum adds a 600 m setting to the SG 540's 100, 200, 300 and 500 m.
Operation
- Cyclic rate
- 725 rpmestimated
Midpoint of the 650–800 rounds/min range the Wikipedia infobox gives for the whole family, uncited there.
- Trigger pull
- not recorded
- Effective range
- not recorded
- Units produced
- not recorded
- Launch price
- not recorded
Chamberings
- 7.62×51mm NATOprimary30 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.
- SIG SG 5421,000 mm39.37 inheight not recorded
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. SIG SG 542 records no height, so its outline is drawn at the type's proportion. That height is part of the shape, not a measurement.
Gallery
Image credit
- Title
- File:Ecuadorian Army soldier participates at a UN exercise.jpg
- Author
- Senior Airman JoAnn S. Makinano
- Licence
- Public domain
- Source
- https://commons.wikimedia.org/wiki/File:Ecuadorian_Army_soldier_participates_at_a_UN_exercise.jpg
Detail
The SG 542 is the 7.62×51mm NATO member of SIG’s SG 540 family, the full-power battle rifle built on the same long-stroke gas piston and two-lug rotating bolt as the 5.56mm SG 540 and SG 543. Like the rest of the family, it was designed in Switzerland but, because of Swiss federal restrictions on arms exports, series-produced at Manurhin’s plant in Mulhouse, France; FAMAE in Chile still builds it under licence for the Chilean armed forces.
The encyclopedia puts the differences from the SG 540 down mainly to the larger, more powerful cartridge. The mechanism is otherwise the family’s: a closed-bolt, hammer-fired action with a three-position gas regulator, one setting of which serves for launching rifle grenades from the flash suppressor, and a combined safety and selector for single shots, three-round bursts and automatic fire. The SG 542 normally takes 20- or 30-round box magazines, with 5- and 10-round magazines also made, and its rear diopter drum adds a 600 m setting to the SG 540’s four. FAMAE has also built it for the Canadian civilian market, and it has been issued to the armies of Bolivia and Ecuador among others.
Every figure on this page is an uncited encyclopedia figure given for the SG 542 within the SG 540 family’s article, and is recorded as an estimate; the cyclic rate is the family’s published range, not one measured on this model. No maker specification sheet, rifling twist or muzzle velocity paired with a stated barrel length was found.
References
This entry's own bibliography. Every citation key on this page resolves into this list.
- SIG SG 540 · Wikipedia · 1372688728 · read 2026-09-24 · CC BY-SA 4.0
Last verified 2026-09-24 · review status: draft