A bullet hit squib is a pyrotechnic, practical special effect device used in filmmaking, television and theatre to simulate the appearance of a person or an object being shot. When used on an actor as a blood squib, an explosive charge ruptures the costume and fake blood packet, expelling its contents through the resulting hole. Devices used similarly on props, such as walls and cars, blow out predrilled, filled and painted holes.
For blood hits, the device comprises a squib, simulants sealed in a bag imitating bodily fluids, tissues or both, a protective shield and padding. The device is usually concealed in specially prepared clothing and weakened at the effect location, instead of on bare skin.
The squib is connected to a power source and a remote, detonated by the actor or a crew member to achieve the effect. Multiple squibs may be used and triggered either simultaneously or sequentially to represent different types of gunfire.
While used for dramatic effect to illustrate the demise of a character, the visual result does not accurately reflect the physical characteristics of real gunshot wounds. Nevertheless, the stylised and exaggerated aesthetic is widely recognised by filmmakers and audiences alike, such as in the main figure, bullet holes are blown outwards and blood projects through the entire jacket.
Historical context, usage and development
From early to modern day use Bullet hit squibs were first used in the film industry as early as 1943 in Bataan, as shown in the adjacent image, and 1955 in Pokolenie, with the latter using fake blood added in a condom and a squib, a technique still widely in use today. The use of squibs in filmmaking has become a widely accepted and well-established technique for creating convincing and realistic depictions of violence. This approach has been used in many classic films such as The Matrix (1999), Goodfellas (1990), and The Terminator (1984).
Despite advances in digital effects, practical squibs are still widely used due to their ability to produce authentic, in-camera effects that enhance the overall atmosphere and intensity of a scene. While CGI can be employed to augment or replace squib effects in certain situations, the physicality and immediacy of practical squibs continue to make them a valuable tool in special effects for film and television. Bullet hit squibs can also be used in first responder moulage training and music videos, for example 99 Problems (2004).
Related advancements The earliest patent related to the manufacturing and chemical composition of bullet hit squibs was submitted in 1991. Since then, from the 2000s, a number of notable design or manufacturing features have been patented. Advancements include specific methods and chemical compositions to manufacture the squibs themselves, such as without heavy metals; a wearable, reusable pneumatic system that eliminates the need for explosives by using compressed air to expel fake blood through a small outlet. Another design incorporates traditional squibs but is pre-manufactured and nearly fully assembled, reducing on-set assembly time. This standardised design, however, limits customisation in terms of blood volume, spray pattern, etc.
Device and costume preparation and implementation In film productions, multiple crew members, including pyrotechnicians and costume designers, work together to create the effect. Pyrotechnicians are responsible for building the squibs, while costume designers prepare multiple identical outfits for the actors. Collaboration among writers, directors, producers, and actors is essential for determining the number and placement of squibs, as well as costume design. Depending on the budget, productions typically use between three and six, and sometimes eight costumes to accommodate various takes, camera angles, out of sequence filming, dress rehearsals, backups and tests. This can become costly, especially for low-budget filmmakers, leading to trade-offs between the number of character deaths, takes (i.e. costume duplicates), and the number of squibs (i.e. multiple hits) used. An overview of the device and costume preparation is illustrated in the gallery below.
Bullet hit squib device
The desired aesthetic of the blood hit is usually first decided, for example, an entry or exit wound, i.e. fake blood erupting as a gushing stream or a spray of fine mist respectively, and the absorbency of the costume fabric determine the amount to be used, typically 10–30 ml. It is typically filled in a small balloon, packet, or condom, followed by a grooved protective plate and padding. The positioning of the squib above or below the blood pack enables the burst to be customised. For example, placing the squib beneath and aligning it to the lower half of the blood pack oriented vertically produces an aerosolised burst followed by a stream, as shown in the adjacent figure.
These parameters and the fabric strength then determine the squib size. The actual squib is a flat, disc-shaped high explosive, containing an integrated igniter or glow wire, about 0.5–2 mm thick and weighing between 2 and 384 mg, Usually, the smallest possible grain size to achieve the effect is used, although the most common variants are 0.5 and 1.0 grain (33 to 65 mg). For comparison, a low explosive party popper is approximately 0.25 grains (15 mg), and a small firecracker is about 2.5 grains (150 mg).
A low profile is intended during the assembly to minimise bulge through the costume. The device is secured with duct tape, leaving a small front window for the simulant to burst through. Various fluids, such as fake blood, water (rehearsals), glycerine (night scenes), and/or solids like dust and feathers (gunshot aesthetic on a down jacket), cotton or meat are used depending on the desired effect. A complete bullet hit squib assembly weighs approximately 50 g, measuring 100x50 mm in length and width and 25 mm thick.
Costume considerations for blood squib effects
Stage clothes modified for actors playing characters killed on screen are modified to conceal special effects equipment such as squibs and wiring, such as the holed and bloodied scrub top shown in the adjacent image. When preparing these costumes, considerations include script and scene requirements, how easily squibs can be integrated, hidden and seen before and after triggering respectively, aesthetics, lighting conditions and budget constraints. As a result, they play an important role as a figurative canvas, portraying violence and death through bursts of blood, frayed bullet holes and the stains. For gunshot wounds depicted on bare skin, prosthetics may be used instead. Several "distress doubles" or "stunt" costumes with pre-scored bullet holes are usually prepared for main characters to accommodate multiple takes and camera angles. These copies may be a size or two larger to cover for the additional equipment and padding. Additionally, a "hero" or "picture" costume is used for earlier scenes and close-ups without squibs.
Preparation and integration Squibs are discreetly integrated into costumes to minimise visibility on screen, with examples shown in the gallery beneath. The fabric is intentionally weakened using techniques such as cutting, sanding, scoring, grating or plunging a scoring tool producing a crosshatch pattern, often required by health and safety legislation and loosely glued or taped back together. Small incisions in the fabric without actually cutting through it can reduce the visibility of scoring marks. Squib placement is kept consistent across all stunt costumes. To ensure that the fake blood is propelled outwards, squibs are aligned with precut bullet holes and securely attached. They are connected to a wired or wireless trigger, power source, and sometimes a programmable controller for synchronisation. The electronics can be placed within the costume or off-camera. Test fires and rehearsals are performed to check for faults and to make adjustments to timing or the amount of fake blood as needed.
While most outfits can only be used once due to the destructive nature of squibs on the material, jackets (e.g. waterproof, parka and down) and other durable clothing may be reused if the bullet holes are crosshatched in well-defined, clean-looking cuts. These garments can be wiped clean and reset for additional takes, such as the jacket in the main figure featuring pre-cut holes used for demonstrations. Other advantages include their ability to conceal devices, provide additional padding, support multiple squibs and be easily worn and removed, thereby minimising the risk of accidental premature rupturing. The main disadvantage of reusing jackets is that the reset requires more time between takes. Stronger fabrics may require more significant weakening or the use of a more powerful squib to ensure the bullet hole can be blown open, otherwise the squib may not rip up the fabric at all or in such a way that does not resemble a bullet hole.
During filming Depending on the availability of hero and stunt costumes, the scene's length and the actor's comfort, the prepared outfit may be worn just before the shot, throughout a scene, or even for the entire day. However, it is advisable to minimise the time spent in the stunt costume to avoid accidental damage to the squibs, such as sitting against a chair with back squibs or spilling liquids that could affect the costume or the equipment.
Once a take is successful, the wardrobe department photographs the "aftermath" to maintain continuity and prepares for the next take, scene, or clean up, or saves them for reshoots. In some cases, bullet holes may be enhanced for subsequent scenes. Costumes modified with squibs are not usually returned to the costume shop due to the irreversible damage caused by the pre-scoring on the fabric and the modifications inside.
Post-production In post-production, techniques are often used to minimise the visibility of squibs and fabric scoring. Footage may be cut just before the squibs are triggered, or the use of digital editing tools such as reference frames and content-aware fill are also possible to some extent. Additionally, sound design further enhances the impact of gunshot effects.
Production costs for bullet hit squibs
The making of bullet hit squib effects involves several expenses, including raw materials, labour, permits, and costumes. The primary component, squibs, generally cost between $20 and $60 each. Fully assembled devices – including fake blood, plastic packets, duct tape, wiring, and protective shields – can cost around $150–300. Preparing squibs for a shoot can require approximately 10–20 minutes per unit, an entire day for assembly and another day for costume setup, typically overseen by specialised pyrotechnicians who manage setup, testing, and detonation during filming.
Costumes are another significant budget factor, especially with multiple outfits required to accommodate retakes. Using jackets shown on the right for a winter shootout scene as an example, with one reserved as the hero costume, one for testing, three for the stunt and another for dress rehearsal, totalling an estimated wardrobe budget of $3,000 at around $500 each without accounting for other wardrobe pieces. Fitting 30 squibs, or six each to the testing, stunt and dress rehearsal duplicates, would cost approximately $4,500-9,000, bringing the material costs alone for this stunt to approximately $7,500-12,000. In certain cases, selecting a more powerful squib (such as D80-1 instead of D80-¼ or D80-½) allows costumes to omit the pre-scoring step, enabling unused costumes to be retained or refunded after filming.