What Does a Bullet Hole in Glass Look Like? (2026)

What can you tell by looking at bullet holes in glass? (Entrance vs. Exit Holes)

Quick visual answer: If you want a fast reply to what does a bullet hole in glass look like, think small and neat at the entrance and larger, ragged or conical at the exit, with lots of caveats. The exact look depends on the glass type, the ammo, the shot angle and the speed of the bullet.

For a quick field reference, photograph both sides with context and a scale, and compare with a short guide such as this glass analysis guide before disturbing anything. A good photo set helps investigators and keeps the scene intact.

Entrance holes are usually smaller and have a relatively smooth rim when the shot hits straight on. In annealed glass an entrance may show a small cone and short radial cracks; in tempered glass you often see a starburst or petal pattern around a neat central point.

Exit holes tend to be larger and more irregular, with a cone-shaped bevel that opens toward the far side. You will often find more spallation and outward-facing fragments at the exit, because tensile stresses peak on the far face and punch out a larger plug.

Radial cracks look like spokes and come from the impact point outward, while concentric or ring cracks are circular fractures that form around the impact like ripples. At a glance, radial cracks usually indicate where the impact energy radiated, and concentric rings can suggest a tempering response or a later propagation pattern.

An oblique shot rarely makes a round hole; instead you will see an ellipse with the longer axis aligned to the bullet path. Examining the major and minor axes of that ellipse helps estimate the shot angle, but measured estimates are best left to trained examiners.

Do not touch or clean the hole; cordon the area and call authorities immediately. Moving fragments or wiping the glass can destroy soot, residue and fracture sequences that investigators need.

Photograph both sides and include a metric scale; take wide context, mid-range and close-up photos and label which side is inside or outside. Good photos that show the pane in place and annotated orientation are invaluable.

Collect loose fragments only with gloves and clear labeling; place shards into sealed containers and record who handled them. Only do this if investigators explicitly ask you to, otherwise leave all material in place.

A Review of How the Physical Properties of Glass Explain the Shapes of Bullet Holes

Glass is not one uniform material, and that matters a lot when answering what does a bullet hole in glass look like. Different glass types break differently because of how they were made and how they handle stress at high speed.

Annealed or float glass, the common window pane, usually fails with conchoidal fractures and long radial cracks that spider out from the impact. The rim can be sharp and irregular and the cracks often start on the opposite face where tensile stress peaks during the short impact event.

Tempered or safety glass is heat-treated so it shatters into small cubical fragments and often shows a “petal” or starburst pattern at the entry. Tempered panes tend to fragment dramatically, and that can reduce visible exit plugs but makes the surface very chaotic to interpret.

Laminated glass, like a car windshield, uses an interlayer (often PVB) that holds shards together and changes how fragments expel. The interlayer can prevent a clean exit plug and instead produce adhered fragments and spallation, so the exit may look like compacted glass stuck to the interlayer rather than a large punched-out cone.

On a basic mechanical level, a high-speed impact sends a compression wave into the glass at the strike point and creates tensile stresses on the far side. That is why radial cracks frequently start on the opposite face and why the far face tends to fail with larger, punched-out damage.

Thickness and layering also matter: thicker glass usually shows longer radial cracks and more energy dissipation, while laminated structures reduce plug ejection but increase adhered spall inside the interlayer. For precise patterns and lab-style interpretation, see trusted resources on controlled testing and lab glass testing.

Characteristics of fired bullets on different target materials (caliber, projectile type and velocity effects)

Many people assume the hole diameter equals the bullet caliber, but glass behavior complicates that idea considerably. The projectile can deform, tumble, or fragment, and glass breaks in ways that change the visible opening size.

Full metal jacket bullets that remain stable in flight often make cleaner punched holes and more predictable radial crack patterns than expanding or fragmenting rounds. Hollow-point rounds or those designed to open on impact usually create irregular holes with larger surrounding fractures and secondary glass fragmentation.

Shotgun pellets produce a very different picture: many small perforations across a patch with heavy scabbing and splintering of the glass, and the collective damage is often more useful than any single pellet hole. Low‑velocity rounds sometimes look cleaner because they have less energy to shatter panels, but this is not a hard rule.

Examples help illustrate variability: a .22 can make a deceptively small hole but may tumble and carve a large fracture zone, while a 9mm often shows a neat entry and a bigger exit plug. Larger calibers like .45 will generally disturb more glass, yet the exact outcome depends on glass thickness, distance, and the angle of impact.

Because of this variability, forensic teams rarely assign a caliber from a hole alone without lab comparison and test firings on matching glass. Photographs that capture the entire scene and any fragments are the best evidence for later classification.

When you take photos, note the ammunition if known and describe the glass type and thickness if you can; this contextual data helps experts compare field observations to controlled tests.

For more detailed procedures and lab approaches, search procedural guides or consult a forensic lab to see how controlled firing tests are conducted on similar panes.

Direction, angle and sequence: how fracture patterns reveal shooter position and shot order

One of the most useful on-scene rules is simple: the entrance is generally smaller and the exit points away from the shooter. The bevel of a conical exit plug points toward the exit side, so the cone opens toward where the bullet left the pane.

Oblique impacts make elliptical holes with the major axis aligned to the bullet path, and comparing the two axes gives a rough estimate of the impact angle. A photo from straight on, with a metric scale, allows later measurement of major and minor axes to calculate the approximate angle of incidence.

Sequence of shots can often be read from how cracks terminate: a newer radial crack will usually stop at an older crack rather than cross it. This “terminating crack” rule helps forensic examiners place shots in order when the pane retains clear radial lines.

But there are important limits: tempered glass often fragments so thoroughly that sequence is impossible to read, and subsequent handling or environmental damage can erase termination clues. Overlapping shots, multiple entry points, and laminated interlayers may also hide the ordering evidence.

Because of these complexities, photographers and first responders should avoid moving the pane and should document everything with multiple angles and scales. Doing so preserves the fracture geometry for laboratory sequence and direction analysis by specialists.

Forensic investigation of bullet holes for determining distance from target (residue, pattern analysis and limitations)

Estimating distance from a bullet hole in glass is possible but rarely exact on-scene; investigators look for soot, gunshot residue, stippling and the pattern of fragments to get a range bracket. Glass alone is a tricky medium for range estimation, so lab tests are usually required.

Lab work involves firing the same ammunition at matching glass under controlled conditions to compare soot patterns, spallation, and fracture morphology. This controlled testing is why forensic labs maintain reference collections and why distance estimates are phrased probabilistically rather than as precise measurements.

Useful indicators include visible soot deposits or GSR on the glass surface, which point to close-range fire if they are present and undisturbed. However, soot can be wiped away or obscured, and the absence of residue does not equal distance because environmental factors and glass type influence retention.

Another observation is fragment dispersal behind laminated glass; closer shots can drive more fragments deep into the interlayer while distant shots may leave less internal spalling. Still, the same shot at different angles or with different bullets can produce very different dispersal, so context matters.

Because of these variables, investigators treat on-scene range estimates as preliminary until lab comparisons and residue chemistry confirm patterns. Readers should understand that precise range finding from a window is a technical task best handled in a controlled laboratory.

For practical guidance on what examiners test and how evidence is handled, many practitioners refer to procedural documents about testing and reporting, including practical manuals on forensic glass examinations.

This article is for information and education only and is not a how-to for criminal activity; always contact law enforcement and qualified forensic specialists if you encounter ballistic glass damage.