Gunshot residue is composed of burnt and unburnt particles from the firearm's primer, propellant, bullet, cartridge case, and firearm. There are three types of gunpowder burning - degressive, neutral, and progressive. Gunshot residue can be detected through analytical methods like neutron activation analysis and atomic absorption spectrophotometry, and qualitatively identified with scanning electron microscopy and atomic force microscopy. Gunshot residue is collected using carbon-coated adhesive stubs or alcohol swabs, with stubs having fewer false negatives. Firing distance can be determined using tests like the Greiss test, which can help identify homicide versus suicide or entrance versus exit wounds. Each gunshot residue case must be individually evaluated as test results alone do

1. Topic -Gun shot residue
By- Jagrati Sharma
To- Ketan Sir

2. CONTENTS
.What is gun shot residue?
.Appearances of gun powder
.Detection of gun shot residue
.Collection of gun shot residue
.Distance
.Conclusion

5. It is principally composed of
burnt and unburnt particles
from the explosive primer, the
propellant and possibly
fragments of the bullet,
cartridge case, and the
firearm.

6. Degressive (regressive)
burning: gunpowder grains
formed in flakes, balls, and
sticks have a burning surface
area that decreases
continuously as the grains are
consumed.
Neutral burning: gunpowder
grains that are single perforated
and the burning surface area
remains relatively constant.

7. Progressive burning:
gunpowder grains that are multi-
perforated and rosettes that
have a burning surface area that
increases continuously as the
grains are consumed.

8. DETECTION OF GUNSHOT RESIDUE
The major methods for detection of primer residues are
analytical and qualitative. Analytical methods include
neutron activation analysis (NAA) as well as atomic
absorption spectrophotometry (AAS) and inductively
coupled plasma mass spectroscopy (ICP-MS). Scanning
electron microscopy with energy dispersive analysis by
x-ray detector (SEM-EDX) and atomic force microscopy
(AFM) are used to identify the primer residue
qualitatively.

9. COLLECTION
The method of collection for residue is quite simple
and easily carried out in the field. The two widely
used methods include collection onto a carbon-
coated adhesive stub or with an alcohol swab. Of the
two, the stub has fewer false negatives from greater
collection efficiency. The swab method may have
usefulness when the surface to be tested is smooth,
or if propellant analysis is required.

10. DISTANCE
Firing distance determination is a common factor in
investigations. Saferstein (2006) states that using
the Greiss Test method provides a more contrasted
view of GSR on a surface. DiMaio (1999) states
that using Greiss Test results can help determine
whether a case is a homicide or a suicide. Brazeau
and Wong (1997) say that using GSR tests can
also help determine whether a bullet wound is an
entrance or an exit wound.

11. CONCLUSION
There are no two cases that are completely
and indisputably the same. That is why each
case has to be looked at individually.
Investigators need to take the time to
evaluate the results of any tests and
evidence, including gunshot residue.

12. Just because a gunshot
residue comes back
negative does not
necessarily mean there
was never and residue
there.

13. The same goes for a
positive result, just because
a test comes back positive
does not necessarily mean
that that person was the
shooter or held the gun.

14. THANK YOU