Alphabetic Index FY2027

W33.1

Accidental rifle, shotgun and larger firearm malfunction

FY2027Chapter 20: External causes of morbidity/W20–W49 Exposure to inanimate mechanical forces

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

W33.1 is a non-billable ICD-10-CM code header for accidental rifle, shotgun and larger firearm malfunction. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are W33.10 Accidental malfunction of unspecified larger firearm, W33.11 Accidental malfunction of shotgun, W33.12 Accidental malfunction of hunting rifle, W33.13 Accidental malfunction of machine gun and 1 more. Its coding notes include 12 Excludes1 entries.

7th characters

Every code below needs one of these (defined at W33).

The appropriate 7th character is to be added to each code from category W33

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

An external cause code is never a principal or first-listed diagnosis. Its 7th character is assigned for each encounter and should match the injury or condition code.

Guidelines I.C.20.a.2; I.C.20.a.6External cause codesRead the official text

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from W33 Accidental rifle, shotgun and larger firearm discharge and malfunction
  • accidental airgun discharge and malfunction (W34.010, W34.110)
  • accidental BB gun discharge and malfunction (W34.010, W34.110)
  • accidental handgun discharge and malfunction (W32.-)
  • accidental pellet gun discharge and malfunction (W34.010, W34.110)
  • assault by rifle, shotgun and larger firearm discharge (X94)
  • firearm discharge involving legal intervention (Y35.0-)
  • firearm discharge involving military or war operations (Y36.4-)
  • intentional self-harm by rifle, shotgun and larger firearm discharge (X73)
Also from chapter/block level (4 notes)
Inherited from W20–W49 Exposure to inanimate mechanical forces
  • assault (X92-Y09)
  • contact or collision with animals or persons (W50-W64)
  • exposure to inanimate mechanical forces involving military or war operations (Y36.-, Y37.-)
  • intentional self-harm (X71-X83)

Includes

Further defines or gives examples of the content of the category.

Inherited from W33 Accidental rifle, shotgun and larger firearm discharge and malfunction
  • rifle, shotgun and larger firearm discharge and malfunction NOS

Inclusion terms

Conditions classified to this code.

This code
  • Injury due to explosion of rifle, shotgun and larger firearm (parts)
  • Injury due to malfunction of mechanism or component of rifle, shotgun and larger firearm
  • Injury due to piercing, cutting, crushing or pinching due to (by) slide trigger mechanism, scope or other gun part
  • Injury due to recoil of rifle, shotgun and larger firearm
  • Powder burn from rifle, shotgun and larger firearm

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 20 External causes of morbidity
  • This chapter permits the classification of environmental events and circumstances as the cause of injury, and other adverse effects. Where a code from this section is applicable, it is intended that it shall be used secondary to a code from another chapter of the Classification indicating the nature of the condition. Most often, the condition will be classifiable to Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88). Other conditions that may be stated to be due to external causes are classified in Chapters I to XVIII. For these conditions, codes from Chapter 20 should be used to provide additional information as to the cause of the condition.

More specific codes under W33.1 5