Colt M4 Carbine vs SIG SAUER M400
Data coverage: Based on 510 agencies in the Duty Arms Index with a current, sourced rifle entry. Generations and optic-cut variants are combined per model family. Counts include only current entries with a public source; agencies not yet in the index, or without a sourced entry for this item, are not counted, so treat shares as a picture of the Duty Arms Index, not of every U.S. agency. Data last updated Oct 10, 2026.
Colt M4 Carbine
5.56x45mm / .223
- Agencies (any current entry)
- 52
- As primary issue
- 26
10.2% of 510 agencies with a sourced entry in this category.
M4 shown with M68 (Aimpoint) optic. Photo: Photo Courtesy of PEO Soldier, Public domain, via Wikimedia Commons. Model photo, not the agency's own firearm.
SIG SAUER M400
5.56x45mm / .223
- Agencies (any current entry)
- 14
- As primary issue
- 9
2.7% of 510 agencies with a sourced entry in this category.
Representative photo: SIG M400-series rifle (Commons category SIG Sauer SIGM400) carried by an Iraqi counter-terrorism trainee, U.S. Army photo; not a U.S. agency's rifle. Photo: Pfc. Anthony Zendejas, U.S. Army, Public domain, via Wikimedia Commons (cropped). Model photo, not the agency's own firearm.