Backup Iron Sights (BUIS):
Backup Iron Sights (BUIS) are rifle sights (front and rear) that are designed to be used in the event of a failure with the primary optic. These sights are typically designed to fold down while not in use to prevent obstructing a functional primary optic. When needed, the front and rear backup sights are flipped up.
Despite the name, backup iron sights are typically made of steel, aluminum, plastic, or various combinations of those materials.
It should be noted that many users prefer to equip their rifles with this type of front and rear sight only. In this case, the flip-up sights become the primary sighting solution, rather than just a backup.
Sidenote: Backup Iron Sights, Back-Up Iron Sights, and Back Up Iron Sights are all commonly used spellings.
Midwest Industries Combat Rifle Sight Set (Shown Above):
- MI-CRS-SET
- Includes: Combat Rifle Front Sight #MI-CRS-F, Combat Rifle Rear Sight #MI-CRS-F, MI A2 Front Sight Tool #MI-A2ST
- For AR15/M4/M16 Rifles and other platform
- MI Combat Rifle Front Sight
- Low Profile .437″ when folded down, flips up to Mil-Spec sight height
- Uses standard A2 front sight post
- Dual locking detent springs for added reliability and crisp positioning
- Constructed of ordnance grade phosphate finished steel
- Hardcoated 6061 aluminum base
- 1.5 MOA per click adjustments
- Weight 1.4oz
- MI Combat Rifle Rear Sight
- Super low profile .388″ centerline when folded down
- Flips up to Mil-Spec height
- Intermediate aperture for long-range precision and close-range rapid engagement
- Dual locking detent springs for added reliability and crisp positioning
- Constructed of phosphate finished ordnance grade steel
- Hard coated 6061 aluminum base
- Rifle .5 MOA / Carbine .65 MOA click adjustments
- Weight 1.2oz
- 100% Made in the U.S.A.