HOW TO INSTALL AND USE 45-DEGREE (CANTED) BACK-UP IRON SIGHTS ON YOUR RIFLE
Back-up iron sights (BUIS) are a smart addition to any rifle setup, especially as a fail-safe option alongside a primary optic. 45-degree (also called canted) sights are mounted off to the side of the rail so you can simply roll the rifle a few degrees to transition to iron sights without removing or blocking your primary optic. They’re popular among 3-gun shooters and anyone who wants rapid access to backup sighting without obstruction. Below is a quick guide on how to install and use 45-degree BUIS effectively.
STEP 1 — CHOOSE THE RIGHT RAIL AND SIGHT SET
- Picatinny Rail: You need a full-length top rail or at least enough forward rail to mount the rear and front sights.
- 45° Iron Sight Set: These are typically sold as matched pairs. Avoid mixing a 45° front sight from one company with a standard 90° rear from another.
- Correct Height: Verify that the sights are designed for your rail height (such as AR height or gas-block height).
STEP 2 — MOUNT THE REAR (CANTED) SIGHT
- Place the rear sight on the top rail roughly in line with the charging handle on an AR platform.
- Angle the sight so it sits at approximately a 45-degree offset. Most sights are machined for this angle.
- Push the sight forward against the rail slot to remove play.
- Tighten it firmly (do not overtighten). You can leave it slightly loose if you want to make small adjustments after mounting the front sight.
STEP 3 — MOUNT THE FRONT (CANTED) SIGHT
- Install the front canted sight toward the end of the rail to maximize sight radius.
- Confirm that the front sight height matches the rear sight height.
- Push it forward against the rail slot and tighten it down.
- Confirm both sights line up with each other and sit at the same angle relative to the bore.
STEP 4 — ZEROING THE 45-DEGREE BACK-UP SIGHTS
- Choose a normal zero distance (25, 36, or 50 yards is typical for BUIS).
- Roll the rifle about 45 degrees (clockwise for right-handed shooters, counter-clockwise for left-handed).
- Use the windage and elevation adjustments on the sights to zero.
- Fire 3 to 5 rounds, adjust, and repeat until the group is centered.
Important: Zero the sights while actually tilting the rifle. Don’t keep the rifle vertical and just “look through” the offset sights. You want it to reflect how it will be used.
STEP 5 — USING CANTED BUIS IN PRACTICE
- Keep your primary optic up for normal use.
- If the optic fails or you need a clearer view of the target, rotate the rifle approximately 45 degrees by rolling your wrists.
- Your eyes will naturally fall onto the iron sights.
- Practice transitioning from the primary optic to the canted sights and back.
- Try transitions while standing, kneeling, or moving so the motion becomes natural and consistent.
ADVANTAGES OF 45-DEGREE BUIS
- No need to flip up or detach anything
- Does not block red dot or LPVO field of view
- Faster transition than switching to magnifiers or secondary optics
- Adds minimal weight
45-degree iron sights are a smart and efficient backup system, especially for shooters who run a magnified optic or expect to transition quickly between sighting methods. A proper install doesn’t take long—but do take the time to zero them and practice until the tilt transition becomes second nature.