LBE Unlimited Complete "F" Marked Front Sight Base, Taper Pins, Sight Post, Detent, Spring, Swivel, and Swivel Rivet ARFSB-KIT ARFSBKIT

LBE Unlimited Complete “F”-Marked Front Sight Base Kit — AR-15/M4 | Includes Taper Pins, Sight Post, Detent, Spring, Sling Swivel & Rivet | Model: ARFSB-KIT (ARFSBKIT) | UPC: 706612407830 Restore duty-grade iron sights or build a reliable backup front sight the right way with the LBE Unlimited Complete “F”-Marked Front Sight Base Kit. Purpose-built for modern flat-top AR-15/M4 uppers, this assembly includes the F-marked front sight base, taper pins, front sight post, detent, spring, plus a sling swivel and rivet—everything you need in one, matched package for a clean, professional installation. Why “F”-Marked Matters Flat-top receivers sit slightly higher than legacy A2 carry-handle uppers. An “F”-marked front sight base is engineered to the correct height for these uppers, providing proper mechanical zero and worry-free co-witness with popular red dots and BUIS. Translation: your irons line up the way they should—no chasing elevation or running out of adjustment. Key Features & Benefits True “F”-Marked FSB: Proper front-sight height for most flat-top (A3/A4) AR-15/M4 uppers to achieve correct zero with standard rear sights. Complete Hardware Kit: Includes taper pins, sight post, detent, spring, and sling swivel with rivet—no hunting for small parts. Alloy Steel Construction: Durable, armor-tough build to handle heat, recoil, and round-count abuse. Pinned Security: Taper-pin attachment is the gold standard for robust, repeatable alignment on hard-use carbines. Sling-Ready: Included front sling swivel and rivet make adding a traditional two-point sling fast and tidy. LBE Unlimited Quality: Trusted small-parts supplier known for reliable, mil-style AR components. Compatibility Note: Most FSBs like this are made for .750" barrel journals (the most common size). Please verify your barrel’s gas block journal diameter and pinned vs. set-screw readiness before purchase. What’s in the Kit LBE Unlimited “F”-Marked Front Sight Base 2 × Taper Pins (left-to-right orientation typical) Front Sight Post (standard square) Detent & Spring (front sight elevation) Sling Swivel & Swivel Rivet Ideal Use Cases Flat-Top AR Builds: Ensure correct iron-sight geometry from day one. Duty/Defense Carbines: Pinned FSBs resist shift under heavy use and temperature changes. Backup for Optic-Equipped Rifles: Maintain a dependable mechanical sighting system that co-witnesses cleanly. Retro-Modern Projects: Keep the classic fixed-front silhouette while benefiting from today’s upper heights. Installation Guidance (High-Level) For best results, have a qualified gunsmith handle fitting and pinning. Correct installation typically involves: Confirming barrel journal diameter and gas port alignment Proper FSB indexing to maintain vertical alignment with the receiver Reaming/setting taper pins from the correct side for a secure lock-up Verifying gas seal and function after assembly Safety & Compliance: Always follow federal, state, and local laws. Ensure the rifle is unloaded and remove ammunition from the workspace before any work. After installation, perform a safe function check and sight-in. Performance Advantages You’ll Notice Correct Zero Window: Plenty of adjustment travel without bottoming out the post. Return-to-Zero Durability: Pinned FSBs hold alignment through heat cycles and physical knocks better than most clamp-on options. Consistent Co-Witness: Predictable sight picture with standard rear sights and common optics. Specs (Typical) Type: Front Sight Base, “F”-Marked (AR-15/M4) Attachment: Taper-pinned (pins included) Front Sight Post: Square, elevation adjustable (post, detent, spring included) Sling Interface: Front sling swivel + rivet included Material/Finish: Alloy steel with protective finish (manufacturer standard) Model: ARFSB-KIT / ARFSBKIT UPC: 706612407830 FAQ Q: Will this fit my barrel? A: Most users pair this with .750" journal barrels. Verify your barrel’s journal size and whether it’s machined for pinned gas blocks/sight bases. Q: Do I need special tools? A: Pinning an FSB typically requires proper jigs/fixtures and reamers. For safety and alignment, we recommend professional installation. Q: Is the front sight post standard? A: Yes—standard square post, adjustable for elevation via the included detent and spring using a typical front sight tool. Q: Will it co-witness with my red dot? A: On most flat-top uppers, an F-marked FSB provides the correct height for standard co-witness setups when paired with the appropriate rear sight and mount. Q: Is the sling swivel included? A: Yes. The kit includes the sling swivel and rivet so you can finish the classic front-sling attachment. SEO Highlights (What Shoppers Search For) LBE Unlimited “F”-Marked Front Sight Base Kit ARFSB-KIT / ARFSBKIT complete with taper pins, sight post, detent, spring Front sling swivel and rivet included AR-15/M4 front sight base for flat-top uppers Pinned gas block strength and correct iron-sight height UPC 706612407830 Build with confidence and keep your irons true. The LBE Unlimited Complete “F”-Marked Front Sight Base Kit gives you the right height, the right hardware, and the right durability for a dependable AR sighting system—no guesswork required. "The End"