$32.89
13 in stock
Online inventory may differ from in-store availability.
Quick turnaround so you get your gear sooner.
Trusted checkout with industry-standard protection.
Keeping Traditions Alive Since 1953
Secure Transactions provided with 
Anyone who has spent time behind a real A1 upper knows the rear sight has one annoying quirk: adjusting windage means digging for a bullet tip or that little A1/A2 combo tool just to turn the tiny knob. Luth-AR fixed that problem with this Modern A1 Rear Base Sight Assembly. It keeps the low-profile, fixed-elevation A1 silhouette that a lot of builders want for a retro-style rifle, but swaps the stock windage knob for their Rapidex knob, which is sized and knurled so you can turn it by hand. No more fumbling for a tool or chewing up a cartridge tip mid-range session.
The original A1 design was built to be tamper resistant, which is great for keeping a zero locked in but a pain when you actually need to make a correction. The Rapidex knob solves that by giving you a knob you can grip and spin with your fingers, so quick windage corrections at the bench or between strings of fire don't turn into a whole production. It still holds adjustments just as securely once you're dialed in, it just doesn't fight you to get there.
This rear base sight assembly is built for AR-15 platform rifles running an A1-pattern upper, whether that's a retro build, a budget carbine, or a rifle where you just prefer the slimmer sight profile over the bulkier A2 carry handle setup. It bolts in using the standard roll pin and detent hardware, so if you've ever installed an A1 or A2 rear sight before, this one goes together the same way.
Each unit includes the rear sight base, the flip aperture, the windage knob screw, the Rapidex windage adjustment knob itself, along with the detent, detent spring, and roll pin needed to mount it. It's a complete rear sight assembly rather than just a knob upgrade, so there's nothing extra to source before you can get it installed and zeroed.
Whether you're finishing out a retro-style build, replacing a worn or damaged factory sight, or just tired of hunting for a tool every time you need to adjust windage, this assembly gets you back to a proper A1 sight picture with a much friendlier adjustment experience.
A standard A1 rear sight needs a bullet tip or a special combo tool to turn the tiny windage knob, which gets old fast when you're trying to zero at the range. The Rapidex knob on this Modern A1 Rear Base Sight Assembly is shaped and sized so you can grip and turn it with your fingers instead. You still get the same click adjustments and secure hold once it's set, just without the tool hassle.
No, this is a true A1-style sight, which means elevation is fixed and gets set through the front sight post rather than a rear elevation drum like an A2 sight has. If you want a dial-up elevation knob on the rear sight, you'd want an A2 or A3 style assembly instead. This one is built for shooters who prefer the slimmer, simpler A1 sight profile.
This assembly is designed to fit AR-15 uppers machined for an A1-pattern rear sight, which is common on retro-style builds and some flat-top uppers with a removable carry handle setup. It installs using the same roll pin and detent method as a factory A1 sight, so if your upper currently runs an A1 sight, this will be a direct swap.
It's a full rear sight assembly, not just a knob. You get the sight base, the flip aperture, the windage screw, the Rapidex knob, and the small detent hardware needed to mount it, so there's nothing else to buy separately to get it installed.
If you've ever swapped out an A1 or A2 rear sight before, the process here is the same, using the roll pin and detent to secure the base to the upper receiver. It's a manageable job for someone comfortable doing basic AR-15 parts work with the right punch and hammer, though a gunsmith can knock it out quickly if you'd rather not deal with roll pins.
Some shooters just prefer the lower profile and simpler look of an A1 sight, especially on retro or lightweight builds where the bulkier A2 elevation drum feels unnecessary. Since elevation is handled at the front sight post, the rear stays cleaner and less prone to getting bumped out of adjustment. It comes down to personal preference and the style of build you're going for.
| UPC | 812058032335 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | UR-21M |
You must be logged in to post a review.
Reviews
There are no reviews yet.