Optic-Cut Holsters Explained: Do You Need an RMR Cut for Your Carry Gun?

A few years ago, putting a red dot on an everyday carry gun was considered niche. It was something competitive shooters did, or gear nerds who didn't mind sending their factory slide off to a machine shop for six weeks to get milled.

That isn't the world we live in anymore.

Walk into any gun shop today and try to find a modern carry pistol that doesn't come with an optic-ready slide straight from the factory. Glock MOS, Sig Sauer P365X, Springfield Hellcat, Canik MC9—optics cuts are practically standard equipment now.

Naturally, holster designs had to catch up. But if you’re shopping for a new Kydex holster, you’ve probably run into the dropdown menus asking whether you need an "optic cut" or "RMR cut."

If you aren't running a red dot yet, do you still need an optic-cut holster? What happens if you get one anyway? And why does half the industry still act like cutting a little clearance out of the sweat shield deserves an extra $15 charge?

Let's break down how optic cuts actually work, why your holster's geometry matters, and what you actually need for your carry setup.

What Actually Is an "Optic Cut"?

In simple terms, an optic cut (sometimes labeled an RMR cut because the Trijicon RMR set the early standard) means the holster shell is molded and trimmed with clearance right in front of the rear sight.

On an old-school, full-coverage holster, the Kydex wraps high up over the sides of the slide. If you try to jam a pistol with a mounted dot like a Holosun 407k or Trijicon RMR into one of those older shells, the plastic will hit the front face of the optic housing before the gun ever seats around the trigger guard.

An optic cut drops the front and side profile of the holster mouth just enough so that the dot can clear completely without rubbing, binding, or blocking the gun from locking into place.

"What If I Only Shoot Iron Sights Right Now?"

This is hands-down one of the most common questions we get through the shop email:

"I'm carrying factory iron sights today, but I might buy an optic in six months. Can I use an optic-ready holster with bare irons?"

Yes. Absolutely.

A common misconception is that a Kydex holster relies on the top of the slide to keep the gun secure. It doesn't.

Quality Kydex holsters get their retention by snapping into specific retention grooves, usually around the trigger guard on a standard gun, or around the bezel and body of a weapon-mounted light. The slide channel and the optic area are mostly just along for the ride.

Whether your slide has a red dot mounted to it or just standard factory three-dot irons, the gun clicks into the trigger guard exactly the same way. The retention is identical and the draw is unchanged.

If you don't have an optic today, buying an optic-cut holster hurts nothing. But buying a non-optic holster means that the day you decide to mount an EPS Carry or an RMR, you're stuck buying an entirely new holster—or sitting in your garage with a Dremel tool trying not to butcher your gear.

Why We Don't Upcharge for Optic Cuts

Here’s a little behind-the-scenes shop reality: trimming an optic clearance on a modern CNC router or vacuum-form mold adds essentially zero material cost.

Yet, if you look across the holster industry, plenty of companies still treat an optic cut like a luxury add-on. You build your holster in their cart, hit the "Optic Cut: Yes" radio button, and watch another $10 or $15 get tacked on for the privilege of them removing a quarter-inch of plastic.

It made sense eight years ago when red dots were rare and shops had to hand-dremel one-off clearance profiles on custom molds. It makes zero sense today.

That’s why on our entire lineup—from the AREN ONE and AREN LITE to the AREN ELITE and our A2 OWB rigs—every single holster comes optic-ready by default at no extra charge.

We cut them low enough to clear practically every major micro and full-size footprint on the market (RMR, Shield RMSc, Holosun K-series, Aimpoint Acro, etc.), and we leave them cut that way out of the box. If you run a dot, it drops right in. If you run irons, it works just as cleanly. No nickel-and-diming, no extra dropdowns to click.

What Else Matters When Running an Optic?

Getting an optic cut isn't the only thing you need to check if you're building out an optic-ready carry gun. A couple of other small geometry details make a massive difference:

1. Suppressor-Height Sight Clearance

When you run a red dot, you often run taller iron sights so you can cowitness through the optic window if the battery ever dies.

If your holster has an optic cut but features a shallow sight channel, those tall backup sights will snag on the plastic inside the tunnel every time you pull the trigger on a draw stroke. All of our AREN series and A2 series holsters are formed with built-in clearance for tall sights (up to .35"), so your backup sights slide freely without dragging.

2. Sweat Shield Height

The sweat shield is the piece of Kydex on the body side of the holster that sits between the pistol slide and your skin.

• Full Sweat Shield: Covers the entire length of the slide up to the rear serrations. Great for keeping sweat off the metal and cold steel off your stomach, but you need to make sure the cut leaves space for the optic hood.

• Mid Sweat Shield: A popular middle ground. It gives you body separation while staying well clear of both the optic glass and your shooting grip.

If you carry appendix and your red dot sits low against your beltline, pay attention to how your clothing rides around the glass. A clean sweat shield profile keeps the holster from pushing the optic forward into your waistband.

The Verdict

If you're shopping for a new concealed carry holster, don't buy a closed-top, non-optic holster. Even if you're a die-hard iron sight shooter today, you gain nothing by closing off that slide clearance. An optic-ready cut gives you room to grow without changing how the holster locks onto your belt or secures your pistol.

Check out the AREN ONE if you want a straightforward, no-nonsense IWB setup, or the AREN ELITE if you're in need of a dedicated appendix rig with lots of adjustability. Regardless of setup, both come pre-cut for optics, support for supressor height sights, and lock in tight whether you've got a dot mounted or not.

Are you running an optic on your daily carry yet, or are you sticking to standard irons? Drop a comment below and let us know what you're shooting.