Primary Arms SLx Cantilever 30mm Scope Mount

The Primary Arms SLx Cantilever 30mm Scope Mount is a one-piece cantilever mount for 30mm-tube scopes, built to hold zero through hard use at a price that undercuts the premium names. The cantilever design pushes the rings forward so you can position a 30mm LPVO or variable scope correctly for eye relief on an AR-pattern rifle, where the receiver would otherwise force the scope too far back. It sets your optic at a 1.5" optical centerline, the standard height for a co-witness-friendly AR setup.

Where it earns its keep is the clamping system. A three-bolt cross-bolt design distributes recoil evenly and generates over 6,500 lbs of clamping force, and it's backed by dual machined recoil lugs plus three cross-bolt lugs. That combination lets the mount shrug off heavy recoil and sustained fire without shifting your zero, which is the one thing a scope mount absolutely has to do. It's machined from 6061 aluminum with steel hardware and a hardcoat anodized finish, so it's tough without being heavy at 5.785 oz, and it carries Primary Arms' lifetime warranty.

This is the 30mm version, for scopes with a 30mm main tube (check your scope's tube diameter, it's a different mount than the 34mm). If you want to add an offset red dot for fast close-range transitions, it pairs with the matching SLx 30mm Top Cap Reflex Mount, which sits a 507C-footprint dot at the 12 o'clock position above your scope. Browse the rest of our optics and mounts here.

30mm or 34mm?

Match the mount to your scope's tube diameter. This 30mm version fits 30mm-tube scopes; if your scope has a 34mm tube (common on higher-end LPVOs and long-range optics), you need the SLx Cantilever 34mm Mount instead. The tube size is usually printed on the scope or in its spec sheet.

Add an Offset Red Dot

The SLx 30mm Top Cap Reflex Mount bolts onto this mount and holds a mini reflex sight above your scope for a quick close-range aiming option. It fits the popular Holosun 507C footprint, so dots like the Holosun 507C or 407C drop right on.

Key Features

• One-piece cantilever. Correct scope placement and eye relief on AR-pattern rifles.
• 1.5" optical centerline. Standard co-witness-friendly height.
• Three-bolt clamp. Over 6,500 lbs of clamping force, evenly distributed.
• Dual recoil lugs. Plus three cross-bolt lugs to resist recoil and hold zero.
• Tough and light. 6061 aluminum, steel hardware, hardcoat anodized, 5.785 oz.
• Lifetime warranty. Backed by Primary Arms.

Specs

• Type: One-piece cantilever scope mount
• Ring size: 30mm
• Optical centerline: 1.5"
• Cant: 0 MOA
• Clamping force: Over 6,500 lbs (three-bolt design)
• Recoil lugs: Dual machined recoil lugs + 3 cross-bolt lugs
• Material: 6061 aluminum, steel hardware
• Finish: Hardcoat anodized, black
• Rail: MIL-STD-1913 Picatinny
• Ring torque: 16–18 in-lbs
• Base torque: 30–35 in-lbs
• Weight: 5.785 oz
• Warranty: Primary Arms lifetime

FAQ

Will this fit my scope?
It fits scopes with a 30mm main tube. Check your scope's tube diameter (printed on the scope or in its specs). If it's 34mm, you need the SLx Cantilever 34mm mount instead.

Why a cantilever mount?
On AR-pattern rifles, the receiver sits the scope too far back for proper eye relief. A cantilever mount pushes the rings forward so you can position the scope correctly, which is why cantilever mounts are the standard choice for LPVOs and variable scopes on ARs.

Will it hold zero?
Yes. The three-bolt clamp delivers over 6,500 lbs of clamping force, and dual recoil lugs plus three cross-bolt lugs keep it locked to the rail through heavy recoil and sustained fire without shifting zero.

Can I add a red dot?
Yes. The matching SLx 30mm Top Cap Reflex Mount bolts on top and holds a 507C-footprint mini reflex sight above the scope for fast close-range transitions.