Arisaka Tailcp Adp Protac R Mnt Hl-X

The Arisaka Tailcap Adapter for Protac Rail Mount HL-X lights is a purpose-built solution for shooters who want to run Streamlight's compact rail-mounted light with Surefire's proven Scout-pattern tailcap ecosystem. If you're already invested in Surefire remote switches or need compatibility with tactical accessories like the SR-D-IT or TAPS dual switches, this adapter bridges the gap—letting you mate a Protac HL-X to the tail-control systems and switching options that Streamlight never designed into their original light.

One of the biggest headaches with Protac Rail Mount lights is battery rattle under recoil. Because Streamlight omitted a front battery spring, your CR123 or 18650 cell can drift backward when you're shooting, causing intermittent flicker or dropout. Arisaka addressed this by including two sized o-rings—one for CR123, one for 18650—that you install on the battery's rear end before threading on the adapter. The o-ring locks the battery in place and eliminates that unreliable behavior entirely. It's a simple fix to a real problem, and it's why this adapter has earned respect among shooters running serious optics and pressure switches on short rails.

Built from 6061-T651 aluminum and MIL-A-8625 Type III hard coat anodized, the adapter is compact and durable. Note that you'll need to supply your own Surefire UE or DS tailcap—the adapter itself is just the middle piece—and compatibility is limited to the Protac Rail Mount HL-X (not the newer Protac 2.0 line or the HL-X Laser variant).

Key Features

• Adapts Streamlight Protac Rail Mount HL-X to Surefire Scout-pattern tailcaps and remote switches
• Includes two o-rings (CR123 and 18650 sizes) to eliminate battery rattle under recoil
• CNC machined 6061-T651 aluminum, hard coat anodized for durability
• Enables use with Surefire SR-D-IT and TAPS dual switches for laser/illuminator setups
• Made in the USA

Specifications

Frequently Asked Questions

Does this adapter work with the Protac 2.0 Rail Mount or the HL-X Laser version?

No. The Arisaka Tailcap Adapter is compatible with the Protac Rail Mount HL-X only. It does not work with Protac 2.0 lights or the Rail Mount HL-X Laser model.

What tailcap do I need to use this adapter?

You'll need to supply a Surefire UE or DS tailcap separately. The adapter connects your Protac HL-X to Surefire's Scout-pattern switching system, but you must source the tailcap yourself.

How do the included o-rings prevent battery rattle?

Install one o-ring on the rear end of your battery (use the CR123 size for those cells, the 18650 size for rechargeable batteries) before threading the adapter onto the light. The o-ring acts as a stop, preventing the battery from sliding backward under recoil and causing flickering.

Can I use this with laser and illuminator systems?

Yes. Once adapted with a Surefire tailcap, your Protac HL-X becomes compatible with Surefire remote switches like the SR-D-IT and TAPS dual switches, which are often paired with laser/illuminators such as the ATPIAL and DBAL series.