NVG Mounting — Wilcox L4 vs Ops-Core VAS

If your helmet program involves optics — PVS-14, PVS-31, GPNVG-18, any NVG — shroud compatibility is a bigger decision than most procurement RFPs treat it as. Get it wrong and you're buying adapter plates or custom machining.

The two dominant shroud systems

Wilcox L4 series: the legacy standard. Metal shroud, robust, ubiquitous. Most MICH-pattern and legacy FAST helmets pre-drill for Wilcox L4 G24 or G35. Uses a J-arm or dovetail mount for NVG attachment.

Ops-Core VAS (Visual Augmentation System): newer, lighter, integrated with the broader Ops-Core / Gentex accessory ecosystem. Native on FAST SF and newer Ops-Core shells. Uses a different mechanical interface than Wilcox.

They are not interchangeable without an adapter.

Shroud-to-helmet compatibility

Most helmet shells pre-drill for one or the other. Some manufacturers offer multiple drilling patterns:

Team Wendy EXFIL — Wilcox L4-compatible drilling by default
Ops-Core FAST SF — VAS native
Galvion Batlskin — configurable at order
3M Ceradyne ACH variants — typically Wilcox-compatible

If you're procuring a helmet and you already own NVG + J-arm inventory, match the shroud to the existing inventory. Replacing a fleet of J-arms to change shroud systems is expensive.

J-arm and dovetail — the NVG side

The shroud on the helmet is half the system. The NVG needs a corresponding mount — either:

J-arm — the classic angled arm; most PVS-14 and PVS-31 inventory ships with J-arm mounting
Dovetail — a flatter, more secure interface used on newer Wilcox G35 and GPNVG-18 rigs
VAS bridge — for GPNVG / dual-tube setups that need bridge mounting

Match the J-arm or dovetail to the shroud. A PVS-14 with a J-arm does not mount directly to an Ops-Core VAS shroud without an adapter.

Counter-weight

NVG mounted forward requires counter-weight aft. Forward-heavy helmet balance fatigues the wearer fast and drives forward head-posture during extended wear. Most SOCOM NVG-using operators run a rear counterweight pouch (Team Wendy CAM-Fit Counterweight, Ops-Core CB-3) with battery or lead weights.

RFP language for an NVG-integrated helmet procurement should require a compatible counter-weight system as part of the shell package, not as an accessory order.

What to specify in an RFP

For agencies planning NVG integration on day one:

"Helmet shall be pre-drilled for [Wilcox L4 G24 / Ops-Core VAS] NVG shroud. Vendor shall supply matching shroud pre-installed. Vendor shall supply compatible counter-weight pouch. Vendor shall certify compatibility with agency's existing [J-arm / dovetail / VAS bridge] NVG mounting inventory."

For agencies that may add NVG downstream:

"Helmet shall be pre-drilled for a shroud system compatible with both Wilcox L4 and Ops-Core VAS retrofit (via vendor-supplied adapter plate or native drilling). Vendor shall provide documentation of shroud retrofit process."

The second option costs less at helmet purchase but more at NVG add-on time.

Rails — the other side of the accessory story

Modern helmets also include rail systems for comms, lights, and cameras. ARC rails (Ops-Core) and Wilcox rails dominate; Team Wendy has its own EXFIL rail. Rails are independent of the NVG shroud decision but typically come from the same ecosystem vendor.