Luth-Ar Gt-Cup Grovtec Base/Cup

The Luth-AR GT-Cup GrovTec Base/Cup is a quick-detach sling attachment point built for Luth-AR modular buttstocks. If you run an MBA-series buttstock on your rifle, this cup provides a robust, proven way to mount QD sling swivels without drilling or modification. It threads directly into the existing side cup holes found on MBA-1, MBA-2, MBA-3, and MBA-4 stocks—each buttstock features a mounting location on both sides of the frame, giving you flexibility to set up your sling configuration exactly how you want it.

GrovTec has long been the standard for reliable sling hardware in the AR and modern rifle world. This cup maintains that reputation: it's a simple, mechanical solution that doesn't rely on proprietary systems or complicated installation. You can thread it in with a standard 1/4" Allen wrench (or use a separate installation tool if you prefer). Once seated, it provides a solid, non-rotating anchor for your QD swivel—meaning your sling stays put and doesn't twist under load.

Whether you're setting up a duty rifle, a hunting gun, or a precision build on an MBA platform, this cup solves the common problem of needing multiple sling attachment points without adding bulk or weight. It's especially useful if you like to run a single-point sling and want the option to swap to two-point, or if you simply want symmetrical mounting on both sides of the stock.

Key Features

• Threaded design fits all MBA-series Luth-AR buttstocks (MBA-1, MBA-2, MBA-3, MBA-4)
• Accepts standard QD (quick-detach) sling swivels
• Two mounting locations per buttstock—one on each side of the frame
• Installation requires only a 1/4" Allen wrench
• Robust GrovTec quality and proven reliability

Frequently Asked Questions

Will this work with my Luth-AR buttstock?

The GT-Cup is compatible with all Luth-AR MBA-series buttstocks: MBA-1, MBA-2, MBA-3, and MBA-4. Each stock has side cup holes on both the left and right sides of the frame, so you can mount one cup on either side or both.

What sling hardware do I need?

The cup accepts standard quick-detach (QD) sling swivels. You'll need a separate QD swivel to complete the attachment—the cup is the mounting base only.

What tools do I need to install it?

Installation is straightforward: you can thread the cup in using a standard 1/4" Allen wrench. Alternatively, a separate GrovTec installation tool is available if you prefer a dedicated tool.

Can I install one cup or do I need both sides?

You can install the GT-Cup on one side or both—it's your choice depending on your sling setup and shooting preferences.