Bisley HETO42C Two-Piece Extended High Scope Mount
The Bisley HETO42C is a two-piece extended, high dovetail scope mount designed for 25mm (1in) scope tubes. It fits the 9.5-11.5mm dovetail rails commonly found on rimfire and airgun actions.
The extended design positions the rings further forward, providing increased eye relief for scopes requiring the objective lens to be set back. The high ring height clears large-bell scopes with an objective lens up to 56mm in diameter.
| Specification | Detail |
|---|---|
| Scope Tube Diameter | 25mm (1in) |
| Dovetail Rail Fit | 9.5–11.5mm |
| Ring Height | High (clears up to 56mm objective lens) |
| Mount Type | Two-piece extended |
| Securing Mechanism | Four bolts and clamps; two-bolt base with removable stop pin |
FAQ
What makes the HETO42C different from standard scope mounts?
The HETO42C features an extended design that moves the rings forward for greater eye relief and a high ring height that clears large-bell scopes with objective lenses up to 56mm in diameter.
Can this mount be used on all rimfire and airgun actions?
Yes, it fits actions with 9.5–11.5mm dovetail rails, which are standard on most rimfire and airgun rifles.
Is the stop pin included and how does it work?
Yes, the removable stop pin is included and keys into the rail’s recoil slot to prevent the mount from shifting under recoil.

John Kerr –
Fitted the mount to my airgun without issues. The eye relief is much better than with standard rings, and the large objective lens fits perfectly without touching the action. Easy to install and stays secure during shooting.
Joan Welch –
Works well with my 56mm bell scope. The high ring height clears the lens completely, and the stop pin keeps it stable during recoil. A bit more complex to assemble than standard mounts, but worth it for the performance.
Brandon Pullman –
Great for long-range airgun shooting. The forward ring position gives me more comfort and reduces eye strain. Solid build quality and fits my rifle perfectly.