
Availability: In Stock
The Grovtec GTHM308 hammer extension transforms your Marlin 36 or Marlin 336 lever-action into a faster, more intuitive gun to manipulate in the field. This black steel clamp-on accessory adds a serrated horizontal lever to your hammer spur, giving you a wider, more graspable surface where your thumb needs it most. Whether you're shooting through a low-mounted scope, bundled up in heavy gloves, or working a rifle under pressure in wet conditions, the broader grip point makes cocking faster and more confident without fumbling.
The design keeps the extension hollow to avoid adding unnecessary weight to the hammer itself—meaning no degradation to locktime or hammer speed. Installation is straightforward: the extension clamps securely to either side of the hammer using a steel Allen head screw, so you can position it wherever feels natural for your shooting style. Once seated, it holds tight and won't shift during the shooting day.
This is a no-nonsense upgrade for hunters and shooters who log miles with vintage Marlins and want better ergonomics without aftermarket stock modifications or gunsmithing. It's especially valuable if you're running an optic on a lever gun and need your hammer spur to stay out of your sight picture, or if you simply want more control when working the hammer in less-than-ideal conditions.
| Brand | Grovtec US Inc |
| Model | GTHM308 |
| Finish | Black Steel |
| Compatibility | Marlin 36 (1936–1947), Marlin 336 (1948–1956) |
| Fastener | Steel Allen head screw |
| Type | Clamp-on hammer extension |
The Grovtec GTHM308 is designed for Marlin 36 rifles manufactured between 1936 and 1947, and Marlin 336 rifles produced from 1948 through 1956.
Yes. The clamp-on design allows you to position the extension on either side of the hammer spur, so you can set it up to match your dominant hand and shooting style.
No. The extension is hollow, which keeps it lightweight and prevents any negative impact on hammer speed or locktime performance.
The extension fastens with a steel Allen head screw, so you'll need an Allen wrench (hex key) to tighten it securely to your hammer.



SKU: 115649286 • Width: 4.6in • Height: 1.5in • Depth: 5.3in • Weight: 0.06oz





Availability: In Stock
The Grovtec GTHM308 hammer extension transforms your Marlin 36 or Marlin 336 lever-action into a faster, more intuitive gun to manipulate in the field. This black steel clamp-on accessory adds a serrated horizontal lever to your hammer spur, giving you a wider, more graspable surface where your thumb needs it most. Whether you're shooting through a low-mounted scope, bundled up in heavy gloves, or working a rifle under pressure in wet conditions, the broader grip point makes cocking faster and more confident without fumbling.
The design keeps the extension hollow to avoid adding unnecessary weight to the hammer itself—meaning no degradation to locktime or hammer speed. Installation is straightforward: the extension clamps securely to either side of the hammer using a steel Allen head screw, so you can position it wherever feels natural for your shooting style. Once seated, it holds tight and won't shift during the shooting day.
This is a no-nonsense upgrade for hunters and shooters who log miles with vintage Marlins and want better ergonomics without aftermarket stock modifications or gunsmithing. It's especially valuable if you're running an optic on a lever gun and need your hammer spur to stay out of your sight picture, or if you simply want more control when working the hammer in less-than-ideal conditions.
| Brand | Grovtec US Inc |
| Model | GTHM308 |
| Finish | Black Steel |
| Compatibility | Marlin 36 (1936–1947), Marlin 336 (1948–1956) |
| Fastener | Steel Allen head screw |
| Type | Clamp-on hammer extension |
The Grovtec GTHM308 is designed for Marlin 36 rifles manufactured between 1936 and 1947, and Marlin 336 rifles produced from 1948 through 1956.
Yes. The clamp-on design allows you to position the extension on either side of the hammer spur, so you can set it up to match your dominant hand and shooting style.
No. The extension is hollow, which keeps it lightweight and prevents any negative impact on hammer speed or locktime performance.
The extension fastens with a steel Allen head screw, so you'll need an Allen wrench (hex key) to tighten it securely to your hammer.
SKU: 115649286 • Width: 4.6in • Height: 1.5in • Depth: 5.3in • Weight: 0.06oz


