Tinck Arms — 3-Position Adjustable Gas Block (MR556 / MR223 / HK416 compatible)

Precision-machined gas block designed to convert MR556 / MR223 rifles to the modern A5-style gas system while offering reliable, tunable performance for both suppressed and unsuppressed use.

Key features

• Hardened steel construction with black Melonite finish for long wear resistance.

• Titanium leaf spring for positive indexing and long service life.

• 3-Position selector:

• N (Normal): Standard ejection-port vent closed for unsuppressed use.
• SS (Semi-Suppressed): For semi-suppressed use.
• FS (Fully-Suppressed): For fully suppressed use.

Three-position — tune perfectly for your suppressor.

• Pre-installed gas vent screw: 1.3 mm (factory installed).

• Additional jet sizes included: 1.1 mm and 1.5 mm – swap quickly to tune gas flow for different barrels, ammo, or suppressor setups.

• Rear-pin retention like the factory HK416 A5 (held by rear pin only).

• Ejection-port side vent with selector cap — easily switched between modes

• Indexing tab: 3 mm width with a 0.75″ profile

Compatibility

• HK416 series

• MR556 / MR223 platforms

• For MR556 A4 you are risking misalignment because the tab is to small

Note: Not intended for use with barrels under 11″, due to interference between the adjustment knob/cap and muzzle device or suppressor. May require barrel/gas port modification.

Listing one-liner
Premium 3-position adjustable gas block — MR556/MR223 & HK416 compatible, 1.3 mm pre-installed jet + 1.1 & 1.5 mm spare jets, N / SS / FS modes, 3 mm indexing tab with 0.75″ profile.