The Riflespeed .750 adjustable gas block 5.8-inch assembly is a tool-free gas control for AR-15 and AR-10 rifles, built for a gas block journal of .750 inch (Riflespeed model RS7558). A numbered control knob clicks into each setting, so you can turn the gas up or down and return to a known setting later for light commercial ammunition, higher-pressure milspec loads, suppressed shooting or hot and cold weather. At 5.8 inches, this is one of several assembly lengths Riflespeed makes so the control can tuck under extended handguards. The modular plunger design covers .223 Remington and 5.56x45mm, 300 AAC Blackout, .308 Winchester and 7.62 NATO, 6.8 SPC, 6.5 Grendel and other cartridges. It needs a straight gas tube, Riflespeed’s or another maker’s, and the tube is sold separately.

Key Specifications

• The gas block journal diameter is .750 inch, so it fits barrels with a journal of that size.
• The assembly length is 5.8 inches, the dimension to check against your handguard and muzzle device.
• Adjustment is tool-free through a numbered control knob that clicks at each setting, so a setting is easy to read and repeat.
• A rotation stop limits how far the knob turns, which prevents unintentional disassembly while the control still comes apart without tools.
• It requires a straight gas tube, which is sold separately, so plan the tube length for your gas system.

Frequently Asked Questions

Which cartridges does it work with? Riflespeed lists .223 Remington and 5.56x45mm, 300 AAC Blackout, .308 Winchester and 7.62 NATO, 6.8 SPC, 6.5 Grendel and all other cartridges, using the correct plunger size.

Which gas block journal does this model fit? This model is made for a .750-inch gas block journal. Riflespeed also makes gas controls for the other journal sizes it lists, so match the journal on your barrel.

Buy the Riflespeed Adjustable Gas Block, .750-Inch Journal, 5.8-Inch Assembly

Riflespeed built its gas controls to be set once and repeated, so a new load or a suppressor no longer means guessing at the gas. Order it from our Lubbock, Texas gun shop for fast, insured shipping, and see more AR-15 accessories and parts while you are here.