SLR Rifleworks Sentry 7 Adjustable Gas Block

The SLR Rifleworks Sentry 7 is a 15-position side-adjustable click gas block built for AR-15s with .750 inch barrel journals. SLR's metering screw is captive, click-detented, and accessible from the side of the block, which means tuning is a single-tool operation that does not require pulling the handguard. The clamp-on and set-screw variants share the same internals; the clamp-on is the easier install on a non-dimpled barrel, while the set-screw model demands a 1.35 inch minimum inside-diameter handguard like SLR's own Ion or Helix rails to allow tool access through a side cutout.

Internally, the Sentry 7 is a restrictive design: each detent closes off more of the gas port, choking flow into the gas tube. That makes it the right choice for precision and competition guns where you want a known, repeatable setting per ammunition lot. It is less ideal as a dedicated suppressor host gas block than a bleed-off design like the Superlative Arms, because trapped gas still routes back through the action under a can. The 4140 steel body and Melonite QPQ finish handle heat and carbon better than aluminum or unfinished steel, and SLR backs the design with US Patent 9,410,756.

Verified pricing as of 2026 is $148.99 from SLR direct in either clamp-on or set-screw, with the Sentry 8 ($148.99) handling .875 inch journals for ARs that use the larger barrel diameter. The Sentry 7 is the standard pick for the typical 5.56 build with a .750 journal barrel; choose the Sentry 8 only if your barrel measures .875.