I have a new unfired DPMS SASS 308 semi auto rifle. I'd like to install an adjustable gas block for running the rilfe suppressed and unsuppressed. How do I determine which adjustable gas block to install?
- Thread starter felix5616
- Start date
Either slr 9 or jp low pro .936 will suit you just fine.
thanks mheimer_45, how difficult is it to install for a novice? i love shooting, hate tinkering
The Superlative Arms gas blocks are also excellent, if you can find any in stock. These gas blocks are specifically designed with suppressed shooting in mind.
Gas blocks come in several standard diameters, depending on your barrel profile. They are the same for 5.56 and .308 ARs:
- 0.625" (pencil barrels, typically AR15 only)
- 0.750" (standard barrels)
- 0.875" (heavy barrels)
- 0.936" (heavy / bull barrels)
You'll have to measure your barrel's gas block journal diameter, the region of the barrel where the gas block sits. The gas block journal is usually a bit longer than the gas block, and extends in front of it. So, you *should* be able to measure the gas block journal diameter without removing the gas block itself, but you'll probably have to remove the handguard. The DPMS SASS handguard mounts to the barrel nut with a lock ring, which this video shows how to remove.
Also, make sure that your new gas block is able to fit under your handguard. Some large-diameter clamp-on gas blocks are too big to fit under some handguards. The manufacturer will sometimes show a schematic of the gas block on their website for this exact reason (Superlative Arms and SLR Rifleworks do).
Installation is straightforward. You can follow this video.
You will need a few tools:
- Calipers, for measuring the gas block journal.
- Spanner wrench, for the DPMS handguard
- 5/64" roll pin punch, for the gas tube roll pin
- Small hammer, for the gas tube roll pin
- Inch-pound torque wrench adjustable to 20-40 in-lbs, for the gas block set screws
- Feeler gauges in the 0.020" - 0.030" range, for aligning the gas block front-to-back
- Vise, to hold the barrel or upper receiver (optional)
- Vise blocks / reaction rod, to hold the upper receiver (optional)
- High temperature thread locker. The video uses red Loctite, but I use high-temperature blue Loctite 2422 for easier removal.
It is definitely tinkering, but no more technically involved than working on a bicycle.
Gas blocks come in several standard diameters, depending on your barrel profile. They are the same for 5.56 and .308 ARs:
- 0.625" (pencil barrels, typically AR15 only)
- 0.750" (standard barrels)
- 0.875" (heavy barrels)
- 0.936" (heavy / bull barrels)
You'll have to measure your barrel's gas block journal diameter, the region of the barrel where the gas block sits. The gas block journal is usually a bit longer than the gas block, and extends in front of it. So, you *should* be able to measure the gas block journal diameter without removing the gas block itself, but you'll probably have to remove the handguard. The DPMS SASS handguard mounts to the barrel nut with a lock ring, which this video shows how to remove.
Also, make sure that your new gas block is able to fit under your handguard. Some large-diameter clamp-on gas blocks are too big to fit under some handguards. The manufacturer will sometimes show a schematic of the gas block on their website for this exact reason (Superlative Arms and SLR Rifleworks do).
Installation is straightforward. You can follow this video.
You will need a few tools:
- Calipers, for measuring the gas block journal.
- Spanner wrench, for the DPMS handguard
- 5/64" roll pin punch, for the gas tube roll pin
- Small hammer, for the gas tube roll pin
- Inch-pound torque wrench adjustable to 20-40 in-lbs, for the gas block set screws
- Feeler gauges in the 0.020" - 0.030" range, for aligning the gas block front-to-back
- Vise, to hold the barrel or upper receiver (optional)
- Vise blocks / reaction rod, to hold the upper receiver (optional)
- High temperature thread locker. The video uses red Loctite, but I use high-temperature blue Loctite 2422 for easier removal.
It is definitely tinkering, but no more technically involved than working on a bicycle.
Thank you nutation for taking the time to provide such in depth references, very much appreciated
