These 17-4 H900 booster pistons are in the pattern we have coined as BPISTIN, a homophonic acronym which stands for:
Booster Piston, Industry Standard Ten Index Notch
They will fit:
-All ECCO Machine booster assemblies and pistol suppressors
-All SilencerCo booster assemblies and pistol suppressors except Osprey models
-Rugged Obsidian 9 & 45
-Dead Air Odessa
-OSS Rad 9 & 45
-Current YHM booster assembly
IMPORTANT! Most pistons have two options in each size. The first with no designation besides the thread size will be THROUGH-THREADED. These are meant to register on a shoulder behind the threads, which needs to be at least .050″ larger than the thread diameter for proper alignment and retention. The second option will be denoted in the dropdown with thread size followed by “MR” (ex, 1/2-28 MR) indicating MUZZLE REGISTER; muzzle register pistons have an internal shelf at a depth of .43″/11mm, and are the correct choice for barrels with no shoulder or a shoulder less than .050″ over thread diameter. Muzzle register pistons will work fine on barrels with a shoulder, though there will typically be a visible gap between the shoulder and the back of the piston.
For example, a Beretta 92 has a barrel diameter of .572″, leaving .072″ shoulder with 1/2-28 (.500-28) threads, therefore should use a through-threaded piston. A standard 1911 .45 has a barrel diameter of .578″ with .578-28 threads, meaning there is no shoulder at all and it needs a muzzle register piston.
*Note: Though nearly identical and able to install in Griffin boosters, Griffin pistons have a slightly larger flange, so the BPISTIN pattern will be sloppy in them and may cause detrimental misalignment.
|Piston Thread Pattern||
1/2-28, 1/2-28 MR, 9/16-24, 9/16-24 MR, .578-28, .578-28 MR, 5/8-24, M12x1 MR, M13.5 x1LH MR, M14x1 MR, M16x1 MR, M16x1LH, M16x1LH MR