Reddit reviews M1x12 Viton O-Ring, 75A Shore Durometer, Round, Black, 12 mm ID, 14 mm OD, 1 mm Width (Pack of 25)
We found 2 Reddit comments about M1x12 Viton O-Ring, 75A Shore Durometer, Round, Black, 12 mm ID, 14 mm OD, 1 mm Width (Pack of 25). Here are the top ones, ranked by their Reddit score.
Metric O-ring made of Viton (fluorocarbon elastomer) for use with a variety of chemicals and fuelsDurometer (hardness) of 75A for resistance to penetrationRound cross-section provides a seal between cylindrical overlapping surfacesFor use across a wide temperature range from -15 degrees F/-26 degrees C to 400 degrees F/205 degrees CMeets standards defined by Aerospace Standard AS568A
If you don't take out the booster assembly on a regular basis, a drop or two of rocksett on those threads will keep it from backing out on you. Also, when you tighten the can on to the host, be aware that on a LH threaded barrel like your SIG, you want to make sure you "snap" the can tight and then leave it, because if you sit there and bear down on the thing to tighten it more you're then applying torque that will loosen the threads between the booster assembly and the tube.
Since you're using a SIG factory barrel, the piston will index on the muzzle face, and not on the thread shoulder. You can run a small viton O-ring at the rear of the threads which will hold the can in place and keep it from un-threading. The thread spec on those barrels is designed for this purpose. IIRC an M1x12 will fit properly, like these: https://www.amazon.com/gp/product/B005RUP2Q0/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1
I use these. I bought a couple packs in case they go missing. http://www.amazon.com/M1x12-Viton-Ring-Shore-Durometer/dp/B005RUP2Q0?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_search_detailpage