Originally Posted by ithaca_deerslayer
Wow, I hadn't known that. Reliability is certainly something I want. What type of gas issues are dissipators known for?
Proximity of the gas port to the muzzle can lead to issues with the bolt unlocking too early (going from memory here, and I'm not fully awake yet, please forgive me if I'm wrong), which leads to extraction and feed issues. Some ran fine with a properly sized gas port and just the right carrier and buffer. Some were picky about ammo, and some ran like ass.
This is why someone came up with the mock dissipator - all the looks and advantages, but without the issues that comes with running a rifle gas system on a 16" barrel. On an 18-20" barrel, rifle gas systems should run just fine. It's only an issue on the 16" guns.