I have a question: Which ones did you play around with buffers on???? I'm thinking my rifle set-up almost like this one needs a heavier buffer. I'm running a rifle length gas system, 18" barrel (1 in 7 twist), carbine (ACS) stock. My rifle seems to be working harder than it needs to be/maybe overgassed. I bought a Spikes ST-T2 buffer to throw in it to calm it down a bit. I'm hoping it settles down and still functions 100%...
The gun that was the most problematic & that I was working with the most was gun #3 with the 16" Rise barrel with a mid-length gas system.
The barrel has a larger than typical gas port by quite a bit, .091" vs a typical mid-length at around .080" so it was very much originally overgassed as I expected it would be.
I originally installed a fixed Viltor gas block as it was on hand & available, & I expected to be able to use a heavier buffer to get it near where I want it to be. As I originally tested it, I used an H buffer & a Sprinco Blue (enhanced spring) & ejection was forward at 1 o'clock & the brass was pretty heavily dented from hitting the rear of the ejection port & the very front of the deflector.
Going to an H3 buffer did very little to help so I removed the fixed gas block & installed an adjustable gas block & re-tested with the H buffer & Blue spring & with the gas adjusted properly, all was good. I also tested with an H2 buffer & liked it better so that's how I've left it. Ejection is 3:00 to 4:30 depending on ammo, no dings & it seems to just be touching the very rear of the deflector & no failures to lock back with any ammo.
It's a pretty light & short barrel, in a fairly light gun, but the recoil & sharpness of the gun is now greatly improved.
It's generally my practice to use an adjustable gas block for flexibility, & in this case, that practice was just further validated.
Gun #2, the 18", also a mid-length gas barrel (but with a .083" port) was done from the git-go with an adjustable gas block & the Spikes ST-T2 buffer / standard weight Sprinco White spring & with some fine tuning to the gas block, it's been perfect. The ST-T2 is between an H & an H2 buffer in weight.
My own view of the world is to not go too heavy on the spring as getting carried away with spring weight leads to more likelihood of bolt bounce on the return bolt closure.
Maybe Blue or Yondering or WE700 or Rost might offer their insights................but an adjustable gas block just makes life much, much easier in the end.
The KAC 18" rifle gas gun has a non-adjustable gas block from KAC but it has run perfectly from day one with (from them) a carbine buffer & whatever spring they are using.............KAC knows WTF they are doing. I actually have 2 more of their guns that are 16" CL barreled guns with their proprietary intermediate gas systems & they all run perfectly with a carbine buffer & the stock spring......................I've seen no reason to change the way that any of them came from the factory. If I ever decide to change anything, it would be to put on an adjustable gas block, but so far, there has been no need.
