I've always been looking for realism but in the end, a gas gun simply isn't reliable as a DMR in a country with a cold climate due to the inconsistent FPS. I therefore look switch from GBBR to build an AEG-based variant instead. The picture shows a concept of how I want the gun, a G&G Knight's Armament SR25 E2 APC M-LOK, to look when the build is finished.
I have never worked with AEGs before other than switching from a plastic to a metal receiver on a CYMA AK, so I have absolutely no idea what I am doing and I wish to not ruin a brand new 600€ Rifle - Yes, That is it's cheapest price where I live.
I'm looking to make the gearbox as quiet as possible with a quick trigger response and clocking the FPS around 425. People I have talked to mention "Gearbox Shimming". I have no idea how this is done or how hard it is.
Finally, Since I'll be running a CTR Stock I wish to know if there are Ni-MH batteries that are small enough to fit in the buffer tube as I'd prefer Ni-MH over LiPo due to their ability to be stored with 100% Charge. If I need to use a LiPo battery after all I would like some tips on safety because I clearly remember the day a teammate's stock suddenly turned into a smoke grenade and then proceeded to be on fire for the following 2 minutes.