Especially when it’s on a TM advert , as the mongtard selling it has more than likely bolloxed it so that even if it’s working ok now you know sometime in the near future there is an implosion just waiting for you ! There’s a reason TM are still regarded as the benchmark for reliability without needing basically to do ANYTHING to your gun . There built for the Japanese market and the Japanese don’t really give a flying fornication about what the rest of the world wants , the Japanese just don’t go in for all the ‘upgrading’ bullshitery , they just want out of the box total reliability end of and that’s how TM design there guns so once you do start pissing about with them you just knock the thing out of sink and what started as a ‘simple’ spring replacement to up the FPS (because we all know only FPS matters !🤦♂️) suddenly becomes near a total gear box ‘upgrade’. 😳