DO NOT POST/VOTE IF YOU ARE STUPID OR DON'T KNOW WHAT YOU ARE TALKING ABOUT. I DO NOT WANT TO KNOW ABOUT YOUR FRIEND WHO BUILT A SUPER-LEET SNIPER RIFLE, I WANT TO KNOW ABOUT YOUR BUILD! When you vote, PLEASE post an explanation or info. OK, so here's the issue. I finished my DMR gearbox, and having not even assembled the gun yet, I can tell that there is an airseal issue because the air output from the GB is not even as high as my RPK. I am running a full stroke M190 with double bearings. My air-seal components are SOLID. -Guarder clone PHEAD -Home depot stretched heated #14 o-ring -Chromed stock cylinder -Gasketed lonex cylinder head -SHS aluminum nozzle with o-ring -M190 style reaps bucking -Metal hopup unit I can do a full airseal test, pressing the piston as hard as I can, and there is no leak. It is sealed great with 100% silicone. But when I dry-fire the gearbox, the air strength is very very low. Not enough to move a piston body more than a few inches along the ground. All my other air-seal components are literally worryproof, the nozzle seals perfectly on the cylinder head, the cylinder head has double orings AND permatex. So the issue, it seems, like any other DMR build, is the piston head o-ring. So what works for you? For my RS SVD, I used silicone gear grease and it worked better then 100% silicone oil, so I'm thinking I should use that. Please give me your knowledgeable opinion.