i forgot to mention that i replaced the o-rings. i'll take a look at your thread and see. I didn't taper the cylinder head and I can imagine it's gonna be hard on the new one (it's steel i think...) As for the outer barrel, I drilled the hole in the front of the gun bigger to allow the barrel through it. That was one problem I encountered when first running the longer inner barrel. It was a pain at first, but I eventually got it. The inner barrel runs about halfway through the silencer.