Hi @MiniLuxy
I have the original TM buffer tube and it was still too tight. It does move but not as freely as you would like. The original TM buffer has at least 1mm clearance and in other areas more.
It is only the exterior of the end cap that needed some mass removing but it didn’t take long. With a decent diamond file I took the required material off. Cleaned it off and tested it until it moved freely.
Once there was enough material off I used 240 grit sandpaper to smooth it. Then 600 to get it smoother still. I then moved to wet and dry with a little gun oil starting at 1000 grit, then 1500 grit, then 2000 grit, finishing with 2500. Make sure to clean off the buffer in between sand papers.
It took some time but was worth it. If you don’t feel confident and you can get it to me, I’ll do it for you, I live in Nottingham.
If you are happy to do it yourself and want a little more guidance, I’m happy to help with any information you need.
Cheers
Sean