I've just been on to William Hicks who got me started on this GnP buffer thing -
https://www.instagram.com/p/B-YS5wfnIkX/?igshid=xsep5da90p6o
the problem in short was bolt lock could not be achieved because one, I'm a twatt and two, I had the buffer tube wound out far too far as I could not get bolt lock and ended up winding out to far causing the GnP buffer to get stuck - I'm now wound all the way in and it has solved my problem.
He recommends a rubber washer at the bottom of the TM original buffer tube to prevent the rubber on the buffer being chewed up too.
Another point he made to me was check the BCG screws are tight or you can end up like his mate here...
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