S400 barrel band
I removed the barrel band from my MPR, which is a slightly thicker heavier barrel. But i would stongley advise you to fit a Rowan barrel sleeve which pushes up to the breech block and then grub screws to the barrel, this will firm up the barrel considerably. Mick Trowmans made a large nylon washer for the gap between the filler cap and the cylinder to tidy things up, the whole thing works perfectly. Nothing lost if you think it's not right, just put together as it was. Give it a go.
Even if you think your on the right road, you'll get run over if you just sit there.