In the pursuit of accuracy would it be worth stabilising this inner barrel?
This is not mine but a screenshot of the same one from Bradley Phillips SRC SR4 YouTube review
As you can see it would be lucky to have 1mm of movement between the inner and outer.
Also, if its worth doing what would be the best way to go about it, some electrical tape wrapped around the inner?
It’s also worth keeping in mind too that if the barrel is stabilised to the outer too tightly it’s possible that it can shift forward slightly and stay there. That’ll result in a bad airseal.
The spring on your barrel in front of your t-piece is designed to hold it in the correct position relative to the rubber nozzle… if you stick your finger in the magwell you should be able to push your t-piece forward and it should reseat back to it’s home position under spring tension. While it doesn’t really move under fire, if it’s tight it might do with repeated shocks.
A neat but free sliding fit is what you should be trying to achieve.