Tuning for slugs. Unconventional methods?

This is what happened with my RedWolf with Fx slug liner A. 

I was shooting some samples from H&N and I had and 23 and 26g NSA slugs. They were shooting ok and I must admit then I was happy. I thought the accuracy was typical for shooting slugs. I then made 2 changes to the gun. I sleeved the slug liner in carbon fibre and changed the air stripper. When I next shot slugs I was trying different ones and got to the 26g nsa .217 and at 80m they were almost landing on top of each other. I had to keep shooting because at first I thought I’d had a few lucky shots. They kept hitting the same spot. I don’t no which change I made caused this and the power level was identical to before. 

It has made me think that when shooting slugs maybe we should include a few other means of tuning like barrel bands and weight. Perhaps an adjustable air stripper like Rowan Engineering make. 

To tinker with the harmonics as well as fps reg pressure ect. Maybe we’re not looking in all the right places? 
 
Interesting. So I am guessing the three spacers we have on the Crown Cont. in the 700mm superlight barrel housing also would aid in tuning harmonics. I placed mine in the same spots as they came off the pallet liner, but I am going to play around with this next week.

I would bet that if I pushed all three of them closer to the muzzle the vibrations on that end would likely tighten up a bit, not sure if that is good or bad, but can definitely see that it might have an impact.