Well I do got quit easily, after turning the case necks I then annealed them this reduced the neck tension. Wait for it still hard extraction ok back to the think tank. I then had an Einstein moment, I would anneal the case body below the shoulder, well I did 2 stopping the colour running 3/8 above the rim so as not to soften the web area. Well that should sort it right ? well no 1 was slightly easier to extract the other was not. Ok think again, necks are sorted at 10th internal case capacity is not the problem my normal load is 36.5g of H335. I will load 2 cartridges of 33, 34 & 35 grains and shoot them over my chronograph. Start with 33 gr (2348 fps), stiff extraction it should have fallen out ? Never mind the 34 gr load try the 35gr (2415 fps). Hard extraction, just as another check I divided the 2415 fps by 35gr and multiplied by my normal 36.5 gr charge giving me a theoretical velocity of 2518fps. The actual load runs at 2507fps. So the velocity obtained was in line with the powder charge ? at no time did any primer show any signs of excessive pressure.
Conclusion the brass is just to hard and does not shrink back after firing as it should, it will be going back to the supplier accompanied by Mr Grumpy.
Solution I have ordered 100 Nosler cases from Brownells UK, and have cleaned and primed my Norma brass to be loaded later tonight. The Winchester brass did very well but was getting well past its sell by date. If anybody has any ideas please chip in, Gar.