just been out today and sited in my tikka properly , so i thought i would let you know the results. winchester 50 gr,s 3/4 inch group with 5 shots .very pleased with this ,had a bit of spare time so i tryed the federal 55 gr,s which i had the problems with ;2 1/2 inch group which was better than the original 4 inch group. so it goes to show the problem was with the heavier bullets, but it also shows that cleaning the barrel has helped to .going to try and get some 40 gr,s next and see how these shoot,i will keep you all informed .