Thanks for the post. I want to detune my xs28's as you did.I have a pair of used xs28's (.177 &.22).I bought them a year apart as good deals came up.I get almost as good results as yours in terms of accuracy.I bet a tune and a few less spring coils would shrink my groups and make the shooting more fun in general.I am amazed at how accurate both of them are with Walmart Crosman pellets.The .177 is especially accurate with Crosman Domed 10.5's.