check the oal ,after resizing the case may be to long.
Turn you resizing die in 1/8 of a turn untill you set the sholder back just enough to chamber the cartrage.

even after trimming the bolt closes very very tight
Thanks

Try marking the fired case at the top as it comes from the chamber.....before the case is extracted and check to see if the fired case will go into the chamber easier if the mark is at 12oclock or 6 oclock and similar directions......make sure the extractor is not hanging up on the rim or barrel....I had a gun with misfitted extractor that hit the action before the extractor could fit over the case rim and it acted similar to what you are gettting.......if the different directions of the marked spot make a difference in the action closing.....then you need to do a chamber cast or similar to check for a "egg shaped" chamber....if that is the case then the only fix is a new barrel ...good luck and good shooting!!

I really need some help
Winchester Model 70 Super Shadow .243 WSSm
Factory Amunition diameter at the bottom of the case is 0.550 after shooting it and removing it from my rifle it measures .555 the shoulder befor is .540 and after is .547
Then when i go to put it back in the rifle before or after resizing it is very hard to close the bolt.What the heck is going on here? did they not ream my chamber to the proper specks or what am i missing? Any help would be great.
Thanks
CdnWalleye