I just started reloading for the first time last week and am having a bit of a issue. After full length resizing my once fired winchester brass it chambers fine but the bolt is very stiff to close.I also bought some new remington brass and it works great.I reloaded the remington brass 3 times thinking it might do the same with stiff bolt but every time it is fine.What would be the reason for this as I am doing everything the exact same with both brands.

check the lengh of the resized brass, and the lengh of the finished round, be sure both are in spec, i'd start there,

Sounds like the Winchester brass may have stretched beyond OAL max.. Check and see.

the length of resized brass and finished round are the exact same in both rounds.I am reloading for .243 case length after resized and cut are 2.035 and finished are 2.655.

Screw the sizing die down on the shell holder till it contacts it with the ram in the fully "up" positon. Lower the ram. Screw the die down in tiny increments till the ram begins to "cam over".

Size a case and see if it fits the chamber.

If it does with a slight "crush fit" you're good.

If it won't chamber without force, screw the die down a little more and repeat

Sounds like you need to bump the shoulder a little.

Try sizing your WW brass, then retact the press ram and spin the case 1/2 turn without pulling it over the expander ball. Then size again slowly and let the ram dwell at the top of the stroke for a few seconds. If that works your die needs to be set slightly lower.

Yup!! I'd guess either they need trimming - which I really doubt. Or, the shoulder needs to be set back a skosh. I'd suggest rcamuglia's solution. I don't think your die is properly adjusted.
Bear in Fairbanks