Does it happen with every round, sticking at the same place every time ?

That I think is setback, on the action where the rear lugs contact on close. Or on the lugs.

A sticky bolt from powder is always hard to move when you start opening the bolt, it doesn't start opening easily then stop.

Yes thats it, it open now hassle, then get to last part and stops, some rounds not so bad, but sticky every time. I thought was case length, trimmed, no change. Bump back shoulder, not much difference. Started thinking pressure, but no signs, and velocity is correct and not max.
This set back - tell me more ?

this explains it well

Lug Raceway Setback.

Yes thats it, it open now hassle, then get to last part and stops, some rounds not so bad, but sticky every time.
tell me more ?

Sounds to me very much like a "clicker"
Area at the base near the web is not being sized correctly
The whole reason for the .. ROLLSIZER - which I have described here

See here ,,
die / pressure and clickers

A clicker is a tight case that is stuck in the chamber. The bolt makes a clicking sound when the extraction cam pops the case free. In normal use, your extraction cam is not used.
Most of the time they are caused from an interference fit at the base of the case and chamber. The main cause of this is a sizing die that is oversived in that area. They typically wont show up until 3-5 reloadings of the case.

Clickers...

https://www.youtube.com/watch?v=5oOdQbDq1kE

Until a gunsmith takes it apart and looks at it, you can't be sure this is the problem, its just what came to mind.

There is also the galling of the lugs on the bolt that can look like this

Galled lug.

Galling can happen if sand gets in the action, or can happen simply if there is no lubrication on the lugs.

I always put a dot of copper grease with the end of a toothpick behind each lug every time I clean the rifle.

I will look into this in next 5 minutes

I washed chamber and bolt, definitely feels better in everyway. I have not done more than wipe and drop of oil to the bolt in years. I do not know how this will affect after firing issue, I can not see it helping the original problem - the bolt lifting easy and then stopping. A smart whack lifts it last centimetre and it usually comes back easily then. The case is sticky on extraction, but this is difficult to detect as it does not occur every time.

Why the problem only after firing ?

You have to take it apart and look at it, at least to rule out setback as a problem.

Is it a stainless steel rifle?

What bullet and weight. S335 is faster than S365 and that might be your problem.

Is it a stainless steel rifle?

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Yes

Is it a stainless steel rifle?

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Yes

Some grades of stainless are more prone to galling than regular high carbon steel. I'd inspect the lugs carefully for any sign of discolouration which may indicate galling.

Somchem gives a max load of 52gr for S355. If you use S335 it should be much lower than that. Barrel length would also play a major role.

Yes thats it, it open now hassle, then get to last part and stops, some rounds not so bad, but sticky every time.
tell me more ?

Sounds to me very much like a "clicker"
Area at the base near the web is not being sized correctly

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This is actually more the path of thought I want to follow, all my cases I own are between 3 and 7 reloads. These were 3 when I started reloading again. (This annealing is noticeable in many ways).Come to think of it, I have had this issue with this rifle for since for ever, and seeing it on the .303 now as well. It has however always been a non issue amount of resistance, it has now become a problem amount of force needed I believe it is likely part of my reloading process that is causing it. I neck size, collet size and bump shoulder back only to the minimum. 

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