if i do the above mentioned with sanding to make it even can i expect any accuracy problems?
To answer your previous question first, there are a number of reasons. Stock warpage is a common cause (laminated stocks are much less prone to warpage), as is poor alignment while machining the barrel channel.
The effect on accuracy is difficult to predict as the current accuracy is unknown. My guess is that if the barrel is touching the stock on one side that you will get horizontal stringing as the barrel heats the wood it contacts. (The same is true for barrels that touch the stock underneath, the result being vertical stringing.) You will also likely get different points of impact with changes in ambient temperature and humidity.
Floating the barrel eliminates these problems. As I said, I float all my barrels, and for just this reason. My first centerfire, a 7mm Rem Mag, proved to be impossible to zero - the longer I shot it the more the POI shifted up and to the left. Floating the barrel fixed the problem.
There is a theoretical downside to floating the barrel, however. While floating keeps the poosition of your groups from shifting, it is possible that group size may increase slightly. On a hunting rifle (which all of mine are), it is much more important to maintain POI than it is to maintain minimum group size. In spite of the theoretical downside, most target and varmint rifles are free floated.
So what has free floating done to my rifles? Week after week, month after month, I am able to go to the range and not rezero my rifles. When I go hunting I don't worry about shifts in POI. Group size, as best I can tell, has not been affected. Here are a few 100 yard examples:
.257 Roberts Ruger M77
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7mm Rem Mag Ruger M77, shot in 40mph crosswind:
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.308 Win Rem M700 BDL
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.30-06 Ruger M77
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.300 Win Mag Ruger M77 MKII (1st shot from an oiled bore)
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