Good luck on your hunt, where are you going? I live in Alberta and have gone out many times with a bow and rifle after bar' and in Saskatchewan we used to shoot them as nusance animal. There was so many that a resident did not have to buy a tag.
Yes the bears are smaller in the spring due to consuming a lot of their fat reserves over the winter. A book bear can loose around 150+ pounds by spring. What ever you choose make sure it is a heavier load for your rifle. Bears have small vitals and big bones and don't go after them with something that you would not take after a Large Moose or Elk.
The bugs will be crazy so make sure that you have some sent free bug dope with you and start looking at bears now any way you can. A decent shooter will stand as tall as a 55 gal drum and the ears will be wide apart on the sides of his head. If you have to think about wheather or not a bear is big it probably isn't. When you see a big bear you will know that his is the one, you won't have to ask yourself if he is big.
Having tracked large bears on my hands and knees through the willows in schmangla (thick crap) after a one lung shot with a bow, is not my idea of fun family entertainment. Though it does rank up on the excitment level.[

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Have a good hunt
Eric