I am new to firearms, and recently purchased my first rifle which is an old m91/30. I have yet to shoot it, and noticed in the barrel the first inch or so is not rifled at all, then the rifling starts and looks good, though a little pitted. is this what they call counterboring? does this affect the performance of the gun at all? I just wanted a rifle that shoots straight as I just started shooting and don't know if I should look for another gun. thanks!