The 20" bull or heavy bbl. is a good compromise. At long range, you will never see your bullet impact with the quick jump of the muzzle on a light barrel-especially with the scope dialed up on high magnification. This is even true with the .22 cals., and moreso with larger bores. The longer, heavier barrels stay down with recoil a lot better, even shooting with a bipod attached. Again, it's a personal preference as to what works best for your particular situation.
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