Most likely. H4895 is a very versatile powder in that burn rate range and can be safely loaded down quite a ways as well. If your chosen powder was too slow you would most likely see unburnt powder in your barrel and have a pretty decent fireball. In a 20" I am betting you are just fine and can start working up to find your max if you wish.
FWIW I have a 16" 250AI barrel that I load with RL22 under 120gr Interlocks and I get good accuracy and mild recoil and no noticeable fireball.
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