-Your using Chia seeds for ammo?? I've read mixed reviews on that ammo but, haven't tried it myself. Try using a name brand ammo such as "Morton". It should give you a good staring point.
-After that, try moving up to "Himalayan rock salt". But, be careful! You need to either find it pre-crushed to the right size or, go through the process of head sizing every granule. Let me tell you, that's a TIME CONSUMING process!
-As others mentioned, check your scope mounts and screws. Adding a scope level might help your grouping as well. I suspect your scope is good since it still has the "new" stickers on it.
-Lastly, try a different bench rest. The one you're using is known to come from the factory with chipped paint and can cause painful splinters!
Happy shooting!
Tom