I recently bought a Ruger Ar556 MPR in .223 and absolutely love it. However, I would like to upgrade and get another upper for it dedicated to deer hunting. I almost never have a shot over 150 yards and usually hunt in thick areas. I mostly am looking for something to handle shooting into light brush if needed. I have basically narrowed it to 300 blackout, 6.5 grendel, 6.8 sp and 450 bushmaster. Im leaning towards the grendel and blackout. I love how little the .223 kicks and want to stay as close to that as possible but am willing to budge on that for performance. I have looked at pretty much all of the ballistics of the calibers but no one ever talks about capabilities in the brush. I want to be able to shoot through a few small branches and not have to worry about it. I have no experience with any of these calibers. Obviously cheaper ammo is better but i wont be plinking with it so thats not a big deal. I will be buying a whole new upper for whatever i bought. Any thoughts? Thanks in advance.