New Rifle Scope Reticle Perpendicularity
I have recently acquired a SAKO TRG-22 in .308. I am temporarily putting a Nikon Monarch III scope on it and I am trying to set it up for long range shooting/learning. I have been studying how to mount the scope myself so that the scope is "true to bore". I have found several techniques that seem to make sense.
After leveling the gun in a vise and following the procedure, I am now "true to bore". Now, when I choose to go to the range and do some practice, how am I to insure that the rifle is always level during practical shooting? I would typically be shooting prone on a mounted bipod. Is it common for someone to have a level on their rifle when shooting to insure the shot is on axis? Or will any tilt in the overall rifle still end with like results because it is "true"? Imagine this being done in perfect conditions without any other contributing factors.
Sorry if I am ignorant, I am trying to learn.