For those unfamiliar with shooting using iron sights, the transition from using an optic to using the BUIS system can mean having to learn some new shooting techniques and strategies.
Learning how to sight in using iron sights requires comfort in focusing in on the target and the sight, allowing the rest of the field of vision to fade and blur. It also means learning how to sight in the sights, which is both a science and an art.
Placement of the BUIS in the correct location on the weapon will be critical. When the front and rear sight are too close together, there is a loss of depth of field, which means a greater risk of inaccuracy with the shot. As a general statement, the longer the sight radius, or the distance between the front and rear sight, the greater the ability to correctly align the sights and hit the target, particularly with a long-distance shot.
It is important to also have the rear sight, either as a fixed or flip-up sight, closer to the eye than further down the barrel. When the rear sight is too far down the barrel, it is difficult to get proper alignment of the sights, resulting in missed targets and a lot of frustration.
Similarly, having the front sight correctly aligned will be critical. After all, it is the front sight alignment with the target that is the essential factor in accuracy, with the rear sight used to bring the front sight into the rough center of the rear sight, without the need to be perfectly centered.
For those wanting to combine iron sights with scopes on weapons, the flip up sights, as opposed to fixed sights, are always an important option. This allows the BUIS to remain in the correct place and correctly sighted in on the weapon, but out of the way when the scope is in use.