The peepsight makes a cherry on the cake.

First let me say that I love the ironsights of all types, because they represent for themselves a piece of mechanical art, we all miss in todays mass production standards.

But there is an issue in practical use in combination with the common express rear sight, espacially with the standing leave.
If the standing sight is unaltered you have always a rather disturbing semicircular shadow in the lower half of the horizontal throughsight.
Far from beeing perfect (at least in my eyes).

For a clear view and correct aiming, one can help filing down the standing leave or turning the notch into a half moon design ( wide enough not to disturb the throughsight using the diopter ).
This dilemma is in common with all types of peep sights.

One severe problem is connected with the folding down striker nut mounted peepsights.

If you are accustomed to cycle the bolt from the shoulder especially in a hurry for a followup shot you may damage your eye in case the sight is folded down.

That type of sight ads a remarkable length to the bolt especially in the folded down position.
Too much for my taste.

Measures taken on a Parker Hale item ( not very much differing from the Lyman).

In case of a magnum Mauser bolt you can ad 12mm more in length.