The time of the mussaf prayer

Is there a problem to recite the mussaf prayer later? We want to take a long break between Torah reading and mussaf.

Ab initio, the mussaf prayer should be recited before the time of minchah gedolah, which is a half an hour after noon (all the times are halachic). The reason for this is that one should recite one’s prayers in the order of shacharis – mussaf – minchah; however, once the time for minchah has arrived, it now has to be recited first, before mussaf. Nevertheless, someone in this situation is not yet considered a transgressor. If one recited mussaf after the seventh hour (one hour after noon), though, one is considered a transgressor. Despite this, it is still possible to recite this prayer until nightfall.

Therefore, ab initio, the mussaf prayer should not be scheduled any later than minchah gdolah, and for sure not after the seventh hour of the day. In addition to that, you should know, that if the time of minchah gdolah (half an hour after noon) has arrived, then the minchah prayer has to be recited first, and then the mussaf prayer has to be recited immediately afterwards.  

Shulchan Oruch, section Orach Chaim, chapter 286, §1; Mishnah Berurah, ibid., subsection 3; Biur Halachah ibid.