Can you provide sources that discuss the question of a boy who becomes bar mitzvah during sefira. Mostly I have found the question allowing a boy to continue counting with a bracha provided he was successful beforehand. But what if he missed a day as a katan. Does his new status as a Bar Chiyuva allow him to now count again with a bracha. Similarly a ger who converts during sefira. Can he count with a bracha from the day of his geirus?

Shalom, This question is widely discussed amongst the latter day rabbis - and is also a popular subject for Bar Mitzvah drashot (sermons) during the Sefira period. See Rav Ovadya Yosef's Yabiah Omer, volume 3, chapters 15, 27 and 28 for a lengthy analysis, as well as his Yechava Da'at 3,30 for a shorter version. Also see Rav Neuwirth's "Chinuch HaBanim Le'Mitzvot", paragraph 30. And in English the work Shema Beni by Rav Weinberger, chapter 26 discusses the issue very clearly. Many Sephardi rabbis (and some Ashkenazim) rule that the counting of a minor is only of educational value, and not of "really" doing the mitzvah. As such, when he reaches bar mitzvah, even though he counted each day beforehand, his previous count is considered incomplete, and as such he cannot continue to count with a blessing. This is similar to an adult who missed counting a day, who also cannot continue counting with a blessing, as it may be that the mitzvah is dependant on counting all 49 days (but one must continue counting without a blessing, for perhaps each day is an individual mitzvah non-dependant on the other days). Based on this logic the same thing would apply to a convert, even though they had counted every day prior to their conversion. On the other hand, most Ashkenazi rabbis rule that the counting of the child, if no days were missed, should be continued with a blessing after the bar mitzvah. The logic here is that the educational mitzvah of counting before the bar mitzvah counts towards the complete counting of the 49 days. But this is only so if no days were missed beforehand. If days were missed, there is certainly no way to say a blessing, as he is by all accounts missing the full 49. A convert's pre-conversion counting would also seem not be enough of a mitzvah-counting to allow continuing the count with a blessing (Aruch HaShulchan 489,15). Blessings, D.Sperling