The first element is significant. It says that lawful business or personal use is a valid reason for a multiple-handgun purchase. Why is there a comma following that element if it is not the first element in the list? Would you write "There are,
one, two, three, four and five" or would you write "There are one, two, three, four and five?"
In a list of items the last comma before the last element is optional. It doesn't matter if it's there or not. Eg. "one, two, three, four, and five;" "one, two, three, four and five;" and "one, two, three, four, five" are all grammatically correct and have the same meaning.
The sentence fragment in question is "for lawful business or personal use, in a collector series, for collections, as a bulk purchase from estate sales and for similar purposes."
I don't need to change anything. Take the comma that I put at the end of 4) and it's still a separate element. That sentence right there is plain English and the five bullets I listed are the five elements in the list.
If the word 'for' were removed from element 5), then one could argue that 4) and 5) would not be separate elements. Eg. "[...] as a bulk purchase from estate sales and similar purposes" could be one element. Eg. "[...] as a bulk purchase from estate sales and for similar purposes" are two elements in a five element list. Further, if 4) and 5) were intended to be one element it should have been phrased "[...] as a bulk purchase from estate and similar sales." It doesn't say "similar sales" as you say. It says "similar purposes," which further separates it from the preceding element. The last element in the list, "similar purposes," is a catch-all to include any purposes similar to the preceding four elements.