This rosary is shot
I probably don't need to point out that eBay is very much a "caveat emptor" (i.e. buyer, beware!) kind of market, and descriptions of anything on eBay should always be taken with several grains of salt. In particular, something said to be "old" or "rare" generally just means that the seller has never seen anything like it and hopes it will be worth money :).
Without seeing this in person, I can't tell exactly how it's made or from what materials, but from the fairly good photos, it certainly does appear to be hand-made, and the round beads look like they could indeed be lead shot. I'm not sure it would have been necessary to melt and re-cast them: it seems to me that boring holes through them would have been easier.
The construction is a simple, common type, with each bead threaded onto a short piece of wire, which is bent into loops at each end. The marker beads (for the Our Fathers) have extra-long wires which are bent double at each end, so that the bead, which is the same size as all the others, is held in the center of the longer wire. This creates a space on either side of these beads. The medal of St. Michael (slaying the devil, a typical pose) looks like a commercial medal that has had new holes bored in it to use as a connector. The reverse of the medal is probably a Guardian Angel (angel shown watching over a child).
The cross is made from more of the round beads, threaded onto two longer pieces of wire, one for the vertical and the other for the crosspiece. The ends are bent over to secure them. As is common with this construction, it's a bit crooked, since the only thing holding the two wires at a right angle is the center bead, which looks as if it has been bored through both horizontally and vertically. It's hard to make a cross that looks good out of two wires and figure out how to join them securely at a right angle, and this has clearly been knocked around a little since it was made. Commercial crosses don't have this problem, since they're cast in one piece.
Finally, the seller says, "This rosary was worn made and worn by a monk and is a penance rosary made to guard against evil to remind him of God's message to take the correct way in his life. Its origin is Austria 1800+s."
That's the kind of story that always makes me skeptical. I don't know how it came into the seller's hands: if it was directly from the person who made it, all of the parts of the story could certainly be true. Otherwise it's nearly impossible to do more than guess when and where it was made, which could have been any century from the 15th to the 21st.
People tend to assume, however, that any large rosary must have been made for a monk or nun to wear on his or her belt -- and that certainly isn't always the case. Large rosaries can also be made as personal keepsakes, or as showpieces, designed to be hung on a wall or provide religious atmosphere to a room, as is often the case with the very large wooden rosaries I discussed a while back in Up Against the Wall. I also think that large rosaries suggest "extra" piety to a lot of people's minds, and so tend to be associated with priests or other "professionally" religious people.
As for the "penance" aspect, well, since it must weigh quite a bit, if someone did wear it around all the time, there might have been some penance involved. But I suspect that's the seller's way of trying to explain a rather awkward object. Catholic artifacts whose purpose isn't obvious seem to attract speculation that they must be "penitential."
I have to share a funny story about one of the rosaries from my own collection. One of the early pieces I made is a 15-decade rosary of rosewood beads, strung on black hemp. I wanted an example of a 15-decade rosary that might have been made by someone of humble origin, and it was also an excuse to display a little one-inch Franciscan "tau" cross (T-shaped) that someone brought me from Assisi years ago. There are also two very worn old medals attached, so worn that you can barely tell what they are, adding to the "old and poor" appearance -- though I shouldn't have cleaned them with metal polish, because you can now read the very un-medieval word "Chicago" on the back of one of them.
When I wear this with medieval clothing, it's usually looped and pinned over one shoulder and across my chest, and tucked into a belt at the other side, so it's rather obvious. Every so often, some would-be-witty good ol' boy with more muscle than brains spots it and says something like, "Gosh, what did YOU do, looks like you have to pray lots extra, hardy har har."
I have a dear friend who is a past mistress of the snappy comeback (I'm not) and she happened to be around for one of these occasions. Afterwards I asked her what I should have said. She told me I should just smile sweetly at the person and say, "Well, but of COURSE. I have to pray for YOU."