What is the best Shofar to use?
The most typical Shofar used for Rosh haShana is the ram's Shofar. Lately, however, the 'antelope shofar' (also known as the 'greater kudu' or 'Yemenite' Shofar, see here ) which is 3 to 4 times longer than a ram's Shofar, became very popular. Probably because it is easier to blow than the ram's Shofar and it has a beautiful 'deeper' sound.
Can we use the 'antelope' Shofar or any other Shofar for Rosh haShana?
An antelope Shofar is perfectly fine to be used for the Selichot of the month of Elul and even for the end of Yom Kippur.
For Rosh haShana, however, using an antelope Shofar or any other Shofar, except a ram's shofar, is a matter of controversy.
The Rabbis discussed the usage of other types of shofar on Rosh haShana, from bovid animals, and explicitly forbade using a cow's horn as a Shofar, because it will remind us of the sin of the golden calf. A ram's Shofar, on the contrary,brings a positive reminiscence: In Rosh haShana we remember aqedat Yitzchaq(the binding of Yitzchaq abinu). Abraham found a ram 'caught in the thicket by its horns', which he then offered it as a sacrifice in place of Yitzchaq.
For some opinions (Maran) it is preferable to use a ram's Shofar in Rosh haShana, and for other Rabbis (Maimonides) the only Shofar that can be blown in Rosh haShana is a ram's Shofar.
In our community, therefore, we would allow using an antelope Shofar on Rosh haShana, only if no ram's Shofar would be available (it never happened yet!).