.357 is non prohibited bore. Non prohibited or prohibited bore has nothing to do with the ballistics of the weapon. The basic criteria is central government's ammunition should not fire in civilian owned firearms. This non prohibited and prohibited bore idea was started by the British around Lord Curzon's time. There was fear that mutiny like of 1857 may repeat. In order to ensure that ammunition looted from central government armories should not fire in civilian population's firearms. Unfortunately the same idea continues today by the central government that (falsely?) claims we got independence(really?) on 15.08.1947, and thus are free people and not slaves of the rulers.
@K T Following are the options to buy .357 -
1. You are residing in some foreign country where .357 is available and then decide to transfer your residence to India. Then you can bring .357 along with 50 cartridges via transfer of residency route. If you are unable to show them arms license, the firearm and cartridges will be confiscated by the Customs. Once you are able to show them the arms license, they will release the confiscated firearm and cartridges.
2. If you are in India and are willing to spend around Rs. 35 to 40 lakhs(Rs 3.5 to 4 million ) to buy from someone who already has .357 with him.
3. You are able to convince the central government to make changes in the import policy of the Directorate General of Foreign Trade.
4. You are able to convince any High Court or Supreme Court that Section 10(1)(a) of Arms Act 1959 is a legal right flowing from liberty of Article 21. This import restriction is without application of mind, is very unreasonable,
ultra vires of Articles 14 and 21 of the Constitution, that is why it is violation of Section 10(1)(a) of Arms Act 1959 when read together with Sections 11A(a), 11(2)(u) and 11G of Customs Act 1962. Section 10(1)(a) of Arms Act 1959, Sections 11(2)(u ) and 11G of Customs Act 1962 are legal rights flowing from equality before law under Article 14 and liberty of Article 21, thus they need to be read into for interpreting to the widest possible amplitude. Since Arms Act 1959 is specific legislation for arms and ammunition, that is why explanation of firearms in Section 48 of Customs Act 1962 gives overriding primacy to Arms Act 1959. Thus to satisfy Articles 14 and 21, Sections 11A(a), 11(2)(u) and 11G of Customs Act 1962, 10(1)(a) of Arms Act 1959 will override the import policy. Because Articles 14 and 21 are violated that is why it is also violation of Competition Act by providing monopolistic abuse by Indian Ordnance Factory, and thus the central government has no jurisdiction to bring your
non commercial import under licensing. Please note the words non commercial import. I have explained this in another thread(here
viewtopic.php?f=4&t=25102) in paragraphs numbered 8, 23, 27, 29, 168 and 179 read together. The links in another post may also be of interest to you, here is the link
viewtopic.php?f=4&t=20173&p=252083#p252083
If you are unable to do any of the above four things then either forget the idea or take an escapist approach to emigrate as suggested by some members. If you face some other similar problem in the new country, will you again take an escapist route and emigrate to another country? That is why I think escapism is not a proper option or idea in this matter.