Here's the numbers for the field office in Puerto Rico - Why don't you let us know  what you find out -

I checked with the BATF field office in Puerto Rico as suggested. They said there was no federal regulation against shipping magazines to PR. They also said that the gun laws there were very strict and the police could intercept you shipment and charge the recipient. At their discretion they can consider guns, gun parts, magazines and ammunition as firearms. The posession of firearms are limited to those individuals who posess a license and pay a fee. All others go to jail. They suggested if you must ship a magazine to PR ship it to a Licensed FFL dealer to be safe.

that bites and as a part of the USA I seriously doubt the consituational basis of it all, but then when did that ever enter into the process either

as a part of the USA I seriously doubt the constitutional basis

Puerto Rico is not "part of the USA."  It is a technically independent "Commonwealth," which accepts military protection and other benefits from the USA and whose residents are US citizens by virtue of US law (they aren't "born in the USA" and they aren't really naturalized, either).  The internal government was established in 1900 and the citizenship was conferred by the Jones Act in 1917.

The US has "territories," and "trusteeships" and a few outright "possessions," but Puerto Rico isn't any of those things.  Its status is unique and while in many ways it acts as a state would, it's not a state; it's not a nation, either.  It's a..."Commonwealth."  They have jurisdiction over their internal affairs and domestic policy, while the US has jurisdiction over PR's foreign policy and defenses.  In the Good Old Days of colonialism, this would have been called a "Protectorate," but it isn't quite that, either.

From Wikipedia:

The definition of "Commonwealth" according to current US State department policy (as codified in the department's Foreign Affairs Manual) reads: "The term 'Commonwealth' does not describe or provide for any specific political status or relationship. It has, for example, been applied to both states and territories. When used in connection with areas under U.S. sovereignty that are not states, the term broadly describes an area that is self-governing under a constitution of its adoption and whose right of self-government will not be unilaterally withdrawn by Congress". There are currently two United States insular areas classified with the status of commonwealth, the Northern Mariana Islands and Puerto Rico.

It would be a very interesting court case--unlikely to come to pass--whether the Second Amendment (or indeed, any of the others) applies to PR.  PR has its own Constitution, adopted in 1952, and it's debatable whether ours applies to them at all: probably not.

We acquired the island in 1898 when we took it from the Spanish after the end of the war.  The USA has never been a colonialist nation and our period of "empire building" was brief and abortive.  We handed back Cuba to the Cubans in 1901, the Philippines to the Filipinos in 1946, and PR acquired its Commonwealth status in 1949.  It was (and still is) an important naval base and a significant part of the defenses of the Panama Canal.  Even though we handed back the Canal to the Panamanians during the Carter Administration, the Canal is still vital to US interests and we maintain a naval presence in PR for that reason.  It was easier (and cheaper) to create this "Commonwealth" arrangement than to actually run it as a territory.

A lot of Puerto Ricans would like the island to become a state: at least that many want to be totally independent as a nation; and the rest recognize that they have the best of both worlds, especially in that they don't have to pay US income taxes.  As part of the economic support given by their status, US owned companies whose operations are based there also get tax advantages, and bond issued by the Commonwealth pay interest to the bondholders that's not taxed by either the US or state government.  I own a few such bonds and wish I could get more at a reasonable price,  They pay a very high rate of interest and I pay no tax on the income.  Good deal for them and a good deal for me.

Well as I was taught long ago (and to be honest I had not checked recently) it was a territory. But then there is another angle to it all then too because there are others that claim to be commonwealths one of which is Pa.

But none the less in my book either it is part of the US or it ain't but that is how I feel about it rather than how I know about it so it means little all the tech stuff --JMHO is all

But in my book if they are US citizens that is enough for me they ought to get the same rights then---unlike the war prisoners that are not US citizens and get them when they are not due them ----or at least the common press screams for them to the rights