The US Army is seeking 12,600 Magpul PMag Gen M3 magazines, or equivalents, from commercial vendors, according to a recently updated listing on FedBizOpps, posted in early August. This announcement was updated soon after the news that Army TACOM had authorized the requisition of Gen M3 PMags with unit funds, by unit commanders

Having said that, the right verb in the opening sentence of this article may be “sought”: Bidding for the solicitation was scheduled to end on the 14th of August, meaning the magazines have likely already been procured. Given the wording of the solicitation, those magazines were almost certainly procured from Magpul themselves:

The MICC End User requires the following items, Brand Name or Equal, to the following:
LI 001: M4 Magazine. Color preference is coyote tan, but gray/black is also considered. Fits 30 rounds of 5.56×45 ammunition. Transparent window on side to see the ammunition level. Strong and durable springs. Light polymer material. Warranty for defective items. Include shipping. PMAG 30 AR/M4 GEN M3 Window or equal., 12600, EA;

According to rifle tests conducted by the US Army in 2015, the M4A1-PMag Gen 3-M855A1 system attained a mean rounds between stoppages (MRBS) of 4,800, over a third higher than the 3,592 MRBS objective for the IC program – a program goal which was criticized at the time by many in the industry as being impossible to achieve.

Although nearly 13,000 magazines may sound like a lot, that is enough for just 1,800 full combat loads, or about 2-3 battalions of men. Since at least some of those magazines are likely intended to be spares, this may mean the magazines are headed for a specific battalion or other large unit, possibly for testing or special application. The exact destination of the magazines is, however, unknown.