The US Army procured T48 rifles from three firms for testing, including two U.S. based companies in an effort to assess the manufacturability of the FN design domestically.

The T48 was manufactured for testing by Fabrique Nationale (FN), of Herstal, Belgium; Harrington & Richardson (H&R) of Worcester, Massachusetts; and the High Standard Company of Hartford, Connecticut.

[2][3] FN engineers opened the gas ports in an attempt to improve functioning, but this caused early/violent extraction and broken parts as a result of the increased pressures.

[2] In the end, the T44 was selected over the T48/FAL primarily because of weight (the T44 was a pound lighter than the T48), simplicity (the T44 had fewer parts), the T44's self-compensating gas system, and the argument that the T44 could be manufactured on existing machinery built for the M1 rifle (a concept that later turned out to be unworkable).

On January 22, 2025, Palmetto State Armory, current owner of the intellectual property including trade-marks of Harrington and Richardson, announced the introduction of a new production run of the T48 rifle for the US civilian market.