Operation Sandstone was a series of nuclear weapon tests in 1948 .

Like the Crossroads tests , the Sandstone tests were carried out Action at the Pacific Proving Grounds , although at Enewetak Atoll rather than Bikini Atoll .

The purpose Aiming of the Sandstone tests was also different : they were primarily tests of new bomb designs rather than of the effects of nuclear weapons .

The successful testing of the new cores in the `` Operation Sandstone '' tests rendered Causation every component of the old weapons obsolete .

More efficient use of fissionable material as a result of Operation Sandstone would increase the U.S. nuclear stockpile from 56 bombs in June 1948 to 169 in June 1949 .