test ed . ▁The ▁day ▁after ▁the ▁successful ▁conclusion ▁of ▁this ▁test , ▁Army ▁Chief ▁of ▁Staff ▁General ▁Douglas ▁Mac Ar thur ▁personally ▁disapp ro ved ▁any ▁cal iber ▁change , ▁in ▁part ▁because ▁there ▁were ▁extensive ▁existing ▁stock s ▁of ▁. 3 0 ▁M 1 ▁ball ▁am mun ition . ▁On ▁ 2 5 ▁February ▁ 1 9 3 2 , ▁Ad j ut ant ▁General ▁John ▁B . ▁Sh uman , ▁speaking ▁for ▁the ▁Secretary ▁of ▁War , ▁ordered ▁work ▁on ▁the ▁rif les ▁and ▁am mun ition ▁in ▁. 2 7 6 ▁cal iber ▁ce ase ▁immediately ▁and ▁completely , ▁and ▁all ▁resources ▁be ▁directed ▁toward ▁identification ▁and ▁correction ▁of ▁def ic ien cies ▁in ▁the ▁Gar and ▁. 3 0 ▁cal iber . ▁ ▁On ▁ 3 ▁August ▁ 1 9 3 3 , ▁the ▁T 1 E 2 ▁became ▁the ▁" sem i - autom atic ▁rif le , ▁cal iber ▁ 3 0 , ▁M 1 ". ▁In ▁May ▁ 1 9 3 4 , ▁ 7 5 ▁M 1 s ▁went ▁to ▁field ▁tri als ; ▁ 5 0 ▁went ▁to ▁inf antry , ▁ 2 5 ▁to ▁caval ry ▁units . ▁N umer ous ▁problems ▁were ▁reported , ▁forcing ▁the ▁rif le ▁to ▁be ▁modified , ▁yet ▁again , ▁before ▁it ▁could ▁be ▁recommended ▁for ▁service ▁and ▁cleared ▁for ▁proc ure ment ▁on ▁ 7 ▁November ▁ 1 9 3 5 , ▁then ▁standard ized ▁ 9 ▁January ▁ 1 9 3 6 . ▁The