The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1  1  0  1  1  1  1  1  X  1  1  1  1  1  X  1  1  1  1  1  1  1 2X  1  1  1  1  1  1  1  1  1  1 5X  1  1
 0  1  1  3 5X+2  0  X  X 4X  6 5X+4  5  6  3  1 5X+1 5X+2 5X+4  5 X+3  1 X+6 5X+1 4X+2 4X+4 X+5  1 6X+1 X+6 4X+2 X+3 6X+4 4X+5 3X+6  1 3X+1 3X+3 X+2 2X+4 4X+5 4X+4 X+5 3X+1 5X+3 3X+6  1 3X 2X+2
 0  0 5X 3X 6X  X 2X 4X 3X  0 5X 4X 6X 2X 5X 4X  X 2X 3X 6X  X  X 6X  0  X 5X 4X 3X 5X 3X 5X  0 2X 4X 6X 2X  X 5X 4X  0 6X 6X  X  0 2X 3X 2X 6X

generates a code of length 48 over Z7[X]/(X^2) who´s minimum homogenous weight is 280.

Homogenous weight enumerator: w(x)=1x^0+5058x^280+4296x^287+7428x^294+18x^301+6x^329

The gray image is a linear code over GF(7) with n=336, k=5 and d=280.
This code was found by Heurico 1.16 in 15 seconds.