The generator matrix

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

generates a code of length 48 over Z7[X]/(X^2) who´s minimum homogenous weight is 252.

Homogenous weight enumerator: w(x)=1x^0+312x^252+1032x^259+1560x^266+1740x^273+2058x^276+2046x^280+24696x^283+2262x^287+74088x^290+2364x^294+2346x^301+1800x^308+942x^315+306x^322+90x^329+6x^336

The gray image is a linear code over GF(7) with n=336, k=6 and d=252.
This code was found by Heurico 1.16 in 10 seconds.