Python 3, 123 101 98 bytes
for i in range(1,52):r=[chr(j+65)for j in range(abs(26*(i//26)-i%26))];print(''.join(r+r[-2::-1]))
lol I am really bad at this
thanks @Leaky NunLeaky Nun for the r[-1::-1] == r[:-1][::-1]
tip (:
Alternative solution, with help from @Leaky Nun (8885 bytes)
for i in range(1,52):r=[*map(chr,range(65,91-abs(i-26)))];print(''.join(r+r[-2::-1]))