We are having fun fooling around with a reproduction WW2 Thompson sub machine gun five mag pouch designed for five 20rd Thompson mags. This is the flat wide pouch holding the mags side by side.
After some stretching and verbal language and much patience we have found that five (5) heavy weight 30rd "Korean" M1 Carbine mags fit. Actually fit well inserted empty or loaded either top or bottom first.
All is required is time to stretch the stiff canvas pouch. Soon we will try to see if fully loaded 30 rd Carbine mags fit with rubber caps on one end and on both ends to fully seal the mags.
This pouch fits flatter and closer to the body and holds one more 30rd Carbine mag. Slightly heavier also. Coats and clothing fit better over. Will advise. That is all. :)