>>10609376For whatever reason Takara decided that Optimus should have some 4mm ports, the peg on his sword and the rectangular peg on his puny arm cannon are 4mm. Optimus also has 2 4mm ports on his back, another 2 on his arms and 2 more on his inner thighs in addition to the 5mm ports that are present. I guess it's part of space related reasons so there was only enough room for 4mm ports on the arms, Optimus is limited to what can be attached to him. He can most certainly hold 5mm peg weapons but he can't attach them onto his arms.
On the other hand though, most Diaclone connections are 4mm so this creates an unintentional compatibility with Diaclone weapons. I don't have a lot of Diaclones on me so what I was able to provide for Optimus are from the Big Powered GV Consolidated Battle Trailer as seen in pic-related. I think it works out well.
