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This is not so much a rumor as more a speculation with the way modeling is going these days. Something I have been thinking about in waited anticipation of some form of 4th ed Ork Codex, do you all think it would be likely that the Nobz in the Ork armies will be required to be placed on the larger round base 20mm as opposed to the current 20mm base. To provide a concept of a much larger ork then normal orks as well as their additional wound.
I only thought of this as I noticed most things in the game that have multiple wounds (tyranids warriors, Krootox) and/or are suppose to be larger in stature their normal troops (battle suits, terminators,etc.) are placed on the 40mm base.
An if they do this change will it effect your ork strategy.
I thought they were on the larger base (at least the mega armoured nobs are).
The Mega Orks are, however the normal Nobz, and your troop nob leaders are not. Which makes me wonder if they are going to be required. I know at one of the the local GW stores here if a SM player walks up with old termie models not on the proper 40mm bases they will get a one time warning to change their bases before they won't be able to use them again till they are switched.
I don't think the management can do that, the rules state that you can not put a larger model on a smaller base however the old spacemarine terminators came on a 20mm base therfore you would not be breaking the rules. If a member of staff said that to me at my store i would tell him to give me the bases for free to do it or it's not going to happen because this is the base that i got with the model.