I have several .30-06's, with certain loads, I get considerable muzzle flash out of 24" bbl models, even in some loads with a 26" bbl. As mentioned above, the .30-06 is a fairly well designed cartridge, even possibly underbored (less powder than it's bore can handle efficiently), so dropping a few inches of bbl length isn't devastating to muzzle velocity and energy. The difference between my 24 and 26" bbls is typically less than 200fps, even less difference with faster burning powders.

And there's the easy answer...if you're concerned about having a short bbl, load your cartridges with a faster burning powder...easy as that.