How is this possible? Federal ammunition with 180 grain Accubond bullet in both cases.
30-06 2700 fps
338 Federal 2830 fps
338 being a shorter bullet and less friction ??? Please explain. Thanks.

Same way it's possible to get well over 3000fps with the 180gr NP in a 338-06, less bearing surface than the .308" bullets.

http://data.hodgdon.com/cartridge_load.asp

Keep in mind that when you neck a case up, the bigger bore allows you to use "more" powder to drive the same weight bullet...

This is so because as the bullet travels down the bbl, the bbl becomes part of the case capacity... With the bigger .338 bore, you can use more powder and end up with the same psi you would have in the .308 bore...

DM

I think all of the above, PLUS more surface area on base of bullet for gas in bore to act-transfer energy to bullet to accelerate down bbl.

Interesting as when people talk about a high BC bullet of a smaller diameter bullet, reality often is that a larger bore, throwing a lesser BC bullet-BUT faster in same size case, lessens the gap so there is less difference than sometimes appears. Larger bores have higher speeds w/same bullet wt. all else equal, albeit a lower BC bullet, but they offer a larger frontal area for wider potential wound channel, of course then you have to compare SD.....they call analyzing all these variables "mental masturb.....' well you get the idea. Not my phrase, but quoting a former aquaintance, and oh how often true in manuevering through the ballistic maze!