I have a 22" barrel on my .270 Win. What bullet weight would give the best efficientcy. Ihave always read that the heavier bullets lose less velocity per inch that the lighter ones.

i would try a 130, 140 and a 150 in the bullet of your choice. which ever one shoots the best use it.
all my 270's have worn 22" barrels and they all liked everything, each one liked one in particular the most.
woofer

I've got a 20" 270, and it shoots 130's very well, a little loud but still is accurate and performs well on deer.