You guys made me do math...
as an example I used Frontier.
7.62x39 $350 for 1500. Which is 23 cents a shot
7.62x54r is $210 for 400 which is 53 cents a shot
http://frontierfirearms.ca/chinese-7-62x39mm-123-grain-fmj-1500-corrosive/
http://frontierfirearms.ca/s-b-packed-7-62x54r-fmj-corrosive-400-rounds-per-case-surplus/
Using budget shooter supply as my example
.310 Berry's 7.62x39 $20 for 100 is 20 cents
.310 Hornady is $34 for 100 which is 34 cents
.311 PRVI is $40 for 100 which is 40 cents
I used accurate 1680 as an example, $40/lb which is 1 cent per 2 grains so lets say you load 25gr so its 28 cents for powder
total is
48 cents for berry's; and
62 cents for hornady.
68 cents for PRVI
http://www.budgetshootersupply.ca/catalog/762x39_310_45.cfm
http://www.budgetshootersupply.ca/catalog/Rifle__Pistol_Reloading_Components_2.cfm
Factor in your own brass and primers.
Assuming that your 303 British will do .310 breaking down 7.62x39 ammo will save you 25 cents a shot compared to loading the conventional way. That's pretty legit savings. Is it worth that extra effort?
Breaking down 7.62x54r will save you about 15 cents. not bad, that is not worth the extra effort to me. Unless of course there is a shortage of .311-.312. My Enfield can shoot .308 accurately so .310 is an option for me.
I hope that math is right. please correct me if its wrong
P.S. $39 for 20 at Cabela's is $1.95 a shot (vomit)
http://www.cabelas.ca/checkproductvariantavailability/933?specs=19413