No the .308 is not almost identical to the .243. One is a 30 caliber and the other a 24 caliber and that makes quire a difference. I bought my grandson a .243 to start deer hunting with because there is little felt recoil and it will take deer. However, the .308 will do more than the .243 and shoot heavier bullets and has substantially more felt recoil. Both use a .308 cartridge but that is where the similarity ends.