Based off of the 300RUM.The 300RUM is .10" longer than the .338RUM so you get a little more capacity.And it works out great cuz i've had a 300RUM for years so I've got tons of brass. Shoots pretty good,I know,I missed the quarter.Heres an artical on the 338EDGE. Snipers Paradise
Love the 338 RUM. I bet the 300 necked
up to 338 is a great round.Have built a few 338 RUM for me and someone always wanted them more than me.I am from North West New Mexico and have taken a few people from Arkansas out elk hunting.One got his elk with a 338 Rum of mine and had to buy it before we left to come back to Arkansas.He still brings it over to load some shells every year before hunting season.Hunts whitetail with it,wow.