338/284 ??


Dec 20, 2006
Looking for a second barrel on a short action and considered a 338 Federal ... then I came across the 338/284... it seems to fall above the Fed and near the 338/06 (?)
Having seen some figures that looked at the top end of efficient I wondered if anyone has any real hands on feedback on the 338/284 ??
Many thanks for any replies.
While I cannot give you an answer from personal experience I can suggest a few things.

A while back I considered rechambering a 358 win to 358/284. I necked up the 284 and did a comparison of case volume by filling each with water. The gain would be so small that it wasn't worth the cost of a custom reamer and dies not to mention the gunsmithing costs.

You can do the same with the 338 federal vs the 338/284. Once you get the numbers for how much water each case holds find out the percentage increase for the 338/284. Then divide that number by 4 and you will get the approximate increase in velocity.

I would suggest an easier way. Make a 338 RCM. It IS exactly the same volume as the 338-06. Dies, brass are available at very reasonable prices. You will need a reamer which is approx $140 from Pacific tool and gauge. How do I know? I am in the process of making one. Waiting for the new barrel.
AZshooter thanks for the info: using your approach it suggests that some of the data I found could be over-optomistic!
As to the RCM it looks ideal, but I think over here it would fall into rare to mythical category!
Fortunately this project is on slow-cook
Again thanks for your time and experience.
It isn't my approach, it is John Barsness who came up with the volume comparison and the 1/4th velocity bit....
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