To keep from having to make brass...
 

http://usera.ImageCave.com/Spook/30.338.39.jpg Had reamers ground for two cartridges based on 7.62 X 39 brass....left cartridge is a .308X39 to be able to get Whisper like performance without making brass while being able to utilize the heavier bullets through the correct size bore.
Right cartridge is a 338X39 in an effort to get 338 whisper performance without hunting down 7mmBR brass to reform (stuff gets scarce from time to time). Should also gain on efficiency and use a little less powder.
Both are at magazine (AR platform) length, but I'll do bolt actions first to get a baseline on accuracy potential. Both are one pass through the FL die before seating :smile:
The .308 dies are standard Redding and you can get to the 338 using a 7.62X39 Type S die with the appropriate bushing and expander...seats with a Hornady 338 seater...or Ch4d makes complete sets.

I wish you could of come up with this 2 years ago! What rifle are you looking at? Can you get a bolt head for a Savage that will fit? Maybe if I can get the wife to get an extra job!!!

Great job you did. Some day I will be able to do a 338 build. I am doing the 308x39 sub-sonics now in my AR 762x39. It is only a 1x10 but will stabalize a 308-220gr RN FB for hunting out to 100yds and does the 200gr SP FB even better. How much difference in accuracy and noise between the Bolt Guns and ARs? How much of the bullet of the 338 is down in the case?

You can get a bolt from Sharp Shooters Supply for a Savage action. Have done one myself and Fred got me what I needed.

Hello mr SPOOK, tell us of your progress. What weight of bullets and twist are you going to use?

Fritz, I shot them both today :smile: the 338 was pretty accurate but went transonic....8.7 gr Alliant power pistol w/250 Scenar, so its going to be very efficient.

I didnt have a scope on the AR (I made the 308X39 barrel for an AR) and was just checking for a load that cycled....9.5 gr VVN 110 w/220SMK , magazine length,cycled a 16" w/gas port in pistol position nicely... I think it stayed subsonic too.

Gotta get out the chrono and plan to spend a day at the range, but its looking real good at this point. I think I also need to get Quickload, but I'm not sure how difficult it is to learn.:confused:
I put most of my effort into testing a hotrod 20 cal (20BRX) today....its going to make some coyotes very unhappy.

QuickLoad is amazingly efficient to learn quickly and has paid off in spades with the work it has prevented in load development.

If you have a mock up you'd like performed just send a PM with the details and I can try to get you a datasheet on the 'hypothetical' round.

Thank you for your generous offer...PM inbound:smile:

So have you tried any factory steel case 7.62x39 ammo in your 308x39 chamber?

not yet, should I?