AR15.Com Archives
 How to neck up a cartridge.
the_ak_kid  [Team Member]
5/30/2008 3:16:34 PM
So I'm sitting around my shop, fiddlin' with my reloading bench, and I get to thinking about a wildcat cartridge my brother and I have been discussing for awhile.

I start to think that maybe if you necked up a .308 case to 338, and then shot 220 grain bullets, it might be cool.

I know it would be kinda slow, but it would be a heavy bullet out of a short action, and all you'd have to do is re barrel your rifle to 338 and voila!

Has something like this been done commercially??

I checked a couple book, and didn't find anything.

If I were to try this, what powder would I use? fast or slow?

How would I be able to know what chamber pressures were, without actually shooting?

How would I neck up a cartridge??

Thanks in advance. Scott




ETA: Shit.

Back to the drawing board. Either that, or I'm gonna have to buy a 338 Federal.
strat81  [Team Member]
5/30/2008 3:30:15 PM
Federal already beat you to it.
.338 Federal
Skg_Mre_Lght  [Team Member]
5/30/2008 3:42:49 PM
I hate to break it to you, but within a couple of months of the release date, almost all new cartridges have been "Wildcatted Out" meaning that you will add nothing new to the arsenal that hasn't been done.
AeroE  [Moderator]
5/30/2008 6:28:05 PM
Don't give up, the hard work is already finished and I suspect you can have a chamber reamer on your doorstep is just a few weeks.

You could even go really old school and get the barrel you already own bored and re-rifled, but there are probably only two or three men left that do that work now, everyone pretty well sticks a new barrel on.

I probably have load data at home.

You could also get a custom reamer made Ackley style (and I expect the makers already have a drawing for that one, too) and call it the .338 08 Improved Texan. 08 for 2008 and .308 Win, the parent case. Easy to make cases for this one, too.


See the IM I sent. One other idea - are you familiar with the .35 Whelen? It's perfect for your hunting and still pretty popular in Texas. Maybe the only down side is the case is a necked up .30-06, so it's probably too long for your rifle to feed from the magazine.


M1A4ME  [Member]
5/31/2008 7:40:42 AM
Every 25.06, 270 Win and 280 Rem. empty I pick up becomes a 30.06 case.

I do this by tapping a punch down into the case mouth to start to "bell" the case mouth. Once it is large enough for the expander to start into I just put some lube on the inside of the case mouth and on the outside of the case and run it through the resizeing die.

Now I have 30.06 cases and once they come out of the polisher again they are ready to prime and load.

I do the same thing with .243 Win. and 7mm08 to make them .308 cases.

Every now and then I split a case neck during the resizing, but not often.
Njanear  [Member]
5/31/2008 8:57:08 AM

Originally Posted By AeroE:
One other idea - are you familiar with the .35 Whelen? It's perfect for your hunting and still pretty popular in Texas. Maybe the only down side is the case is a necked up .30-06, so it's probably too long for your rifle to feed from the magazine.


Along the same lines, he could always just make the same jump in bore size and get a .358 Winchester that will fit his existing action.

Now if he really wants to make a wildcat that no one else has done, he could make the jump to an odd bore size, like the .348 or .379 (.38/55) or ??? Of course, then he would have to start getting custom-made spitzer bullets for it in order to see improved ballistics.