Reducing case neck diameter
- Thread starter sydn
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The Bushmaster
Member
aah...And just what are you up to here? sydn...A little more information might help these fine people out just a little....Never heard of bottle necking a .38 Special...
Jim Watson
Member
Hanged if I know, but RCBS, Huntington, or CH/4D could probably tell you.
Their listings of wildcat calibres is not descriptive, it might already have been done under some name. Neckdown of .256 Win (.25x.357) would get you close probably in one step, but I don't know how available that is.
Their listings of wildcat calibres is not descriptive, it might already have been done under some name. Neckdown of .256 Win (.25x.357) would get you close probably in one step, but I don't know how available that is.
I'll build the resizing dies myself. Since the .38 Special is a straight case, a standard .375 reamer can be used for the main body. A standard 60 degree x .375 countersink will form the shoulder, and however many reamers to step the neck down to 6 MM. Probably only thread the last die for the case neck expander.
Randy in Arizona
Member
Unless you already have the barrel, you might take a good long look at the .256 Win Mag.
It is only 13 thousandths bigger and cases are available, as are dies, bullets should be easier to cast, etc, etc.
More bullet mass = more killing power at the same velocity.
It is only 13 thousandths bigger and cases are available, as are dies, bullets should be easier to cast, etc, etc.
More bullet mass = more killing power at the same velocity.
I looked at the 256 and the 25-20 WCF. They both have readily available chamber reamers and headspace gages- a real advantage. However, I'm concerned that the case capacity of these two cartridges is about twice what is needed . I'm estimating that 6 to 8 grains will send a 100 gr 6mm bullet at 1100 fps. I want 90% case fill when I'm done.
There is also the having something different factor.
There is also the having something different factor.
Jim Watson
Member
Well, this is not something I have done very often, .30-30 to .357 Herrett and .45-70 to .33 WCF are about it in my case forming career.
But since you are making your own dies, you can work up to the required set without too much trouble.
Make the sizing die first. Will it neck a .38 to 6mm in one step? If so, good.
If not, make up another and ream its neck area out until it WILL size a .38 down some amount, the exact neck diameter not important.
Will THAT somewhat bottleneck case size down to 6mm in the sizing die?
If not, make up another and ream its neck section out until it WILL size a case from the first die down by some more.
Will THAT more bottleneck case size down to 6mm?
If not, add another step and repeat until you have enough to bring it down.
But since you are making your own dies, you can work up to the required set without too much trouble.
Make the sizing die first. Will it neck a .38 to 6mm in one step? If so, good.
If not, make up another and ream its neck area out until it WILL size a .38 down some amount, the exact neck diameter not important.
Will THAT somewhat bottleneck case size down to 6mm in the sizing die?
If not, make up another and ream its neck section out until it WILL size a case from the first die down by some more.
Will THAT more bottleneck case size down to 6mm?
If not, add another step and repeat until you have enough to bring it down.
Randy in Arizona
Member
Or you could use one of the new very bulky powders such as Trail Boss.
only1asterisk
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More than one step for sure, maybe more than two (although I've heard of people making 256 Win in one pass). I'm thinking you are going to need forming dies in addition to your sizing die to do it right. I'd try a 30 Tokarev die first, anneal the case neck and see if I could go from there.
David
David
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