why size the 9 mm ?

[edwin41]

hi , im doing a little reading for the 9 mm luger cartridge .
it seems to me that there are some issues with the bullet sizes , but .357 would be the most common in cast.
the steps would be to clean the fired brass , then make them smaller in a sizing die , then open them up again
with a suitable neck expander , like a m die from lyman, and them give them a light crimp again.

so , i picked up some fired brass from the range for some measures...
i took a .38 special wadcutter that i cast myself , and sized it .357.
the fired 9 mm brass took the bullet with firm thumb pressure , so the bullet would not be sized down or so.

now my thinking would be that one could clean a casing and push out the primer with a lyman universal deprimer.
give the mouth a little flare and set youre casted bullet at the right OAL , then taper crimp them with a lee
factorie crimpdie , in . 38 special of course.

when you look at the 9 mm casing , and measure how far the bullet sits in this casing and mark this with a pen
and look how high the webbing is , mark this also with a pen , then you see that the to size part is actually
very small. the portion where the bullet sits is always the size it is now , full resizing or not.
the portion between the two penstripes would actually fit your chamber much better this way , and if this size
is no problem to eject from the chamber , it would also chamber just fine with a little help from the mass
of the bold and mainspring.

i have no experience in reloading the 9 mm cartridge , but i will be in the near future , as i bought me a
cz 85 combat pistol , and my castings would be dead soft , like 9 BHN or so.

[edwin41]

another ting ive been thinking on , that is the crimping part.
when we trim the lenght of a cartridge to a certain lenght , and we keep this lenght for all our brass, then we could make a ring of aluminium or so , with a hole drilled through it , and at a certain lenght.

this ring we could slip over the to be crimped cartridge , some when we go up with the ram the ring would stop the upward movement , it will be between the shellholder and the frame.

this will eleminate the need for fine adjustments of the die , and all youre further crimping would be exactly the same over and over again.

[Larry Gibson]

You resize the case for reliability of chambering. 9mm cases expand at other than the case mouth; at the web. It does not take much resistance in feeding and/or chambering a cartridge in a semi auto handgun to prevent the slide from going all the way into battery. If not in battery the handgun should not fire. If it does fire out of battery you have other problems......much more immediate.

A taper crimp is used simply to straighten out the case mouth flair. I've never trimmed a 9mm case in my life and never intend to. I've fired thousands of my own cast bullet 9mm loads over the last 45 years in numerous handguns and subguns. My current CZ75 shoots my reloads very well.

You are over thinking the situation. Your 9mm handgun is a "combat" pistol.....not a match pistol. Such loading techniques you're discussing will make no difference. Follow the directions for your dies. Size the bullets .357, lube them, load them as per the die instructions and go shoot them.

Larry Gibson

[edwin41]

thanks for the response larry , and you might be right on with me overthinking.
would be nice though , to have a common 9 mm that can shoot side by side with my smith .38 target masterpiece.

the cz pistol is not yet here though , it will take some time to get here.
im gathering some information for now , and making a list of what to buy , i much favor lyman
moulds and dies , but they are not really fast delivered here in holland.

i think the lyman 356402 120 gr would be a good choice ?

[RobS]

http://castboolits.gunloads.com/showthread.php?121607-Setting-up-for-boolits-in-a-new-9mm

You will want to size your brass for the simple reasons that Larry brought up. The 9mm is not a cartridge that has much wiggle room when it comes to a shorter COAL. The brass case tension is one very important part of the reloading process that keeps a boolit/bullet from setback while cycling in the firearm. A KaBOOM could be your ending result unless reloads are performed correctly.

[Larry Gibson]

The 356402 is an excellent choice! It's the very bullet I started out with in '69 with a single cavity mould. I sure cast a gob of bullets in single cavity moulds back then. Thought I had it made! I gravitated to other 9mm designs in 2 and four cavity moulds. Got a Lee 356-120-TC 6 cavity mould and haven't used another for some years now. Had a good 356402 in a Lyman 4 cavity and let myself get talked out of it........a real regret........

Larry Gibson

[FergusonTO35]

I really like the Lee 356-120-TC. Shoots great in all my pistols.

[Love Life]

^^ Are you interested in selling your factory barrels?

[Bonz]

It's important to remember that the 9mm Luger case is actually slightly tapered; the case opening is smaller than the web of the case. I use my Case-Pro roll sizer to do the initial resizing of 9mm Luger brass which actually reduces the web down to .388" This gives me improved case opening tension.

[MtGun44]

If you don't have proper neck tension and the boolit pushes back in the case -
the pressure will skyrocket. VERY dangerous to have weak neck tension and
inadequate taper crimp. Both are needed, so if you can seat a boolit with thumb
pressure, you are in dangerous territory, pressure-wise.

I agree 100% that the Lee 356 130 TC conventional design is a great design that
works well in all my different 9mms. I size it to .357 or .358 depending on
which guns it will go to, although .358 is steadily becoming my standard, seems
to work well in all.

Bill

[GREENCOUNTYPETE]

I run the lee 356-120tc standard lube groove as they drop about .359-.360 with 4.5 gr power pistol with just enough taper crimp that they load in both 9mm i have, yes it swages them down a touch on loading but they stay big enough to fill the bore at .357 , and work very very well , in my little LC9 it shoots better than most anyone would think a pocket pistol should

cast, tumble lube and load. why add un-neccasary steps
I run a carbide size/deprime die, primer seats on the down stroke , then powder/flare, then bullet seat, then taper crimp because it makes chambering 100% 4 pulls and on to the next round the bullet doesn't go any where and still comes out .357-.358

i do know they don't chamber in everyones gun , but they chamber very will in mine

[edwin41]

thanks for the replys , wasn t one of my best ideas i think.
i tried to load a .38 special case unsized , and that didn t work at all , so a high pressure round like the 9 mm would defintly
be a no go.

[Motor]

The "taper crimp" used with 9mm and other cartridges like it has very little to do with keeping the bullet from moving inside the case. As L.G. wrote, its used to remove the mouth flair. If you read the reloading manual most clearly state to "crimp" just enough to make the case straight again. Sure its fine to go a little more but there is no reason to go beyond a .002" reduction in diameter at the case mouth.


Nearly 100% of your "bullet hold" is provided by neck tension. This BTW: is true for nearly every common cartridge we load.