9MM expanding die issues

[pearcetopher]

Hi guys, I was having an issue with chambering so I seperated some CB's from their brass and noticed that the part of the bullet (base) that sit below the case is smaller than the part of the bullet that sits outside the case. The only thing I can think that would cause this is the 9mm case not being flared enough prior to bullet seating. My 4 die case expander is on max and cannot expand anymore. There is a difference of about .001 from nose to base. Do I need to use one of those universal expanding dies to open it up a tad more or is this normal?

Your Canuck,

Chris

[DeanWinchester]

Are you using a Lee factory crimp die?

[Recluse]

You only need to expand the case mouth just enough so that you can seat the boolit without having lead shave. The 9mm is also a tapered case, so you might be swaging the base of the boolit ever so slightly.

What diameter are you sizing your boolits and what diameter did your barrel slug at?

:coffee:

[pearcetopher]

shooting them as cast, they are .3575 bore slugged at .356
not the factory crimp die, the seater and crimp die

[MtGun44]

It is possible to have the case size down the boolit as it is seated. If you are
causing problems in the bore (leading or inaccuracy) due to this unintended
resizing, there are two obvious solutions. One - cast with a harder alloy, or
two - use a larger expander plug. Multiple users have posted that they have
obtained a .38 Spl or other .38 cal expander plug for their die set and have
conquered this problem.

OTOH, if it is just something that you noticed, and there is no actual functional
problem, perhaps it is time to turn on the "ignore" light. ;-)

Bill

[rintinglen]

I had problems of this sort with some brands of brass. I was getting intermittent leading. Pulling a few boolits and miking it revealed that My 358-242s were getting tapered, because the thicker military brass was squishing the relatively soft lead. What I did was take the suggestion of one of our fellows here on the site and buy a Lee 38 S&W, not Special sizer die from Titan Reloading. IIRC, it cost me about 12.00 and solved the problem. The larger expander plug made enough room for my .358 boolits to stay that way, while still chambering in my 9 MM's.

However, Bill's admonishment not fix what ain't broke is a good one. If you aren't having problems you can't live with, then "Ignore" is a good choice.

[MBuechle]

I had this problem with my 9mm loads and it was causing leading in a PT92. I load on a Dillon 550B and the expander is the powder funnel. Ended up turning a custom powder funnel on the lathe at work from drill rod to .356". It does the trick. Leaves the cases seriously coke bottled, but works. Did the same for my .40.

[Moonie]

The 38/357 expander will not work in the 9mm die as the expander is too short. The expander you want is the 38 S&W expander. I had issues with the 9mm expander not expanding deeply enough for the Lee 125gr .358 boolit but with the 38 S&W expander it works very well and chambers perfectly in my friends 9mm.

[jmort]

I like the Lee Universal Expander.