9 x 19 expander plug

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magic mike
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Location: TX

9 x 19 expander plug

Postby magic mike » Wed Apr 18, 2012 3:15 pm

For a while now I have been trying to come up with an accurate load for my 9mm STI. I cast my own bullets from WW lead and I use the Lee 120gr TC design bullet. Lee's six cavity mold is the mold of choice and I have reworked it to throw .358" diameter bullets. My barrel slugs out at .3554 and I size the bullets to .357". I have used Unique, 231 and WSF powders, all with similar results................bad. After much research, I have narrowed the problem down to the expander plug in the powder through expander die. The expander plug is only .170" long and at its smallest diameter it is .353". This .353" diameter extends into the case by .100" or so before the flaring portion of the plug takes over and bells the mouth of the case. So after belling the mouth of the case I am left with a .353" diameter hole into which I am trying to stuff a .357" lead bullet. Pulling a bullet from a loaded round reveals a newly swagged bullet with a base diameter of .353". This, boys and girls, don't cut it! Last time I checked, the bullets are supposed to go through the target nose first, not sideways!

I called Lee today and talked to a tech who told me that the numbers I was giving him in regard to the expander die didn't sound right so they are sending me a replacement expander. He said that the .353" diameter was correct to which I responded that is what the case measures internally when I remove it from the sizing die. The wall thickness of the case is uniform at .011" for approximately .240" before it starts to taper and that is how long the plug should be in order to open up the case so that it doesn't swage the bullet when it is seated. It also needs to be larger than .353" or it's not going to work with cast bullets.

I belled eighty rounds with my Lyman M die for .357/38 to a depth of .240" and loaded them up and went to the range. They performed markedly better so I think I am on the right track.

So in summary, have any of you had similar experiences along these lines? I enjoy the casting experience and also that the lead bullets are easier on the gun but if I can't get the consistency and accuracy I want I guess I will switch to FMJ or JHP bullets. Replies and thoughts welcome.

mike

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daboone
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Postby daboone » Fri Apr 20, 2012 9:20 am

I use the Lee expander die to re-open a case mouth that has been dented and for case alignment on the LM in the #2 priming station. The Lyman M-dies for actual case expansion/belling.

The Lyman Multi-Expand Charge Die System set comes with several M-type expanders. making it a very excellent die for handgun cast bullet reloading.
http://www.lymanproducts.com/lyman/dies/precision-speciality-dies.php For cast bullets the M-die almost mandatory to prevent swaging the bullet. I've had a member of cast bullets turn me some non-standard M-plugs for custom mold or molds that I've lapped to accommodate the mosens, mausers and the enfields I have.

magic mike
Posts: 690
Joined: Tue Dec 06, 2011 10:33 am
Location: TX

Postby magic mike » Fri Apr 20, 2012 10:05 am

Thanks for the reply daboone. I think I will set up my LM with the Lyman die in the first position as I don't decap and size on the press. Since I have gotten my priming system worked out I really don't need a die in the second position anymore other than to use my missing primer warning buzzer mod. I guess I could knock the carbide ring out of the sizing die and use it that way. The third position could remain the same still belling the case mouth. I think if one uses cast bullets that this is the only way it's going to work. Looking at other forums it appears that all the die manufactures only make the 9mm die sets to work with jacketed bullets. The tech at Lee told me they would make me a custom plug for $30 so I might do that as soon as I am confident that the above mentioned scheme works out.

Thanks again for your input. I appreciate it. :wink:

mike

magic mike
Posts: 690
Joined: Tue Dec 06, 2011 10:33 am
Location: TX

Postby magic mike » Wed May 23, 2012 1:10 pm

Just a quick update. I did get a .357" expander plug from Lyman and put it in the M die in station one. I also knocked out the carbide ring in the sizing die in station two and replaced it with a piece of poly tubing so it still centers the case properly just without any force required. Having done all this and still not having what I would call great success in the accuracy department I think that the last demon to slay is getting my lead up a few notches on the BNH scale. The lands and grooves are so shallow on my STI barrel that I think the main problem is that the bullets are just stripping as they go through the bore and therefore are never receiving the proper rate of spin to stabilize them. Rotometals here I come for some Super Hard. The gun shoots great with 115gr FMJ bullets put together on the same setup so I think the lead is the real culprit here. Everyday is a learning experience. :wink:

mike

WyrTwister
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Joined: Sat Jun 11, 2011 10:20 am

Postby WyrTwister » Wed Jul 04, 2012 2:07 pm

magic mike wrote:Just a quick update. I did get a .357" expander plug from Lyman and put it in the M die in station one. I also knocked out the carbide ring in the sizing die in station two and replaced it with a piece of poly tubing so it still centers the case properly just without any force required. Having done all this and still not having what I would call great success in the accuracy department I think that the last demon to slay is getting my lead up a few notches on the BNH scale. The lands and grooves are so shallow on my STI barrel that I think the main problem is that the bullets are just stripping as they go through the bore and therefore are never receiving the proper rate of spin to stabilize them. Rotometals here I come for some Super Hard. The gun shoots great with 115gr FMJ bullets put together on the same setup so I think the lead is the real culprit here. Everyday is a learning experience. :wink:

mike





Standard advice on lead bullets is to use the largest lead bullet in which the loaded ammo will fit / feed / chamber / function /fire in YOUR gun .

And my limited 9 x 19 loading experience is that 9 x 19 has quite a wide variation in boor and chamber dimensions ?

God bless
Wyr


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