M&P 9mm problems with Lee 358-125-RF

[Rizzo]

I slugged my M&P 9mm barrel and it came out as .3565" so I bought a Lee .358-125-RF mold and cast some bullets and sent them through a .358" sizer die.
Initially set the COAL at 1.080" and they failed the Plunk Test in the 9mm's barrel.

They would not pass the test unless I set the bullet to 0.998" COAL.
That seems awful short to me so I resized them to.357" and they passed the Plunk Test at 1.020 COAL.
That also seems a bit short and now they are at .357" rather than the desired .358".
I can see on the lead bullet a mark from where it was hitting.
I am now looking for a different bullet mold design that hopefully is not as wide as the 358-125-RF so I am not setting them so deep.

Anyone run into this?
Suggestions?

Thank you.

[Moonie]

That boolit does need to be seated very deeply for 9mm. I have that mold in a 2 cavity and while it will work, the 356-120TC works much better in 9mm, I purchased a 6 cavity after having similar issues with the 358-125 RF as you.

[tazman]

I also vote for the lee 120 tc. It works flawlessly in my pistol.
I have used the 125 rf loaded fairly short but accuracy wasn't all that great.

[gwpercle]

have been working with loads for a WWII Walther P-38. The two Lee bullets that have given good results are #358-105-SWC, this is a 38 special boolit but I'm trying to work up some lighter loads for the old war horse. The P-38 feeds them when seated above the lube groove, just shy of the first band. It seems rather short but it works and I like the accuracy. Light loads that reliably function the action shoot to point-of aim.
The other is Lee #356-125-2R, a standard RN 9mm luger boolit. My friend wanted a round nose profile more like the hardball ammo he shoots and bought it for me. He was afraid the semi-wadcuter would not feed in his gun.
Both bullets sized to .357, cast of 50 / 50 COWW and lead with 1% tin added, air cooled.
He reports it feeds, fires , ejects and has as good accuracy as with white box ammo.
Gary

[wv109323]

I have a CZ that has the exact same bore size as yours. .3565. I had to keep a bullet diameter of .358 ( actual .3577 out of my Star bullet sizing die) to get any accuracy. I had an RCBS mold .356- 124TC that cast at .3569. I could not get that bullet to stabilize at that diameter. I got the Lee 358-125 RF. My CZ will chamber that bullet with the bullet seated in the crimping groove.
I think you will need to stay with a .358 mold with a different nose profile that will chamber in your pistol.

[MtGun44]

This is why I recommend the Lee 356 120 TC over any of the round nosed or RFs
in 9mms. Throat fit issues dominate. Great design for a revolver, not so much for
many 9mms.

Bill

[Rizzo]

Thanks for all of your replies and suggestions.

It seems that the recommended Lee 356 120 TC mold is pretty popular.
However, it is not my desired .358" diameter bullet, since my slugged barrel measured .3565"

I ended up ordering a Lee Precision 6 Cavity 358-105-SWC mold.
Hopefully that nose design will pass the Plunk Test without being seated too deep.

[tazman]

As it happens, many people have problems getting the 105 swc to feed properly in their 9mm pistols. I am one of them. After many weeks of experimenting and frustration, I gave up on it all together. I wish you luck with yours.
My Lee 356-120-tc drops boolits with a diameter of .358 which is a good thing because that is exactly the diameter I need for my 9mm.
If your 120 tc mold drops small, there are several methods of correcting that particular issue talked about on this site. A couple of them are really simple and easy to do. Beagleing come to mind.

[farmerjim]

My Lee 358-125-RF sized .359 and Red Copper Hi-Tek coated works great in all my 38s and .357 mags and 357 Max . Sized .357 it works great in my Kel tek PF9 and my Hi-Point 9mm.
I have not tried it in my M&P9. The Lyman 356402 sized .357 and Hi-Tek swamp green coated works great in all my 9mm s including the M&P 9.
I have to go check out the lee in my M&P and I hope it works because I just loaded 1,000 of them. I don't need that many for the Kel-tek and Hi-Point.

[Shiloh]

What Moonie said in post #2.

The base is longer than both the 125 gr. RN and 120gr. TC. My 120 gr. TC does not drop large enough for 9mm's.
Begin at the given Start Load in your load resource.

Shiloh

[Quiettime]

Measure some brass and try loading with the thinnest walls, maybe that will help. 9mm is a challenge with boolits. I pretty much gave up on it, but it is doable.

[MtGun44]

.3565 groove diam - my bet is you will not be happy with .357. Normally, .001 oversized
is about absolute minimum oversize that works in pistols - and 9mms seem to want more than
usual. Good luck but I'll bet you will be at .358 to get best results.

BUT - only Mr. Target knows the real answer, all else is just an educated guess.

Bill

[Rizzo]

As it happens, many people have problems getting the 105 swc to feed properly in their 9mm pistols. I am one of them. After many weeks of experimenting and frustration, I gave up on it all together. I wish you luck with yours.
My Lee 356-120-tc drops boolits with a diameter of .358 which is a good thing because that is exactly the diameter I need for my 9mm.
If your 120 tc mold drops small, there are several methods of correcting that particular issue talked about on this site. A couple of them are really simple and easy to do. Beagleing come to mind.

I received my Lee 358-105-SWC mold today so I cast some bulets and sure enough I have the same problem as the 358-125-RF.
I cannot pass the Plunk Test unless I seat the bullet to about 1.000" <sigh>

I have ordered a Lee 356-120-TC mold to see how that goes.
This is getting to be a little expensive trying to get a 9mm cast bullet to work, not to mention a bit frustrating like you experienced.

A sized and belled 9mm case fits fine in the barrel but my barrel throat is .3576 or so, so it is the .358" bullet hitting that area that is giving me grief. I can see the mark on the lead when removing the Dummy Round.
Perhaps I can find another bullet profile in another brand mold (I'm using Lee's) that will work but I am quickly losing patience and will probably end up using some .355 FMJ that I have been using prior to this if the 356-120-TC mold doesn't work out.

Thanks again for everyone's input on this.

[tazman]

If you load the 120-tc so that the shoulder of the nose where the cone begins is right at or barely in front of the case mouth it should feed fine.

[Rizzo]

If you load the 120-tc so that the shoulder of the nose where the cone begins is right at or barely in front of the case mouth it should feed fine.

Thanks for the tip tazman.
When I receive the mold and cast some I'll report back.

[pakmc]

I tried all three Lee molds for 9mm in the 124gr. range. none worked in my CZ champion, or my CZ 75D(my carry gun.) I just ordered a mold from accurate molds in the 130 gr weight. it will be about a .358or9 dia. Two of the molds from Lee in the 124 gr, range work just fine in 38/357 revolvers the third mold from lee has a left hand screw on the spruce plate. You can see the difference because the screw will back out as you close the spruce plate. I usually use 6 holers Lee molds but I"ll take a accurate molds one If and when I can aford them. I did order the mold a little large incase it doesn't work in my 9mm pistols, I can always use them in a revolver.

[tazman]

For curiosity's sake, what was happening that the 124 grain Lee boolits didn't work?

[Rizzo]

If you load the 120-tc so that the shoulder of the nose where the cone begins is right at or barely in front of the case mouth it should feed fine.

Well, I received my Lee 356-120-TC mold and cast up some bullets.
Fortunately they dropped larger than .356" (some .360") so I lubed and pushed them through my .358" sizer die then started making some Dummy Rounds to do the Plunk Test.
I ended up like you mentioned in your Quote above with a COAL of 1.035" which is a lot better than the .998" - 1.000" I was getting with the other molds.
I used my M&P 9mm barrel to do the Plunk Test.

So, I made a batch of rounds loaded with 3.4, 3.6, 3.8, 4.0, 4.2, 4.4 grains of HP-38 and shot and chrono'd them today.
Success! No obvious pressure signs and I liked the accuracy of the 4.2 loads the best. This was at 7 yards bench rested. Chrono averaged 1093 fps.

It was a frustrating journey but I'm a happy camper now and wanted to say thanks again to everyone who contributed to this thread and pointed me towards the Lee 356-120-TC mold.

[tazman]

Always good to hear a success story. Keep it up.
That load is well within the suggested range on the Hodgdon load data site. As usual, the most accurate load seems to fall somewhere below the max load.

[Floydster]

The 120 tc bullet is my go to for my 9mm's and my 38 spl. And 357 mag.
Sized to .357 for my 9's and .358 for my revolvers.
I powder coat these bullets also, very accurate.

[Virginia John]

I use the Lee 356-124 TC with 4.2 HP-38 under and seat it just at the shoulder. It passes the "plunk test" and it works great in all my 9s.