Help with Lee 356-120 tc boolits

[Krp68]

I'm new to casting. I'm casting the Lee 356-120 tc for 9mm. I am powder coating and sizing to .357. Using a NOE expander and a Lee taper crimp die when loading. My barrel slugs at 3.555.

My problem is that 1/3 of what I reload will not chamber. I use range brass. I think what my problem is where the taper of the case starts or thickness of the different manufacturers of brass. On the brass that won't chamber, I get a very slight buldge where the base of the boolit sits. I know that I can measure and sort brass but I'd like to avoid this if I can as it adds a lot of time. I don't mind if I have too though.

Is it me doing something wrong? Should I try to size at .356 and see how that works?

Thanks for any feedback.

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[KVO]

What gun and what brass? 9mm brass is all over the map for thickness, I've had problems with S&B bulging as you describe. Federal typically has the thinnest side walls, enough so that I was able to load 158gr SWC (just to see if it would work, no real purpose). If you can narrow it down to a brass issue, you could just pitch the offending makes. I'd not size any smaller for a 9mm.

[upnorthwis]

Don't size the bullet before loading. I let the taper crimp die do the sizing. Plunk test is the best. I got fooled once by a gage and it had me taking the size too small. Which will lead to the worst leading you can imagine.

[Krp68]

I have the same problem for my Glock 17 and M&P 2.0.

It seems that the only brass that 100% chambers is blazer. I'll have to pay attention to the federal and see if I am having any problems there. Everything else I have tried is hit or miss. S&B being one.

I wasn't sure if I should try .356 and see if I could eliminate the problem. Thanks for the feedback.

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[MT Gianni]

In one of the many stickies on loading for a 9 it tells you to replace the expander on a lee die with a 38 one. This prevents the bulge and gives you a better entry for the bullet to prevent shaving. If your bulge is so large that it will not chamber it does need to be sorted. I get my best groups in a 9 by using sorted and weighed brass. I keep it in Costco mixed nut tubs and shoot only that brass at the range. When you weight sort and see the variations in 9mm you understand that pressures will be all over the map with different brass.

[KVO]

For what it's worth I size all my 9mm boolits no smaller than .358" with mixed brass and various boolits for EAA, Sig, Springfield, and one or two other pistols. The tightest 9mm chamber and throat I've owned so far was actually my 357/9mm convertible Ruger Blackhawk. Wouldn't chamber half of my ammo until I opened up the throats. I've heard M&Ps have tight chambers. Can't speak to 9mm M&Ps as mine is a .40S&W.

[gwpercle]

The 9 mm is a stinker to get all the details worked out for. After 45 years of loading handgun the 9mm was the only one that had me saying curse words at it.
I use that exact boolit and size to .357. The seating depth is the tricky part. Newer guns don't have much if any throat, older guns , like a WWII Walther P-38 have a lot of throat and the boolits can be seated out. The new guns, with little throat, required I seat the Lee boolit all the way to where the tapered cone started . If hardly any of the .357 part of the boolit projected past the case mouth , it would run into the rifling and not fully chamber and sometimes get stuck...that's when I did a bunch of bad name saying.
If your gun is newer , deep seat the boolit so that very little of the .357 part extends past the case mouth.
Do the seating experiments with a dummy case , no primer , no powder. seat a boolit and see if it will chamber, no ? seat a little deeper and try again. Once you get it right and the dummy chambers and extracts, keep that dummy to set your seating die with next time. Saves a bunch of work .
I also use mixed range brass, it's not the brass it's that miserable 9mm Luger with cast boolits.
Gary

[Larry Gibson]

Try backing the FL sizer out a tudge so the expander just expands the inside .001+. If the rounds with a "bulge" at the base of the bullet are not equally "bulged all the way around the case the bullet is not seated straight......it is canted. Some begrudge the Lee FCD but adjusted correctly it can make such rounds fit so they chamber. I use the FCD with some "range" brass that is all mixed makes. It works. Also with a groove of .3555 I would sized .356.

[Hounddog]

The seating depth is the tricky part. Newer guns don't have much if any throat, older guns , like a WWII Walther P-38 have a lot of throat and the boolits can be seated out. The new guns, with little throat, required I seat the Lee boolit all the way to where the tapered cone started . If hardly any of the .357 part of the boolit projected past the case mouth , it would run into the rifling and not fully chamber and sometimes get stuck...that's when I did a bunch of bad name saying.
If your gun is newer , deep seat the boolit so that very little of the .357 part extends past the case mouth.
Gary

This is the exact same issue I get with this bullet when I let the length get too long. When I crank my seating die down a little more like Gary says above, the rounds run just fine in my CZ, Glock, and my H&K.

Hounddog

[Cherokee]

In my XDM Comp and 1911 Briley match barrels I size to .356 and seat at 1.055" OAL. Haven't had a problem in about 50k rounds. I use a Lyman 38AP expander button which ends up with a slight bulge in the case but expands enough to not re-size my .356 bullets. As I said, no problems. I do use sorted brass. Winchester and Federal primarily. Remington brass is really thick so I save it for jacketed loads and use an RCBS 9mm expander.

[Ed_Shot]

To what over all length are you loading your 9MM with the 356-120-TC? I agree with Mr. Gibson, if your bore is .355 the Lee FDC may be your friend.

You can use your barrel's chamber but for 9MM a chamber gauge is really handy IMHO. Does your (empty) freshly sized and de-primed brass easily fall into your chamber/chamber gauge? If so, and your loaded rounds won't chamber, it's not the brass, it's something you are doing (or not doing).