Lee Loader

I deprimed, tumbled and began loading some 9mm brass. Some was first time reload (my own brass) and some was range brass.
Here's my problem. I started by loading 115gr Berry's plated and found that the bullets slipped through the case mouth of the Winchester brass. This also happened to most of the Speer and Federal cases.
Then I tried loading some cast I have and the same thing. The cast are .356 and 130gr. I use the Lee carbide sizing die and the die is clean. What gives? There is just enough tension to hold the bullet, but after I use the powder through expanding die the bullets slip down into the case!
Is there some way I can size the case mouth tighter to allow me to use these cases? I've got about 200 primed and I hate to just toss them.

I have a 4 hole turret press and at first I had to adjust the powder thru expanding die. You might try tightening it another 1/4 to 1/2 turn and see if it closes. I have mine adjusted to a very very slight bell.
Also mic the bullets to check the diameter. The Lee loader handbook has all the specs. The leading page of 9mm section should give you a measurement breakdown. The next suggestion for your primed cases is to put them thru the primer die again with out pushing out the primer, this will resize a goo portion of the case so you don't have to toss them

First time to use these dies?

9mm is so short you have to make sure they get all the way up into the size die. I might RAISE your powder through expanding die but in the end, careful measurements before/after both size and PRED dies are the key. Measure the bullets too. I've never had trouble with Berry's.

Looks like you've ruled out brass as the issue so it's a die or set up problem I'd guess.

I'd bet on the expander bushing in the through powder die ,it sounds like you have at least a .357 expander in there which would make cast shooters with 359-360 bullet needs very happy . The bushing can be reduced with a drill press and a stone ,file or Emory cloth in a few minutes reduce the step to the desired bullet dia as a first trial it may be enough for what you need . Stop short and polish with steel wool everything that touches the case to final size . Be gentle. 001 disappears in a flash if a part isn't hardened if it is hardened it takes more work until you break through the case hardening then it goes fast . Slow and easy.

If the expander is tapered as an all caliber die adjust up for less flair . This sounds like an cone flat cone caliber specific die insert . Polish and reduce the diameter of the flat step .

All the above and do a lot of measuring and test fitting by hand.

Run a case through the sizing die. Measure/check the mouth ID. It may be difficult but try inserting a bullet into the case, you'r checking to make sure the case mouth is smaller than the bullet. Flare a bit and recheck. If you are sizing correctly the case will measure about .353"-.354" or so, you need a couple thousandths neck tension. This will help you locate where the problem is and then you can fix it...

Thanks to everyone for your input. I finally was able to run the Winchester and other brass. After measuring the case mouths and the sizing die, I removed the primer punch pin from the sizing die, backed the die out slowly until I got the case mouths to where a bullet was snug, and finished the reloading. Both the Berry's and my cast bullets used the same setting. I'm happy again.