case expanding question.

[twc1964]

Well fellas, when i use my rcbs die to expand my 9mm cases, i believe the boolits are getting mushed a bit. After measuring a pulled boolit im seeing around .357 when boolits started at .358. I know ive read about getting a stem for 38sw ?? I cant quite understand this. Can anyone point me in the right direction. The threads on this subject just didnt explain it so i can grasp this idea. Any answers would be greatly appreciated.

[Yodogsandman]

You could try adjusting the seating die up slightly to reduce the taper crimp a bit. Then re-adjust your seater stem for your optimal OAL.

[Doc Highwall]

twc1964, you have the right idea about getting a 38/357 expander for your 9mm. Others have done the same thing and it allows you to polish it down to the size that you need for your bullets.

[upnorthwis]

This is a very common problem. On my Dillon 550B, the powder funnel/expander was only .353 dia. and the brass would crush the boolit so small they came out the barrel sideways. I made a larger one .356 dia. that with PC cured the problem.

[HiVelocity]

FWIW, I solved the same problem by ordering a larger expander for my Lee Universal Expanding die from Night Owl Enterprises. His size/caliber specific collet opens the case mouth to "my" specific diameter, thereby resolving my bullet deforming/distortion. Al is making neck expanding collets for different dies; check them out. Made all the difference.

NOEbulletmolds.com

HV

[twc1964]

Ok fellas, i guess i can pull the expander rod out of my rcbs 38-357 die and try that. Its not mashing em as much as some have found but i want the most accuracy out of my loads that i can squeeze out of em. Thx for the responses.

[sdcitizen]

I believe the reason people use the expander from a 38 s&w instead of 38/357 is that the former is nearly the same length as the 9mm expander instead of being too short. Can't say for sure though, i'm very happy with the noe expander.

[zubrato]

I have Lee dies, and I use the 38S&W expanded in my 9mm die. It works like a charm, and I've been very happy loading my .358 9mm boolits without getting swaged down. Another critical component of not swaging down your bullets is to water drop them and age the boolits for 2+ weeks minimum after sizing.

Believe me I tried to use my 38/357 expander and it did not work, it doesn't reach down nearly deep enough, and gave my 9mm cases an insane trumpet flare while still swaging down my boolits.

The part is literally 3$ from lee, but I don't know if it would work in your RCBS die.

I hope you found a solution to your boolit swaging problem!

[John Boy]

The expander plug in the powder charger on a Dillon 550B die set does an excellent job expanding & flaring the mouth

[twc1964]

Thx all for the tips. My boolits are at 13.2 bhn after aging . I was hoping that would be hard enuff. I guess i could call lee and see if they will sell the 38sw expander die separately. Worth a shot.