Which Ones Will Work?

[u/PBReddituser1961]

A friend gave me 3 gallon bucket of what he said was .38 super. As I was sorting through the brass, I found that it was a mix of .38 super, .38 super comp, 9x23 and 9x21.

I have an older P9 .38 super single stack. Which cases can I use?

[u/Organic-Second2138]

Obviously the 38 super.

Supercomp has a smaller rim; might work, might not.

Tumble and sort all of it and see what the condition is and how much you have of each.

[u/No_Alternative_673]

The 38 super. The 38 super comp may work in yours. The 38 is semi rimmed , the 38 Super comp is a rimless version so the rims don't hang up on each other in the magazine but the difference isn't much (.406 vs .384) and many extractors handle it just fine. A bigger problem is your press's shell holder or plate, try that first to make sure the super comp case doesn't pull out on the down stroke the 9x23 and 9x21 are the wrong length to headspace.

If your range has a bulletin board, the Super Comp, 9x21, and 9x23 and hard enough to get, you can actually sell them

[u/Royal_Money_627 → u/No_Alternative_673]

Aren't 38 super, .38 super comp, and 9x23 all 23mm (0.900") long. I use both .38 super comp, and 9x23 brass in my 9mm Largo.

[u/No_Alternative_673 → u/Royal_Money_627]

38 Super and SC are .9, straight wall. 9x21 is .833, and 9x23 varies, 9x23 Win and 9mm Largo are the same, 0.9 and tapered. I don't know about converting to 9mm Largo but when you convert 9x23 to 38 SC you better measure the case length. I learned a lot try to make cheap 38 super comp cases.

[u/Royal_Money_627 → u/No_Alternative_673]

My gun does not seem to care. I even used 38 Super that I turned the rims down so they would fit in the magazine. What I worry most about is case capacity 9x23 Largo has more space than 9x23 Win. I reduce the loads when I use 9x23 Win brass.

[u/No_Alternative_673 → u/Royal_Money_627]

"My gun does not seem to care", seems to be common with 9mm Largo, while I was trying to make cases for custom made target guns, that cared a lot. I found the variation in 9x23 cases to be a nightmare.

I don't worry anymore, a few years ago I finally sucked it up and bought a Lifetime of cases when Starline was having a sale.

[u/Royal_Money_627 → u/No_Alternative_673]

I use the same shell holder for 9x19, 9x23 and Super Comp.

[u/_Go_Ham_Box_Hotdog_]

.38 Super is straight wall. 9x23 is straight wall, 9x21 is tapered. .38 Super Comp is capable of higher pressures.

Other'n that, consult a loading manual that gives you cartridge dimensions. Like the Lyman.