Bad brass

[gotglock99]

Loading some 380 auto and some of the brass will not hold a crimp! Im still able to pushback the bullet with my finger! The brass which does not hold the crimp is the same brass. It's is Winchester brass, is the brass old or worn out? All the other mixed brass I have will hold a crimp, jut the Winchester brass.

[OldShooter32]

Did you measure the diameter and wall thickness? That's probably different and not giving you the crimp. Only thing I can think of that would do it.

[john16443]

Are you sure it was resized in a 380 specific die?

Are you sure you are not over belling the cases prior to bullet seating?

Are you sure you are not over-crimping the round instead of just removing the bell?

Just throwing out some things that may cause weak neck tension.

Give us some information on your equipment and set-up, that may help to determine the cause.

Generally the Win brass is good stuff and you don't normally hear of issues with it.

[gotglock99]

Well I'm using 380 lee dies, in a Hornady LNL AP, using xtreme 100grn FP bullets, with 2.8 grns of titegroup! The only thing I can think of is it's the brass. Only because the win brass is the only one that can be pushed back.

[pisarski]

check the size of the brass with the other to see what is not the same you may need to adjust the dies for that brass

[Munk]

are you using the correct diameter of 9mm bullet?

If the win brass is thinner than your other brass, it won't hold as well, and if your other brass is thick, it'll have more leeway with bullet diameter.

This all assumes your crimp is set correct to begin with.