Reloads are tumbling

[Blue68f100]

By chance are you using RP brass. I have found the PR brass is normally thinner and softer so you end up with less neck tension. You may need to reduce the size of the expander your using to increase neck tension. I sort out ALL of RP brass for his one reason. If I load it I have to use a smaller expander to get the neck tension.

If you bevel the inside of the mouth you may be able to seat the bullet without using the expander.

 

[FUBAR63]

Well im using some range brass i bought. its mixed headstamps but all of the rounds are doing this so i dont think that its specific to one type of brass. Insofar as the expander this is odd and maybe a tell tell sign to you guys that have more experience with this. Once i size the case, i can go completely around the expander die to seat these particular bullets. In other words the bullet seats without expansion (bullets all measure .355 without fail) The Winchester bullet i pulled and seated needed to have a small expansion done to seat it properly but the rest of these dont. i would say its the bullets themselves if it weren't for the fact that they all look to be made uniformly and all caliper at .355??

 

[Mad Chemist]

Dumb question: you are using a .380 sizing die right?

If the bullets will seat into the case without any expansion at all, either the sizing die is out of spec or the bullets are. What is the inner diameter of the case mouths after sizing?

 

[Potatohead]

What kind of die? I had to send my 380 sizing die back to Lee because it was not creating the desired neck tension. They replaced the die body.

 

[gamestalker]

Try this, I use the following method for all my AL jacketed loads since the inception of the .40 cal., it may work with plated bullets as well, I've been told it does.

Resize a case, chamfer the inside of the mouth enough to create a bevel to allow for the bullet to set up straight, don't bell the mouth at all, and then just seat it, don't apply any crimp at all either. Check and see if the bullets are still not attaining enough neck tension. If they still have poor neck tension, it is either thin brass, under sized bullets ( smaller than .355"), or an out of spec resizing die.

FYI, crimping does not produce any neck tension what so ever. It's the resizing of the brass that provides neck tension. The purpose of a taper crimp / FCD is only to remove any belling of the case mouth and could create a loss of neck tension, if, the brass is over belled, and, or, the mouth is over crimped.

You mentioned factory bullets being .357". If they are jacketed bullets, they should measure .355" for the .380 acp.. So I wouldn't personally put too much stock in a factory bullet that measures .357", as that simply isn't within SAAMI spec for that cartridge with a jacketed bullet.

GS