380 seating issues with coated Missouri bullet

[Haney1]

I have been loading for close to 40yrs. I am stumped as to what I am doing wrong. This is my first time using this bullet. I have used their cast bullets1000’s of them with no issue. The round nose seating stem for my RCBS 380 die gouges the round nose of bullet. I switched to a 357 round nose stem and it is much better.
Any help would be appreciated.ps I have loaded 2k of 380 just before this bullet type no issues. Single stage Rock Chucker.

 

[Seymour380]

I have had the same problem with a few specific brands of cast and coated bullets in 380 acp using RCBS dies and a Rockchucker press. I decided that it was due to softer lead in specific brands of bullets, not problems with my dies.

I don't think you did anything wrong. I will try your solution down the road when I have the same issue.

I am guessing that you clean your dies consistently, so you may have a batch of bullets that had a softer lead alloy used by the same manufacturer. My best thought at this point

 

[Haney1]

I have had the same problem with a few specific brands of cast and coated bullets in 380 acp using RCBS dies and a Rockchucker press. I decided that it was due to softer lead in specific brands of bullets, not problems with my dies.

I don't think you did anything wrong. I will try your solution down the road when I have the same issue.

I am guessing that you clean your dies consistently, so you may have a batch of bullets that had a softer lead alloy used by the same manufacturer. My best thought at this point

Thanks for the reply. Yes I have cleaned my dies. Forgot to mention they mic’d at.356

 

[FROGO207]

You could get another seater stem, either cut to fit or take another of the same type and using wax to cover the bullet and inside of the die body make a plug of JB weld or epoxy putty and force the bullet into it and let it set up. Then take things apart , sand the outside of the pin where it is epoxy so it moves freely and you have a custom seating stem. No more cut coating or dented bullets. Some seat and taper crimp in seperate steps and claim that works but I have not tried this yet so don't know for sure. If you are not scraping the side of the bullet you are flaring enough so pushing that last bit with an improperly fit seating pin is the problem.

 

[EricBu]

You've done absolutely nothing wrong. This problem has come up in the past, and there is literally hundreds of posts on dozens of forums about it. It's just what happens with certain die profiles and cast/coated RNFP and other types. It actually won't affect the performance, but those of us with OCD are irritated beyond belief by that mark. I myself can not live with it.

I have a little mod I do for loading RN and RNFP cast/coated bullets. I take the RN feeding stem, fill it with epoxy, coat the outside of the stem and the bullet with lithium grease, and press the bullet into the seating stem with my vice and let it sit 24 hours. Remove bullet, clean it up, and polish the stem. I've got thousands of rounds on these mods with no issues, and no marks on the bullets. I have a set of these for everything I load, and use them exclusively for the RN cast/coated.

Also, RCBS will send you another seating stem, and even custom make you one if you send them a handful of bullets.

 

[Haney1]

You could get another seater stem, either cut to fit or take another of the same type and using wax to cover the bullet and inside of the die body make a plug of JB weld or epoxy putty and force the bullet into it and let it set up. Then take things apart , sand the outside of the pin where it is epoxy so it moves freely and you have a custom seating stem. No more cut coating or dented bullets. Some seat and taper crimp in seperate steps and claim that works but I have not tried this yet so don't know for sure. If you are not scraping the side of the bullet you are flaring enough so pushing that last bit with an improperly fit seating pin is the problem.

Thx. That way too much work for that. I will continue to use .357 seat stem till I finish loading the coated. Then go back to cast Missouri Bullets.

 

[__steve__]

You could get another seater stem, either cut to fit or take another of the same type and using wax to cover the bullet and inside of the die body make a plug of JB weld or epoxy putty and force the bullet into it and let it set up. Then take things apart , sand the outside of the pin where it is epoxy so it moves freely and you have a custom seating stem.

This is a darned good idea sir

thanks

 

[lordpaxman]

Welcome to THR!
Lots of good advice above. Do you seat and crimp in the same step? If so, you may want to try it in separate steps, that may alleviate the problem as well.
In addition to JB weld in the seating stem to customize it, you can also try a bit of crumpled tin foil that will compress to fill spaces so the bullet nose is covered. There’s also hot melt glue that can customize it as well. Seating stems are cheap, so have at it. Good luck.

 

[Col. Harrumph]

Rather than fuss with epoxy and cleanup, one trick I've used successfully is to loosely pack a small wad of aluminum foil into the seating cup. Not a permanent solution, but it's worked for me.

 

[Jesse Heywood]

Rather than fuss with epoxy and cleanup, one trick I've used successfully is to loosely pack a small wad of aluminum foil into the seating cup. Not a permanent solution, but it's worked for me.

Another temporary solution is hot glue. Apply a drop of candle wax to the bullet tip

 

[ArchAngelCD]

If you are going to continue using that bullet you can contact RCBS and send them a few bullets and they will customize a seating stem for you. I don't think they charge much for this service. You will then have 2 stems that will serve you well.

 

[forrest r]

The root of the issue has nothing to do with the seating stem profile.

You should be wondering how much force it takes to put those marks in the bullets nose when seating them.

As a long time bullet caster mainly using 8/9bhn alloy (range scrap/hill pickins) I learned a long time ago the value of the correct expander die stem.

Most mfg's make dies that are designed to be used with jacketed bullets. The jackets are a lot tougher and smaller in diameter then their cast/lead coated counterparts. If you're using enough force to deform the bullet's noses then you stand a pretty good chance that you're deforming the bullet bases also (swaging them down or out of round). Lyman came up with m-dies for this very reason & rcbs started putting their own m-die expander die out. M-dies expand the case deeper and have a step on the top of them that makes a small shelf that the bullet sits in aids in starting the bullet strait when seating them.


45acp expanders, on top is a factory lee expander. You can clearly see a ring (in the middle of the expander button) that is a high water mark left by the case mouths. The bottom is a lyman m-die that is used like the picture above having +/- 100% expanding depth in the cases.



A home made/custom made expander for the 9mm's next to a factory expander. That home made expander is used for cast/coated 9mm bullets sized to .357/.358" in 9mm cases.


Basically your using the bullets you bought as a bulldozer to open the 380acp cases wide enough/deep enough to accept those coated lead bullets simply because you're using a a small/short expander to flare your cases that is designed for jacketed bullets.