Making that perfect 9mm cartridge

[Wheeljack]

I size the case, flare it and add powder, put bullet in seating die to remove flare and seat bullet. I'm working with a coated bullet. Then I look at the finished bullet and find some shiny lead at the mouth of the case. I have made sure the case was flared enough but the bullet still shows signs of the coating being scraped to the lead. I pull the bullet and find a very fine line when the mouth of the shell touches. I use a Lee single stage press and I like it that way. The only thing I can think of is to use a chamfer tool. I don't look forward to this extra step but I can't think of what else there is to do. It just seems the rim of the mouth of the shell has ridge inside it.

Does anyone else have this problem?

[judgecrater]

I would think you are over crimping. You only want to just remove the flair. Additionally I would recommend seating and taper crimping using separate dies. Using one die, the bullet is still being seated (and in motion) as you crimp and can scrape the bullet. No need to chamfer.

[TDA]

Are you using a Lee seating die?

[bandw1dth]

I size the case, flare it and add powder, put bullet in seating die to remove flare and seat bullet. I'm working with a coated bullet. Then I look at the finished bullet and find some shiny lead at the mouth of the case. I have made sure the case was flared enough but the bullet still shows signs of the coating being scraped to the lead. I pull the bullet and find a very fine line when the mouth of the shell touches. I use a Lee single stage press and I like it that way. The only thing I can think of is to use a chamfer tool. I don't look forward to this extra step but I can't think of what else there is to do. It just seems the rim of the mouth of the shell has ridge inside it.

Does anyone else have this problem?

I would think you are over crimping. You only want to just remove the flair. Additionally I would recommend seating and taper crimping using separate dies. Using one die, the bullet is still being seated (and in motion) as you crimp and can scrape the bullet. No need to chamfer.

@judgecrater is right on the money. You need to seat and crimp in two separate steps. I'm gonna hazard a guess and say you using mixed brass, prolly got some range pickups mixed in there, you prolly don't sort by headstamp. And/or don't trim. Keeping the number of times fired uniform across batches is also something to think about. All these are things to take into consideration when chasing that "perfect" 9mm round.

Something specific to coated rounds; your gonna have to play with the amount you expand the case mouth and the amount of "crimping" you apply. Don't think of it as crimping per se. You need to close the case mouth around the bullet without digging to deep into the coating. If you can pull the bullet and the coating is scraped off you've got too much "crimp".

Good luck sir. Don't forget to post progress and or any other questions.

Sent from my iPhone using Tapatalk

[kneelingatlas]

I like a 0.378" crimp

Edited July 25, 2016 by kneelingatlas

[Sarge]

I think the die is the culprit. Coated or even plated should be fully seated before crimping. There is no chamfering or trimming etc needed on these rounds

[rowdyb]

coated bullets have always required just a little extra belling for me to avoid shaving during seating. just this tttiiiinny bit more. and not using an "u-die" or a factory crimp die.

[techj]

another +1 on seating & crimping seperately - it's what I do with coated bullets. It will also let you get by with the minimum flair needed (still more than jacketed) to seat the bullets.

I use a standard expander die and use an FCD for the crimp.

[Wheeljack]

Well after lots of measuring and poking around, I think I'm going to be alright.

I do not overcrimp. I open the mouth to .380 for seating and crimp to .378. The bullets fits into the shell before seating and luckily show no signs of scraping in most cases.

I use a Lee seating/crimping die. Setting the die to first seat and then crimp would be time consuming, although I could buy a second die and have each one do the separate steps. Something to think about. But scraping does not seem to be the problem. I pulled a couple of bullets and no scraping.

I set up for only one brand of shells at a time, even though looking at the headstamps there are differences that show the shells were manufactured on different machines. I am not going to start sorting the shells of the same manufacture.

I have tested the bullets for tightness and it seems fine. The mouth of the shell is .378, the bullet .357, shell thickness x2 is .020. I guess the shell holds the bullet just under the mouth of the shell.

I like a .378 crimp. The seating and crimping seem to go well with the Lee die, without scraping although 2 separate steps is a good idea.

I don't use U-dies but may run some bullets through a resizing die to check size. I don't use the FCD. There are lots of posts on their use, so lets keep that as separate discussion.

Now, back to my original problem of some scraping at the mouth of the case. Your suggestions got me looking for the problem more deeply. I think that some shells have a ridge just inside the mouth of the shell. Not in all shells, but a few. The ridge is no more than .001, but does show up in some of the bullets I pulled as a line around the bullet mouth. This line is from a few thousandths of scraping at the mouth of the shell. But when I pulled the bullet, there was no more scraping. I'm thinking the shell sprung back from crimping.

I took some pictures showing the ridge on the shell, the thin line around the bullet and a homemade chamfer that is just to remove the ridge and not to chamfer.

If I knew how, I would load them on this message.

I don't know if I want to add having to remove the ridge from the shells and an added step. I think I'll have to settle for less than a Perfect reload.

Edited July 25, 2016 by Wheeljack

[rowdyb]

any brass that has the "step" inside the case is garbage. throw that crap away.

[Steve RA]

A minute ridge inside the case mouth and a "stepped" case are two different things. The "stepped" cases should be sold for scrap, although some people use them for minor loads. Still a problem if it separates in the chamber during firing.

It has been reported that stainless pinning will sort of blunt the end of the case which would possibly make a minute ridge both inside and outside the case mouth.

[Wheeljack]

It seems my new SNS coated bullets may be softer than usual. Maybe. Whether I like it or not, separate seating and crimping seems the best way to go. I still get a slightly indented ring around the bullet when I pull them, but it does not break the coating or scrape it. Thank you all for the help.

Edited July 26, 2016 by Wheeljack

[7sst]

"I open the mouth to .380 for seating and crimp to .378."

If those are both outside dimensions, I'd bell the case quite a bit more. As others have mentioned, the crimp and seating in the same die may not be helping either.

[Dr Mitch]

It is the timing of the seating and debelling taking place in the seating die. You will need to experiment with raising/lowering the die body and readjusting the seating stem. Eventually you'll find a sweet spot, and never have problems again.

[Wheeljack]

I guess there are more ways than one to get the job done. We look for perfection in an imperfect world. Thanks all.

[HOGRIDER]

This process sure helped me overcome some issues with loading coated bullets:

http://forums.brianenos.com/index.php?showtopic=205711&hl=