9mm Case Head Separation

[W.E.G.]

That's produced by sizing an overexpanded case, and/or misalignment of the sizing die and the shell holder where the case is not perfectly aligned with the size die.

Definitely looks like some sort of turret-press fail.

 

[zeke]

Nice photo.

Before I used the Lee undersized, I had always used their standard and mine looked like this. (The cartridges not photos.) And I was a happy camper. No expanding/no flare either.

But I seemed to be getting some pretty easy seating and setback concerned me. That drove me to the undersized die.

When I say easy, I mean I couldn’t feel resistance as the bullet was seated. Not some, none. Again, in a non-expanded case I didn’t like that at all.

Now part of that was likely the Redding competition seater keeping the bullet straight. And probably the slickness of the .355” Extreme plated bullets contributed.

I also wouldn’t be surprised if some of the bullets were a bit undersized. Not sure about the latter but they certainly had an inconsistent ogive as seating depth wasn’t as consistent as it should be.

Ironically perhaps, I was about to be “forced” to go back to the standard sizing and/or expanding.

I just bought some new Berry’s .356” 115gr RN and not only are they larger, they’re apparently less slick with maybe thinner plating. Seem to have same degree of beveling. Try as I might, they would not seat without scraping off the plating even in a chamfered case. Got a few to work, but ruined 8 bullets experimenting. (And I’ve come to be really good at holding a bullet straight without pinching my fingers.)

Don’t see the point in under sizing then expanding back to accept a bullet. Why not start larger, I’m thinking.

Thanks for engaging and lending your expertise.

When i use the Lee u-dies, it is to "neck size" the brass slightly below where the base of the bullet would be. It is an extra step, but works for how i reload. Your brass looks very similar to what can happen to 45 acp brass over a longer period of time using regular carbide dies. Am agreeing that brass flows "gets pushed" down to the base. Easy to measure and compare against an unfired case.

 

[zeke]

That's produced by sizing an overexpanded case, and/or misalignment of the sizing die and the shell holder where the case is not perfectly aligned with the size die.

Am never assuming the sizing ring is concentric to the die, and use a fired case to "self align" the portion of the die doing the sizing, before locking it down. But am using a single stage.

 

[JJFitch]

Yes it does I just don’t want to unnecessarily contribute to it.

Funny I started out seeing how long cases would last and now that I may be finding out it’s not forever, I don’t like it.

You have discovered that yes there is a limit! I realize that not everyone can do this but I have 3 @ 5 gallon buckets each with 5-6 thousand 9mm cases almost all WW. I rotate through them so I'm into brass from say 20 years ago on the 3rd reload! Yes, I was on a Sheriff's team sponsored by Winchester! The only "ring" I've seen like that was from a defective size die that was replaced by the manufacturer. Since yours separated it's probably from overuse. And yes, I've seen case blowouts from "overpressure" cases, probably from a double charge!

 

[CQB45ACP]

You have discovered that yes there is a limit! I realize that not everyone can do this but I have 3 @ 5 gallon buckets each with 5-6 thousand 9mm cases almost all WW. I rotate through them so I'm into brass from say 20 years ago on the 3rd reload! Yes, I was on a Sheriff's team sponsored by Winchester! The only "ring" I've seen like that was from a defective size die that was replaced by the manufacturer. Since yours separated it's probably from overuse. And yes, I've seen case blowouts from "overpressure" cases, probably from a double charge!

Well I certainly don’t have that many cases but have multiple thousands. But I had been doing the grab bag approach (however systematic) and wanted to nail it down within reason for my purposes. I’m sticking with this batch until they’re reduced to brass dust but have gone back to the less extreme standard sizing die and am now expanding slightly because I just bought larger bullets (.356”).

 

[CQB45ACP]

When i use the Lee u-dies, it is to "neck size" the brass slightly below where the base of the bullet would be. It is an extra step, but works for how i reload. Your brass looks very similar to what can happen to 45 acp brass over a longer period of time using regular carbide dies. Am agreeing that brass flows "gets pushed" down to the base. Easy to measure and compare against an unfired case.

I certainly measure after each use, but haven’t planned a case “side by side” as shown in the Florida Reloading article. That is until now since I mentioned it

 

[zeke]

I certainly measure after each use, but haven’t planned a case “side by side” as shown in the Florida Reloading article. That is until now since I mentioned it

I never actually measured it, just observed a 1911 start to have difficulties fully chambering a round (45 acp) from heavily used brass. Then i looked closely (back when i could see alot better), and the base of the case looked larger in dia. Full length sized the brass, and the problem went away while bulge went away. One good thing about a LFC die is it sizes down further on the case base (at least on 9mm and 45 acp) than the standard resizing dies was using at the time. Now am using the modified Lyman die for 45 acp as previously mentioned. For the 9mm am using the LFC set to just remove any case neck expansion, but to resize as far down as i can adjust it. Where it resizes further down the base is easily visible. This works well since am using mostly jacketed bullets in 9mm. While am using more sizing steps than most, it suits my purpose for reloading large (500-1000 rd) batches.

 

[Barmcd]

Lot of information here to think about and I have no idea what caused that crack.

My observations

1. In my experience, my pistol brass does not get longer with use, it shrinks. I don't even measure it anymore.
2. I have 9 mm brass that I can barely read the head stamp on and it shows no signs of cracking.
3. I de-prime by hand and toss cases when it takes very little pressure to remove the spent primer. Most look very used, some look fairly new.

And a question. What's the purpose of an undersize sizing die?

 

[CQB45ACP]

Lot of information here to think about and I have no idea what caused that crack.

My observations

1. In my experience, my pistol brass does not get longer with use, it shrinks. I don't even measure it anymore.
2. I have 9 mm brass that I can barely read the head stamp on and it shows no signs of cracking.
3. I de-prime by hand and toss cases when it takes very little pressure to remove the spent primer. Most look very used, some look fairly new.

And a question. What's the purpose of an undersize sizing die?

Thanks

Well your question is a thread in itself

My answer is just mine--to promote greater tension on the bullet and/or accommodate a finicky firearm chamber.

 

[Barmcd]

Thanks

Well your question is a thread in itself

My answer is just mine--to promote greater tension on the bullet and/or accommodate a finicky firearm chamber.

I've heard of small base rifle dies, but didn't know they made an undersize pistol die.

 

[Jim Watson]

I use the undersize sizing die to bring the case down to where it has adequate bullet pull on short slick bullets like 115 gr plated or jacketed 9mm. I want to see that constriction under the bullet.
I do not use the U die for heavier bullets or coated lead.

 

[CQB45ACP]

I use the undersize sizing die to bring the case down to where it has adequate bullet pull on short slick bullets like 115 gr plated or jacketed 9mm. I want to see that constriction under the bullet.
I do not use the U die for heavier bullets or coated lead.

And to translate since I've asked you this before...bullet "pull" means the friction you get when using an inertia hammer. Correct?

 

[GeoDudeFlorida]

And to translate since I've asked you this before...bullet "pull" means the friction you get when using an inertia hammer. Correct?

More like the ability to resist inertia, regardless of the source.

Think about magnum revolver cartridges locking up the action because of bullets pulling under recoil, impacting the frame or forcing cone. That’s the most obvious example I can think of.

 

[Jim Watson]

I don't know if the manufacturers fool with it any longer but Bullet Pull used to be measured in pounds force required to pull a bullet out of the case.
My actual application is to prevent bullets setting back in the case when hitting the feed ramp. I have also applied a cannelure in the brass at the base of the bullet like some factory loads, but my tool for that requires a single stage press and a "U" die works in the progressive.

I have not had a problem with bullet pull from recoil in a revolver, but have heard of it.

 

[CQB45ACP]

Okay both of youse guys Is there a way for a layperson to measure it? Think I've asked this before too and answer is no? Other than number of whacks?

 

[Jim Watson]

I am satisfied to be able to see the constriction. A push against the bench edge is all the measurement I do.

 

[Tilos]

I am satisfied to be able to see the constriction. A push against the bench edge is all the measurement I do.

Pushing it against a common bathroom scale will give you a measurement for comparison.
jmo,
.

 

[CQB45ACP]

I am satisfied to be able to see the constriction. A push against the bench edge is all the measurement I do.

Yes me too but like number of whacks it's not much. BTW whether standard or under, for 9mm, always just one whack is my experience. Pushing against bench pretty much feels the same to me most of the time.

 

[GeoDudeFlorida]

Okay both of youse guys Is there a way for a layperson to measure it? Think I've asked this before too and answer is no? Other than number of whacks?

I use an FCD and trust in it to impart the correct neck tension for me.

 

[CQB45ACP]

I use an FCD and trust in it to impart the correct neck tension for me.

Did I tell you we made shrimp gumbo and the FCD ensured the ingredients stayed mixed perfectly?