9mm case bulge

[Crazy Horse]

I reload using a Hornady lnl AP press. Every so often I get a case that looks like this. Is there something wrong with one of the does (seating), or is it just the case that ended up that way after firing? It was a factory case and this was the first time used for reloading.

 

[Blue68f100]

Looks like your crimping and seating in the same die. I would suggest backing off the die body at least 1/4 turn. I suspect the case has a slightly longer length causing the problem. I use a separate TC die in station 5 to crimp.

Could also be a stepped case with bullet setting too deep.

 

[mrawesome22-250]

Speer case by chance? Had some Speer brass recently that had a ledge on the inside that did that.

 

[LiveLife]

Looks to me way too much crimp (As indicated by rounded case mouth) that pushed down on the case neck to collapse the case.

Measure the diameter of collapsed round at case mouth/neck and see what it is.

Since case wall thickness averages around .011" at case mouth, I usually add .022" to the diameter of bullet to return the flared case mouth flat on the bullet and hair more - https://www.thehighroad.org/index.p...nd-bullet-setback.830072/page-3#post-10712225

So for .355" sized bullet, taper crimp amount should be around .377" and no more than .378".

Looks like your crimping and seating in the same die.

I seat and crimp in same step using Lee dies and here's a finished 115 gr FMJ. Notice the sharp square of case mouth to headspace with chamber and even case bulging around the bullet base to indicate good neck tension that produces no bullet setback.

RMR 9mm bullets sized .3555" loaded with .378" taper crimp. Note sharp squared off case mouths.

 

[9mmepiphany]

My first impression was also that you are seating and crimping in the same die and applying too much crimp, way too early.

This can be caused by either die settings or varying case length...or a combination of the two

 

[TonyAngel]

Yep. Too much crimp. Seat and crimp using separate dies.

 

[LiveLife]

Seat and crimp using separate dies.

So I am doing something wrong?

I seat and crimp in same step using Lee dies

BTW, I did compare seat/crimp in same step vs seat and crimp in separate steps and for plated/jacketed bullets, no discernible difference, especially using .377"-.378" taper crimp for 9mm that moves very slight amount of case mouth while bullet is being seated.

 

[Texas10mm]

With straight wall auto pistol brass it's always better to seat and crimp in separate operations.

 

[TonyAngel]

I wouldn’t say you’re doing anything wrong. I’d just say that seating and crimping at the same time invites complications.

seating and crimping at the same station becomes less problematic if you ensure the uniformity if the case lengths, but who wants to do that? You have the space. Get a crimp die and make life easier.

 

[Walkalong]

Seater/crimper is likely set wrong. Or maybe you have a stepped case, but damage to the case mouth looks like you're way over doing the taper crimp. It takes very, very, little.

Yes, it's easier to seat and crimp in a separate step, but it isn't particularly hard to do it in one in an auto pistol caliber.

https://www.thehighroad.org/index.p...-and-crimp-in-two-stages.623417/#post-7699828

 

[rfwobbly]

Lee makes a separate Taper Crimp Die you can acquire for about $13.

https://www.midwayusa.com/product/1016834814

I'm not a huge Lee fan, but even I have to admit this is a superior product.

 

[LiveLife]

Wait, why are we talking about Lee dies and seating/crimping in one step?

OP is loading on Hornady LNL AP press with RCBS dies and did not mention whether seating and crimping were done in one step or separate steps.

This from another thread - https://www.thehighroad.org/index.php?threads/9mm-resize-die.863126/

started reloading with a Hornady LNL AP ... I purchased ... a set of RCBS dies for 9mm

Me mentioning my Lee dies was in response to member Blue68f100 who posted cause of collapsed case could be from seating and crimping in the same step and member TonyAngel who posted seating and crimping should be done in separate steps. And I posted my practice of seating and crimping in the same step using Lee dies ...

Looks like your crimping and seating in the same die

Seat and crimp using separate dies.

 

[Steve C]

Every so often I get a case that looks like this. Is there something wrong with one of the does (seating), or is it just the case that ended up that way after firing?

I have had cases do this and in trying to figure it out my conclusion is its caused when seating the bullet and you get brass flow as the bullet pushes to tightly or at an angle against the brass. I have observed the case bulge after loading an perfect normal case with a bullet that has greater than normal resistance to being seated or not started straight into the case. Often the extent of the bulging problem is seems to be associated with a particular brass and bullet combination.

 

[Crazy Horse]

Thanks everyone.

There's lots of experience on this forum, I can tell because I never mentioned seating and crimping with the same die. But many folks deduced that just by looking at the photo.

Yes I do seat and crimp with a Hornady die.

I have a separate Lee die just for crimping that I use with my turret press. And yes I never had this issue when the seating and crimping processes are separate. It never dawned on me until folks here mentioned it.

I used the crimp die on the Hornady press some time ago, but opted for seating and crimping in one station to open up a station for bullet feeding. I have since learned that bullet feeders don't work well.

I'll be adding the crimp die back as everyone has suggested.

I'm finding out that Lee dies are pretty good and very durable. Yesterday I replaced my rcbs resize and deprime die with my Lee resizer die. Today I'll be adding the Lee crimp die back. The only two stations not using a Lee product are the expand and charge station and the seating station.

Thanks again everyone and happy reloading.

 

[Blue68f100]

You can do it in 1 step. Just have to setup the dies correctly. Get the OAL set first then back out the seating stem, and adj the body for crimp. Remember the only function is to remove any expanding you did for the bullet to seat without shaving. Once set put the completed bullet back in and adj the seating stem down till contact. Now run and one through and see if every thing is good. Try to set the crimp using a piece of brass that is longer than your average length. This way when a long one comes through it does not cause the same problem.

 

[Crazy Horse]

Blue68f100,

THX

I tried several times, but it seems a bit difficult. I thought I had it, but from the looks of it, It's crimping too much. I may give it another try, but from the comments above, seating and crimping on the same die can be difficult to set.

I purchased the Hornady custom grade dies as it seemed easier to set the die to seat and crimp at the same time with those, but that hasn't been the case. It's youtube time for one more go.

If I can't get it though, I'm breaking out the Lee crimp die and just going with that.

 

[LiveLife]

You can do it in 1 step.

Try to set the crimp using a piece of brass that is longer than your average length. This way when a long one comes through it does not cause the same problem.

Very good point.

If you adjusted the taper crimp with a short resized case, a longer case will definitely apply more crimp.

 

[rsrocket1]

The good thing about 9mm is that there is so much laying around there is usually no problem coming home with more 9mm brass than you shoot. The problem with 9mm is the dimensions are all over the map. If the case length is a little too long and you try to seat and crimp in one step, you are trying to push the bullet deeper while the die body is already trying to crimp the case mouth. The LnL AP has 5 stations so there is adequate room to have both a case expansion die, seat die and a crimp die. I use the Lee taper crimp die to close the bell on my 9mm cases after seating. No need to get the case mouth much further than vertical to ensure it feeds smoothly and headspaces properly.

 

[LiveLife]

If the case length is a little too long and you try to seat and crimp in one step, you are trying to push the bullet deeper while the die body is already trying to crimp the case mouth.

This would occur if you were applying too much crimp.

With OP using plated bullet, essentially no crimp is required, just return the flared case mouth back flat on the bullet. And since case wall thickness averages .011", adding .022" to the diameter of the bullet accomplishes this.

And yes, you absolutely can seat and crimp in the same step (Been doing it for over 600,000 rounds) and with case mouth flare just going back flat or slightly more, the bullet seating downward won't affect slight case mouth movement inward and vice versa.

 

[tightgroup tiger]

Try to set the crimp using a piece of brass that is longer than your average length.

Hey Blue, don't you mean shorter than the average length? I find the shortest one I can find to set up with, that way I know I am removing 100% of the flare on all of them.

 

[LiveLife]

Hey Blue, don't you mean shorter than the average length? I find the shortest one I can find to set up with, that way I know I am removing 100% of the flare on all of them.

No, since OP is using a lot of crimp, using longer resized case to set the die would help not apply even more crimp.

If no crimp was applied and case mouth flared just returned to flat, using shorter resized case to set the die would be fine as slight crimp applied with longer resized cases would not negatively affect seat and crimp operation.

 

[tightgroup tiger]

Ok, I see your point of view but don't see why that much crimp is needed in the first place with a 9mm. He is topping out in his crimp and that's why he is having problems.

I must have missed something in the earlier posts.

 

[Crazy Horse]

The good thing about 9mm is that there is so much laying around there is usually no problem coming home with more 9mm brass than you shoot. The problem with 9mm is the dimensions are all over the map. If the case length is a little too long and you try to seat and crimp in one step, you are trying to push the bullet deeper while the die body is already trying to crimp the case mouth. The LnL AP has 5 stations so there is adequate room to have both a case expansion die, seat die and a crimp die. I use the Lee taper crimp die to close the bell on my 9mm cases after seating. No need to get the case mouth much further than vertical to ensure it feeds smoothly and headspaces properly.

Excellent point. The problem with 9mm brass is that it is SO close to 380. I've had two instances where after I finished reloading a cartridge, I noticed it was a 380 case. I reloaded it with no issues, only upon visual inspection did I notice the actual bullet seemed much longer than my other reloads. They also weigh less, so since starting reloading with the Hornady LnL, I weight each case and make sure it is within a specific range.

 

[LiveLife]

They also weigh less, so since starting reloading with the Hornady LnL, I weight each case and make sure it is within a specific range.

Wow, that's a lot of work.

I usually line up the cases on the bench top and use a ruler or something straight and shorter 380Auto cases are easily and quickly spotted.

 

[Crazy Horse]

Quick question, has anyone run into any issues not applying crimp to 9mm ammo? I typically load mine with 4.9 CFE Pistol for an estimated 1050 fps. That puts it on the low end of the Hornady reloading manual.

I've always crimped. When I was using my Lyman American 8, it was very easy to separate seating and crimping (8 stations). It also allowed me to apply a light crimp, which was easy.