Why do my cases have ripples?

[rsmith99]

I am reloading .357 using Redding dies on a Dillon press, using Redding dies. The brass is new Starline brass.

When I seat the bullet in the third station I see a couple of ripples in the case. Like the case is being crushed.

I am crimping on the fourth station.

If I use old Winchester brass I do not have this problem.

 

[hutchman]

I had the same issue with Starline 357 when new. However, I was seating and crimping with the same die. Changing to a separate crimp die fixed the problem. I do remember though that even when using the same die for both seating and crimping, used brass did not have the ripples.

Since you are already using separate seat/crimp dies, I guess I'm not much help. The only other difference was that I used RCBS dies......

 

[Rclark]

What size bullet? 158g, 125g?

Do you get this when you don't crimp? Could be over crimping. You don't need a lot of crimp.

You are using the expander die? You are are slightly flaring the case mouth?

You should NOT be seeing ripples at that spot if using normal length/weight bullets. You will usually see a slight ripple at the 'base' of the where the bullet is seated but NOT below that point. If you do something is wrong.

 

[rsmith99]

158gr. The ripple is coming from the seating die.

 

[Rick Courtright]

Hi,

Without actually being there to play w/ your components and dies, I'd suggest you start by measuring the bullets (most likely .358"--normal size for cast) then add some flare so the bullet drops in just a hair deeper before it encounters any resistance from the case. I've run into ripples like that when the bullet couldn't "self-center" first and got started in the case crooked. A little extra flare ended the problem.

That's the best I have for now...

Rick C

 

[Iron Mike Golf]

Expander might not be getting deep enough. A little extra flare, like Rick C suggests, gets you a little deeper expansion.

You might compare the length of the narrow part of the expander to how much of the bullet goes into the case.

 

[Jimbo357mag]

Be sure to size, expand and flair new cases. I bet you didn't get the expander plug down in the case far enough or that new brass is really soft or your bullets are a little oversized. The Lee FCD (factory crimp die) has a carbide ring to post size the completed round to eliminate that kind of thing.

 

[rsmith99]

I am using an expander from Powderfunnels. It's a universal expander and "stick" in the case like the othe expanders I used.

Like I said, I didn't have trouble with Winchester brass. I think the Starline brass is weaker.

 

[GP100man]

Not sure from the angle but I think I see lead being pushed up into the crimp groove ???

Anyways ,ya gotta start with consistent length brass .
Expanding is necessary especially for the softer 8-10 bhn boolits, flare enuff not to scrape any lead .
Lymans "M" die is made for cast boolits & the problem ya having .

Seat the boolit until the crimp groove is almost covered .
Now raise the seater plug up out of the way & adjust the crimp accordingly.
Lite for fast powders/plinkin ammo , heavy for slow powders
Now raise the crimped round into the die & run the seater plug to the boolit .

This generally works ,but there`s cases it won`t .
Such a case is the varying amount of force needed to seat a boolit & if ya have rounded noses or very soft noses they can be deformed if the correct seater plug is`nt used .
For this reason I mainly stay with SWC, RNFP designs . I only have 1 RN mold a Lyman 358311 & I have the seater plug for it also .

Next is the case itself , wall thickness , different rates of elasticity, & work hardening/brittleness .

This we have little to no control over & deal with anyway we must .

I use a vibratory case cleaner & while the outsides are shiney I`ll admit the insides leave a little to be desired & every other firing I spin a bronze brush in the necks to clean the left behind carbon/lube residue so as not to give problems seating .

I`ve even went as far as to anneal cases for straight walled revolver.
Here`s a batch I did a few weeks back .

I shot these until I had hi ESs on the chrony ,then annealed & rechecked .
They fell rite back in line as when new !!

Look close to see the discolored part , it takes alot less heat than ya think to relieve the stresses in brass.

PS: can ya stand a case up & take a pic & nice pic by the way , macro setting ???

GP

 

[Mobuck]

One of two things wrong here.
#1: Over crimping or the crimp is missing the groove in the bullet.
or
#2: You adjusted the crimp with a shorter length case and the rippled ones are longer.
The case is being telescoped shorter because it has no where else to go during the crimping stroke.

 

[rsmith99]

The seating die is causing the ripples. It is a Redding die and does not crimp.

 

[Iron Mike Golf]

I'd call that PTX a flaring tool not an expander. The area of the case that is south of the lube groove is being expanded by the bullet, not the expander, when the bullet is seated.

Here's a pic from another forum of a 45 ACP case (over)flared using a PTX:

Note that the case wall is not expanded. Only the case mouth is affected.



With the expander that comes with a die set or an M-die, the expansion from freshly resized to assembled dimension happens in 2 passes. First is by the expansion die. Second is by the bullet. With the PTX, it looks to me like the bullet does all the work of expanding the case, and doing it in one pass is too much for the brass. I wonder how consistent the neck tension is.

I have had that sort of thing happen if I have an expander set too shallow (or use a 45 AP spud for a 45 Colt cartridge).

edited to add: It might be more a matter of differences in case wall thickness than strength. A thinner case wall would have a larger inside diameter and be less prone to collapse. In this case (no pun intended), weaker might be better.

 

[AUSSIEBOB]

You will find that the case thickness with starline cases is the cause
I also get the ripples in 357 and 32cal and again only with starline.