Issue with Dillon sizing die

[Bassguy]

9mm luger
Dillon 550B
Dillon dies, carbide inserts


I've set up the 550B and all dies as recommended. Specifically with the sizing die, I raised the shell plate completely and threaded the die, lowered it completely to make contact with the plate, and then tightened the lock nut.

Well, I ran a few once-fired cases through and the die only sized the shell about 2/3 of the way down the body of it. So, the upper 2/3 of the case is sized and slightly narrower than the lower 1/3. As I'm a novice, I decided to continue the process: I primed it, placed the charge, seated the bullet and crimped it. Now, the shell's diameter is larger where the bullet was seated and near the base of the shell, but in the middle 1/3 it's extra narrow. What the heck? Just to make sure it wasn't the brass, I tried it with a new case and got the same results.

I was sure to pull the operating handle all the way down...any chance the sizing die's insert is the wrong diameter? I was a little frustrated and so stopped and packed up right there for the day and didn't take the time to measure the resized case diameter (the thinner portion), but it definitely looks narrower than a new case to the naked eye.

Help?

 

[ReloaderFred]

Dillon sizing dies don't size down the case wall as far as most other sizing dies. The mouth of the die is flared to facilitate their use in Dillon's progressive presses. What you're seeing is pretty normal for their pistol dies.

This is one of the reasons I don't favor the Dillon sizing dies, even though I own a few. I prefer other brands that size down the wall of the case as far as possible.

Hope this helps.

Fred

 

[Bassguy]

Hey Fred,

It does help. Rather than replace that die, is there a way around creating this not-so-straight-walled case?

I'll see if I can get a pic posted tomorrow...

 

[Jim Watson]

Known as the Coke-bottle effect.

It won't hurt anything, I consider it a good sign that the brass is well sized down and the bullet unlikely to set back when it hits the feed ramp.
A different die with less mouth radius will just move the transition further down, nothing is going to size the bottom .125" of a case in a conventional press, and less radius means more hangups on a progressive.

Load 'em and shoot 'em.

 

[ReloaderFred]

Bassguy,

The 9x19 case is actually a tapered case. As long as the loaded rounds will chamber freely in your pistol, they're safe to shoot, even if they're not pretty.

Different sizing dies will have some variation in diameter. There's just no way to make mass produced tooling come out exactly the same. There is what is known as "tolerance stack" in manufacturing. Each tool is made within manufacturing parameters, or +/- a certain measurement. As long as the finished product is within those tolerances, then it's acceptable. What we sometimes run into is one tool at the minumum specification, and another tool at the maximum specification. They are both within spec., but the difference between them is the "tolerance stack", which in some cases can be a considerable difference, depending on the manufacturing specs. and allowable variation.

The reason I mention this is, if you have a die that was manufactured to the minimum spec., but within the parameters, and your brass has been expanded in a large chamber, the sizing is going to be much more noticable than if the die had been manufactured to the maximum allowable specification. Since the Dillon die is designed to size the portion of the case that actually holds the bullet, or the neck if you prefer, plus a small amount, then the sizing is going to be pronounced, but will probably hold the bullet well. You'll have to see if the rounds chamber and then go from there. If they will, go ahead and shoot them, but if they won't, then another sizing die will be called for, as long as the over all length is correct for your chamber and the bullet is off the leade enough.

Hope this helps.

Fred

 

[Bassguy]

Thanks again Fred and Jim. I think I'm just too used to seeing those pretty factory ammo cases.