Neck Expansion 101?

[Jaywalker]

Well, the Rockchucker Master Supreme kit came yesterday, along with the calipers I ordered to get started, but I'm still stuck on which dies to get to begin loading 6.5X55.

From what I've read, the critical part of accurate reloading is the neck expansion. If it's done wrong, the cases get off-center and also need to be trimmed more often. I'll be starting with Lapua brass, so I'd like to minimize die-induced distortion. Second, I'd like the bullet seated straight. While I'm not made of money, I'd just as soon pay up front for dies that will make me happy than to try to just get by with "good enough."

As to the makes, I think Redding dies are out. I have no way of specifying the right size of bushing - they assume you have a loaded round to measure and a micrometer to measure it with, and neither one of those assumptions is true.

Forster? All those benchrest guys must have a reason to choose them, but I don't have a feel for the "straight-line seating" techniques they use. Also, in my experience, things sold for specialty needs, like BR, usually have major drawbacks for people who don't specifically need to shoot "in the zeroes."

The Lee Collet dies have some good arguments, particularly the mandrell, but I don't understand the process. Doesn't the mandrell just limit how small the neck is sized? If the expander button is the real problem, how does the mandrell help?

As you can see, I don't understand a lot of this stuff, so I'd appreciate some facts as to how these things work. Thanks.

Jaywalker

 

[redneck2]

FWIW...

in typical neck sizing, the die squeezes the neck too much, then the expander opens it back up. On the collet die, the outside of the collet forms the neck around the mandrel. There is no expander button.

Problem with crooked necks comes from two sources. If you try to neck size only with typical dies, the case head may move in the shell holder. If the head is off to one side, it will bend the neck crooked.

Other is when the expander button is not round or off to the side (if the expander shaft got bent somehow for example). One brand of dies (RCBS?) has an O-ring that allows the expander to "float" and self-align. I've read that these can be added to other brands.

Good sources of precision info...Varmint Al's website, Handloader magazine, and Fred Sinclair's "Precision Reloading and Shooting Handbook.

For starters, I'd suggest a basic reloading book like Lyman's.

 

[Jaywalker]

redneck2:

in typical neck sizing, the die squeezes the neck too much, then the expander opens it back up. On the collet die, the outside of the collet forms the neck around the mandrel. There is no expander button.

Thanks, I didn't know that. With no expander button, It hadn't occurred to me that both new, unfired cases, and fired cases have necks that will allow a bullet to be seated.

If you try to neck size only with typical dies, the case head may move in the shell holder. If the head is off to one side, it will bend the neck crooked.

Didn't know that, either. That must be why the Forster (benchrest) dies are full-length.

O-ring that allows the expander to "float" and self-align.

I'd read about the O-ring, but not that it was a part of the expander shaft or how it related to off-center issues. I'd heard of folks putting them on the shell-holder, for instance, and didn't know why. Until you mentioned this, I assumed that the only off-center issue had to do with the expander pulling brass unevenly, not that the shaft itself was an issue.

I've been using the Lyman's 47th for six months, but there's no real discussion of die issues in it, nor is there with the Speer manual delivered with the Rockchucker. I've been to Varmint Al's, but for some reason hadn't considered it a source for basic handloading issues. I'll check it out.

There's lots of info here - I appreciate it.

Jaywalker

 

[Coltdriver]

I am a newbie to reloading too but another thing that I have discovered is that once you have fire formed your cases then neck sizing only is a good way to keep the neck centered in the chamber.

That being said I would not get all wound up about the redding bushing issues. As mentioned above the die squeezes the neck down and the expander button opens it up again.

What does happen, however, is that the necks get hard fairly fast. After four or five reloads it is a good idea to anneal the neck to soften them up again.

I bought a three die set of redding dies for .223 and have reloaded about 500 rounds with them so far. I was able to use these dies to dial in an excellent load for my Ruger.

Changing the bushings is one of those tiny details that you may want to consider after you are turning the necks and measuring case run out and using competition class dies.

 

[Delmar]

Jaywalker
One of the most important things you can do is to set your dies up properly in your press. Which ever dies you select will have a set of instructions with them and the set up varies with the mfr.

I have used RCBS, Redding (full length), Hornady and Lee (full length and neck sizing) and have had good results with most of them. I like the mandrel type neck sizers from Lee, but the others are pretty good too. The mandrels do not require that you lube the cases as the others do.

 

[mtnbkr]

I double size my brass with my Lee collet die. I run it through once, turn the case in the holder a bit, and run it through again. After that, I go to the next step.

The results for me have been good so far.

The target at the right is .264 at 50yds with a cold barrel
The target at the left is .4 at 50yds with a hot barrel and tired shooter

Chris

 

[Jaywalker]

mtnbkr, Why did you double-size them? (I'm so tired of your gnat-sized groups that I have to get you out to a range that you have to drive to place the target, like 300 yards... that'll open them up. )

Jaywalker

 

[mtnbkr]

mtnbkr, Why did you double-size them?

I can't remember where I read it, but I did read somewhere that double sizing (along with turning the case in the shellholder about half a turn) ensures that the neck is evenly sized around it's circumference and straight. Dunno if it really makes a difference, but it only takes an extra second of my time.

I'm so tired of your gnat-sized groups that I have to get you out to a range that you have to drive to place the target, like 300 yards... that'll open them up.

You and me both. I rarely get to shoot at longer distances. The few times I have shot at 100yds, I couldn't settle down and get comfortable enough to do well. I really need the practice.

Chris