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Full length sizing VS neck sizing
- Thread starter sniperjwt
- Start date
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QuietTexan
Well-Known Member
How sure of that are you? Per Lee's website they still make them and the current lead time is 6 week. They still make custom FCD dies also, I emailed them about it and ordered one recently from them.
Custom Undersized Collet Necksizing Mandrel
Custom Undersized Mandrel, please specify how many thousandths under the standard mandrel you would like it undersized in the box below. Current lead time is 6 weeks.
last I heard they stopped for now.... but that was a while ago. Just went on thier website and see you can order one. The one that comes with the .30-06 mandrel is .306 and I want a .307. I tried it with round stock to .307 but the collet didn't compress to the mandrel and didn't size it like thier mandrel. So it appears you need to open the slots on the collet to work right.How sure of that are you? Per Lee's website they still make them and the current lead time is 6 week. They still make custom FCD dies also, I emailed them about it and ordered one recently from them.
Custom Undersized Collet Necksizing Mandrel
Custom Undersized Mandrel, please specify how many thousandths under the standard mandrel you would like it undersized in the box below. Current lead time is 6 weeks.leeprecision.com
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Clem Bronkoski
Well-Known Member
I'm still trying to grasp this concept. What I'm imagining is that you remove the expander ball from the sizing die then run the case through the FL sizer. This brings the case, including the neck, to the proper SAAMI specs. Then you run the case again through a neck sizing die with an expander ball which the ball enters the case mouth, opening it up a bit then the neck sizer brings the case back neck back down to size and when the case is withdrawn the ball again expands the case mouth to accept the bullet. Is This what is happening or am I still at sea?
No it does it is way undersized without the ball expander. You want to eliminate using the ball expander all together even in the neck die.
Clem
You aren't out to sea. Once you have run the case through a FL resize die, as opposed to a body die, there is less than ZERO to be gained by running it through a neck die afterwards, whether there are expander balls in place or not. Neck size or FL size but no point in both. Body die followed by a bushing neck die, or collet neck die, does make sense to me.
You aren't out to sea. Once you have run the case through a FL resize die, as opposed to a body die, there is less than ZERO to be gained by running it through a neck die afterwards, whether there are expander balls in place or not. Neck size or FL size but no point in both. Body die followed by a bushing neck die, or collet neck die, does make sense to me.
No Sir. I use a Redding body die, sizing the body and achieving shoulder bump of .002". I then use a collet die with mandrel to "squeeze" the nick to a .002" inside friction fit on my bullet. Example: My bullet is .284" diameter. My preference is .002 seating tension, so I use a smaller mandrel, which allows for about .001-.002" springback. For MY needs and MY preferences, I use a .280 mandrel, which gives me about a .282" case mouth after sizing, accounting for springback.
In the past, I did use standard FL dies with the expander removed. Many still do. The removal of the expander prevents the expander from "pulling" your case neck/shoulder bump out of shape and thus potentially ruining your shoulder bump. Then you would use the die with the mandrel, which yes, the mandrel will open up your neck, but then when neck sized the neck will be set at or near the mandrel size.
Either way is a means to prevent the shoulder bump distortion by using an expander ball. As with all reloading, consistency and repeatability are the goals. Even if you achieve .003 or .004 neck tension, as long as they are all the same (or very close) then you are minimizing variances in shoulder bump, which can affect accuracy and brass life.
In short, the avoidance of shoulder bump distortion once the bump is set with the FL die, along with consistant neck tension are the ultimate goals.
Mikecr
Well-Known Member
This is what I don't like there, and I'm telling you, FL sizing of necks is a horrible thing to do. There is nothing 'good' in that.
Why not just use a body-bushing die (commonly misnomer'd as FL die) with it's expander ball removed. Then followup with a mandrel die.
That's 2 separate actions.
You could use a body die, followed with a bushing NS die, followed by a mandrel die.
That's 3 separate actions, but it's also ultimate control.
Why not just use a body-bushing die (commonly misnomer'd as FL die) with it's expander ball removed. Then followup with a mandrel die.
That's 2 separate actions.
You could use a body die, followed with a bushing NS die, followed by a mandrel die.
That's 3 separate actions, but it's also ultimate control.
QuietTexan
Well-Known Member
What you're missing is total movement of the brass, inwards and outwards.
Start with a regular FL die. Say the brass moves inwards 0.005" when sized down because the neck dimension inside the die is very small to ensure it sizes every case that goes in to the die is sized, then the expander pulls back through and moves it 0.003" out. Resulting neck ID is -0.002" under caliber. Total movement - 0.008".
Now switch to a bushing-body die. You pick the correct bushing and the neck moves in 0.002" and then the expander only pulls it back out 0.001". Resulting neck ID is -0.002" under caliber. Total movement - 0.003"
Next refinement, you use mandrels instead of the expander ball. Mandrels come in half-thou (0.0005") increments. Bushing sizes down 0.002", mandrel upsizes 0.0005". Resulting neck ID is -0.0015" under caliber. Total movement - 0.0025".
You can go to a -0.001" bushing and get the neck ID to -0.0005" and total movement of 0.0015". But in my world that's a little light in terms of holding the bullet. Realistically no way to move less in and out anymore.
Enter length of neck sizing. Neck of our hypothetical case is 0.260" long. An FL die will size all 0.260" of it, because the die is a single cut of metal so there are no gaps where brass isn't resized. Bushing die will size 0.210" of it, because a bushing die generally always leaves a small unsized portion of the neck. Then you back the bushing out (say with the mic on a Redding Type S Comp Neck Sizing die) and you can size all 0.210", or half at 0.130", or two-thirds at 0.174". Total movement still 0.0025" in and out, but less of the beck is moving. Less length of neck sized = neck has less grip overall on the bullet, but the part that's holding can hold tighter than if you set the entire length of the neck at a lighter setting.
Total movement of the neck is what results in work hardening. Total movement can also result in permanently yielding the case neck to where it acts differently than it did before.
Chamber diameter comes in to play here also, how much the neck is expanding when fired and what diameter it returns to, then is sized down to, then is expanded to by a mandrel, then ultimately by the bullet.
If you are referencing my last post, that is exactly what I do.
QT I admire your OCDness. No way am I doing all that dicking around to size a case. I run them through a collet die, neck die or bushing neck die and load them. Loaded they do better than .5, so close enough for the girls I go with.
Clem Bronkoski
Well-Known Member
Well it seems you're stating exactly what I was saying. You're basically working the case neck in and out a couple to 3 times using a FL die, a neck sizing die and a mandrel. Doing this and firing the case (like you said depending on how much room is in the neck of the chamber) you better be annealing your cases or they will be short lived.
QuietTexan
Well-Known Member
All it is is setting up a die once, I don't see why people think it's so hard. Buy brass, measure brass, set up die, use for the life of the barrel.
Not a big deal at all. Only takes maybe 300 more brain cells than spinning an FL die until it touches the shell holder.
