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Nathan · October 30, 2011, 03:37 PM

First, let's talk ideals here. Ideally, you want the body of the case to be the fired size minus a very small amount to allow you to put it in the chamber again easily. You want the shoulder pushed back the same way. Next, ideally you want the ID of the neck to be aligned to the OD of the body. That will make the bullet more aligned with the centerline of the barrel. Last, you want the neck wall thickness to be exactly the same all around so it will release the bullet evenly, instead of off to one side.

This is all ideal and cases, chambers and even barrel centerlines may not be perfect. This is where you the reloader work to make it perfect. If your gun is nearly perfect, and your case is perfect, you actually don't need to size at all. This is due to springback. Only extremely precisely built rifles, cases and bullets can be adjusted like this.

A FL die is a 3 n 1 die. It sizes the neck, shoulder and body of the case. To make it 3 in 1, the maker has to guess how much you want resized relative to one another.

A collet neck die is a die where an outer floating collet sizes the neck down onto a fixed mandral. This has the benefit of resizing all or part of the neck to align with the ID of the neck.

A bushing neck die will size your neck like a collet die, but requires neck turning to be concentric since you're working the OD of the neck.

A body die will size only the OD of the body.

A shoulder bump die will just bump the shoulder.

If you push these limits, then you will need to move to a different type of dies and press because a standard press is axially only so accurate!!!

October 30, 2011, 03:37 PM	#9
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,331	First, let's talk ideals here. Ideally, you want the body of the case to be the fired size minus a very small amount to allow you to put it in the chamber again easily. You want the shoulder pushed back the same way. Next, ideally you want the ID of the neck to be aligned to the OD of the body. That will make the bullet more aligned with the centerline of the barrel. Last, you want the neck wall thickness to be exactly the same all around so it will release the bullet evenly, instead of off to one side. This is all ideal and cases, chambers and even barrel centerlines may not be perfect. This is where you the reloader work to make it perfect. If your gun is nearly perfect, and your case is perfect, you actually don't need to size at all. This is due to springback. Only extremely precisely built rifles, cases and bullets can be adjusted like this. A FL die is a 3 n 1 die. It sizes the neck, shoulder and body of the case. To make it 3 in 1, the maker has to guess how much you want resized relative to one another. A collet neck die is a die where an outer floating collet sizes the neck down onto a fixed mandral. This has the benefit of resizing all or part of the neck to align with the ID of the neck. A bushing neck die will size your neck like a collet die, but requires neck turning to be concentric since you're working the OD of the neck. A body die will size only the OD of the body. A shoulder bump die will just bump the shoulder. If you push these limits, then you will need to move to a different type of dies and press because a standard press is axially only so accurate!!!