difference in dies

[calixt0]

I bought a set of dies from Lee. It came with a full length sizing die, a collet neck sizing die and a length seating die.

Why would someone want to full length size and neck size? I'm just starting loading for an ar15 and wondering if I need both? I don't have a crimping die or room in the turret press so I was wondering if I should drop the neck sizing die and get a crimping die?

Just looking for advice?

[Javi]

I don't believe people neck size .223 for their ar-15's or other semi-automatics. That's more of a bolt-action process.

[Cowboy T]

Yep, neck-sizing's for bolt guns. A lot of folks get once-fired brass from wherever. It needs to be full-length sized first, to put it back to SAAMI specs. Then you fire it, and the brass fireforms to that gun's chamber. From then on, all you need to do is neck-size it. Not only will you get better consistency from your bolt gun, but your brass will last longer, too.

In semiautos like AR-15's, the round needs to fit into the magazine, and more importantly, it needs to be small enough to easily slide into the chamber at the high speed of a semi-automatic's action. That's why you need to full-length resize for semi-autos. You don't want jams.

As far as doing both, you don't. It's either one of the other, full-length or neck-only. For your AR, being a semi-auto, the neck-sizing die isn't the right application for you, so go ahead and get the crimp die.

[calixt0]

Yep, neck-sizing's for bolt guns. A lot of folks get once-fired brass from wherever. It needs to be full-length sized first, to put it back to SAAMI specs. Then you fire it, and the brass fireforms to that gun's chamber. From then on, all you need to do is neck-size it. Not only will you get better consistency from your bolt gun, but your brass will last longer, too.

In semiautos like AR-15's, the round needs to fit into the magazine, and more importantly, it needs to be small enough to easily slide into the chamber at the high speed of a semi-automatic's action. That's why you need to full-length resize for semi-autos. You don't want jams.

As far as doing both, you don't. It's either one of the other, full-length or neck-only. For your AR, being a semi-auto, the neck-sizing die isn't the right application for you, so go ahead and get the crimp die.

ok.. thanks. I don't need the neck size... do I need the crimping die or is it just spending more money.

[rsrocket1]

Ditto what CowboyT says. For a bolt gun where normally neck size only, every several shots (or when you notice that the bolt starts to encounter resistance to the case, you can use the full length die to "partially full length resize" and bump the shoulder back a couple of mils.

That's why it's good to have both dies with you all the time.

[NiteQwill]

ok.. thanks. I don't need the neck size... do I need the crimping die or is it just spending more money.

Crimping is a personal preference. Many do it, most don't. Some say lack of crimp has no effect on accuracy.

I don't crimp on my bolt gun.

I only crimp plinking rounds (Hornady 55 gr) both semi and bolt.

I don't crimp rounds for my service rifle (69, 75, 77, and 80 gr Nosler/Hornady).

[GeoffLinder]

In .223, crimping only works well when you have also trimmed the cases to uniform length. If they aren't the same length, the crimp won't be the same from case to case. Also, you should always taper crimp for .223, not roll crimp.

As far as increased accuracy goes, if you taper crimp (just lightly, not much is really needed) using same batch cases (so case wall thickness is similar case to case) AND have trimmed to uniform length, I have found that the crimp provides a slight decrease in SD (Standard Deviation) over the chrono. It is not something that you will be able to measure at 100 or even 200 yards, but whenever SD is reduced a bit, vertical stringing way, way downrange is decreased. I am talking 300-400 plus yards here.

As far as needing a crimp goes, you really don't IF your expander ball is at the right spec. A properly sized case mouth is just over a thousandth under bullet size, this interference fit is really all you need to hold the bullet well. Folks who find they have to crimp to keep the bullets in place are almost certainly off spec in their sizing to start with

[calixt0]

ok well I'll remove the neck size die ( I set it up because it showed it that way in the instructions for the dies) again I'm extremely green at this, and I'll leave it alone without a crimp for now. that just leaves me 1 empty spot in my turret i guess no harm in that. haha.

thanks guys.

[CEDaytonaRydr]

I don't believe people neck size .223 for their ar-15's or other semi-automatics. That's more of a bolt-action process.

Yes, and only if you're shooting it out of the same chamber it was fired from. The brass lasts a lot longer, though.

[Cheep]

I think the collet die you have is the CRIMPING die.

[calixt0]

I think the collet die you have is the CRIMPING die.

nope... its set up with the a decaping stem and everything... again the instructions that it come with clearly show a picture of it and its a collect neck sizing die.

However on the other hand I can use it and adjust it so that the collet makes the neck slightly smaller than the full forming die and it may have a similar effect.

[rsrocket1]

I don't think it will work properly that way. The collet crimp die (I have one for .308) puts a taper crimp at the top of the neck only. The collet neck sizing die squishes the entire neck against the decapping mandrel. You adjust the die in your press or push your press handle to give about 25 foot-pounds of torque on it. Any more pressure is useless because you are pressing the brass in the neck against a mandrel and the slots between the collet fingers won't close any more.

If you have a seated bullet already in the neck, the collet neck sizing die minus the mandrel will squeeze the entire neck against the seated bullet. That will probably swage the bullet thinner (and probably cause less neck tension if the brass is more springy than the bullet jacket+lead core)

[calixt0]

I don't think it will work properly that way. The collet crimp die (I have one for .308) puts a taper crimp at the top of the neck only. The collet neck sizing die squishes the entire neck against the decapping mandrel. You adjust the die in your press or push your press handle to give about 25 foot-pounds of torque on it. Any more pressure is useless because you are pressing the brass in the neck against a mandrel and the slots between the collet fingers won't close any more.

If you have a seated bullet already in the neck, the collet neck sizing die minus the mandrel will squeeze the entire neck against the seated bullet. That will probably swage the bullet thinner (and probably cause less neck tension if the brass is more springy than the bullet jacket+lead core)

all good points. what I was trying to say is in my set I currently
1: run a full length sizing die
2: prime and full case with powder
3:seat bullet
4: if i get a crimp die crimp

between 1 and 2 I can do the collet neck sizing die (according to the specs and instructions) I can set the collet so that the neck is tighter than standard and get the ideal fit the geofflinder mentioned of .001 smaller than the bullet diameter...

[NiteQwill]

You need to be trimming if you're full length sizing.

[calixt0]

You need to be trimming if you're full length sizing.

understood!