Decided to trade in my cheap Lee RGB dies for the Lee Deluxe set with a collet neck die.

Want to see if I can achieve 1/4 MOA with my Stevens 200. What a wonderful rifle.

Will sizing with a neck die produce different pressures than a FL die?

I dont think it will change peak pressures but it will change the curve as to how quick it reches the peak. If you are loading with the bullet into the lands pressures may peak a little higher. you will need enough bullet gip so the powder you are using can burn complete.
I gennerally shoot for about .002" for target loads. loading single shot.
Dave

Couple of things on the Lee collet die. First, the neck tension will be about .002. The size of mandrel determines this and I don't know of anyone who offers interchangable mandrels for the collet die. Second, the die is set up for only a partial stroke of the press handle. There is a positive stop when the brass meets the mandrel and the handle won't go any further. If you try to continue the stroke something will break. Third, this die will load the most concentric ammo I've ever loaded. T.I.R. is always less than .002. And last but not least, this die will not get a 1 minute rifle to shoot 1/4 minute.

If anything it will decrease it slightly but by so little it will barely be discernable. I'm not a big fan of the collet die used by itself. I usually find with warm hunting loads I will feel bolt tension when closing the bolt and I do not like it for hunting loads. Also... at the bench I usually find that in my guns with ammo loaded exactly the same but the only diff being bolt tension when closing, and ammo with the shoulder bumped about .002"...the bullets will go to 2 different points of impact and there is not an increase in accuracy.
Since in hunting rifles I am looking for field usable loads only I do all my experimenting with the ammo set up with .002" spare headspace.
So, I am slowly converting my favorite calibers to using the lee collet die in conjunction with a redding body die.
BTW if you need more neck tension you can put the collet die mandrel in a power drill and sand it down slightly. Another good way of increasing grip I have found is to take a bore brush of the same caliber and put it in a drill and clean out the inside of the case neck really good. This leaves tiny swirls inside the neck which seem to increase the amount of pressure I need when seating.....it would be my opinion it gives more grip at "release time".
BTW I would not expect better accuracy out of the collet die unless you are getting really bad (>.005") runnout with the regular dies...but if you do.....good for you.

quote:

Originally posted by kraky:
If anything it will decrease it slightly but by so little it will barely be discernable. .....

I missed that the first time - you say "decrease it slightly"? Would that be because the bullet doesn't 'hesitate' on entering the rifling?

With my hornet and Lil'Gun, reducing neck tension reduced the pressure signs on the primer. But then, we are talking a weird situation here. Increasing the charge to the extent where it was 'properly compressed', improved accuracy and apparent pressure consistency signs on the primers. The barrel also ran cooler with more powder - go figure!