Lee collet neck sizer die

Hello all, I have what may seem like a really dumb question, but here goes anyway:

I've been looking at the Lee collet neck sizer die for .303 British. What I'm wondering is.....could a guy insert a boolit into a fired, unsized case, and then use the Lee collet neck sizer with the mandrel removed, to impart just a bit of neck tension to the boolit? Sorta very lightly crimping the whole neck onto the boolit itself? Or.....am I just some kinda crazy nutjob who shouldn't be allowed to be around reloading equipment?

Scotty

You probably could, but unless you applied the same force to EACH case the results would be erratic.

The idea behind sizing a case is to make it a little smaller than than the bullet. The bullet is then pushed in to the case causing it to expand. The tension between the smaller case and larger bullet is what holds it in place.
For extra protection it can be crimped into the crimping groove or cannelure.
When sizing the case against a mandrel the case actually springs back a little bit, it will not be the same exact size as the mandrel. So, if you were to size against the bullet there would be little, if any, tension to hold the bullet in place.
Hope this make sense.

Like post #3 said.. Brass springs back more then lead. This would leave a loose bullet moving around in the neck.

I've ordered custom Lee Collet neck sizing dies. To make the die, they ask for a sample bullet you would be using and sample brass. In my case, I sent them a .312" Hornady 174gr FMJBT bullet and Norma cases. And so, the mandrel is probably slightly smaller than .312" and the neck case thickness is taken into account. Previously, I owned a custom die like this and tried resizing LC brass that had a thicker neck. The mandrel got stuck in the case and I ended up damaging the die. This just tells me that the die is made to specific dimensions. I don't think your mandrel can be removed. Even if you could, I think it would swage your bullet. I would suggest trying a mandrel to expand the neck to vary neck tension and skip the crimp. I will do this on future testloads

Sounds like you want to use your collet die like a factory crimp die. Simple answer....I don't know if it will work or not. If it was me, I would try it.

I'm using my Lee Loader right now to neck size .303 British brass, and it is a bit over-zealous for paper-patched, non-gaschecked boolits. I really have to flare the case mouth like crazy to get a boolit in there. I'm having OK luck with just not even sizing the case at all, just flaring it a little and giving the case mouth a firm crimp with the Lee Factory Crimp Die. I guess, for now, I'll just keep going with that. Thanks!

Scotty

The nice thing about the Lee collet neck sizers is the amount of tension you want is controllable by how far in you screw the die. I use my collet sizer to about .314-.315 for .316 boolits. For extra measure I just rotate the case slightly so the 4 “teeth” of the collet get all around the neck.

It’s a very handy method that I use for other calibers as well.

Also another reason to buy one in 303B is for 30-40 Krag with oversized boolits. A 1-2mm washer around the base above shell holder and you can neck size the Krag brass to .310-312 if so needed.

Quote:

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Originally Posted by scottyp99

I'm using my Lee Loader right now to neck size .303 British brass, and it is a bit over-zealous for paper-patched, non-gaschecked boolits. I really have to flare the case mouth like crazy to get a boolit in there. I'm having OK luck with just not even sizing the case at all, just flaring it a little and giving the case mouth a firm crimp with the Lee Factory Crimp Die. I guess, for now, I'll just keep going with that. Thanks!

Scotty

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Try neck sizing only with an 8x57 die. That trick worked for me when I was experimenting with some .316 soft lead boolits.

The neck sizing die has a steel mandrel/decapper inside of it. It is about 2 thousandths smaller in diameter than nominal bullet size in order for the case mouth to end up somewhere around 1 thous or less smaller than the bullet. This is where you get your neck tension. If you tried to size it with the bullet instead of mandrel, you'd never be able to create neck tension. But you would be able to destroy it.

This is the reason the Lee FCD for pistol calibers is hot garbage.

The reason the Lee Factory Crimp dies (for rifle) work AFTER the bullet is seated is because the bullet already has neck tension. And the FCD only crimps the very end of the case mouth into a bullet that already has a crimp groove for doing this. Or in a bullet with no groove, it will remove any case mouth flare without disturbing the majority of your neck tension. The way the FCD works takes out any variation from case length. It leaves the same amount of neck tension, regardless, and the variation only affects the distance of mouth that gets crimped.

The mandrel in a LCD is removable. You could contact Lee and see if a larger diameter mandrel is available.

I needed a mandrel 1 thousandth smaller for my 22-250 and they obliged me for a few bucks.

Try here: https://leeprecision.com/custom-oversized-mandrel.html

See in the cartridge selection window that 303 British is listed as available

Enjoy

Three44s