Bullet Seating Die is damaging case necks

[Dr Spin]

I have just started reloading .375 H&H Magnum cases with my Lee reloading press and dies. I have no problem with the Full length sizer but when I tried to seat the bullet with the Dead Length Bullet seating die the case became tight about halfway into the die and I could feel the bullet starting to be seated early.
I removed the seating screw and collet and pressed a sized but empty case up into the die. As the case reaches the top position the neck fits through a hole which I assume holds it completely central. This hole must be slightly smaller than the case neck because I have to increase the force on the handle. Examining the case I find that this has reduced the diameter of the neck from the tip to about half the way to the shoulder and is also taking a silver of brass off the top edge off the neck. I also notice a bright shiney ring around the base of the cartridge just above the rim.
When sizing I have followed the Lee instructions and screwed the sizing die fully down and a quarter turn more and the bullet seating die fully down and a half turn up.
The only thing I can think of is there is something wrong with the dies?

I have used privi partisan cases but it does the same with Ruger ones as well.

I would be very grateful if someone could shed some light on the problem please?

Regards John

[rwilson452]

The bullet seating die should be run down until it just touches the case. Then back it out 1/2 a turn. Not run all the way down.

[DiscoRacing]

did you check the case length... if they are not trimmed, they may be too long and hitting the top of the die

[steve4102]

The bullet seating die should be run down until it just touches the case. Then back it out 1/2 a turn. Not run all the way down.

The Lee "Dead Length" seating die is set up a bit different. From Lee.

Dead Length die adjustment

Make sure that you have the bullet seating die adjusted down so that the shell holder contacts the base of the die when the ram is raised to the top of its stroke. The Deluxe die set comes with the Dead length bullet seating die, which does not crimp the case, and is designed to be adjusted that way to eliminate clearance in the press for a more uniform bullet seating depth.

[jaguarxk120]

I would be careful setting that die up as new replacement brass runs about $1.10 for Remmington to $2.50 for A-Square each. It won't take long to pay for a new set of dies that work if you keep squashing brass.

[Dr Spin]

Here is a picture of a couple of the cases as you can see the neck has been reduced in diameter for about half of its length and you can make out a bright brass ring around the neck.

The case length is less than maximum 2.850 in and I have used a Lee Case Length trimmer. I have screwed the die into contacting the shell holder than turned back a half turn. Correction the instructions say it is just a normal Bullet seating die and not a dead length one.

[Dr Spin]

I have taken a factory made cartridge and pushed it into the bullet seating die. It comes to a stop with the case sticking out about 0.4 inch. The case shell holder takes up 0.1 inch so I make it that that I have 0.3 inch too much length to be accounted for?
Am I missing something?

[Brian Pfleuger]

Have you measured the diameter of the necks after sizing to be sure that they are within spec?


Edit:

Something is seriously out of whack with that die.... I just checked a fired and unsized case in my 7mm-08 Dead Length die.... I fits just fine, all the way up.

Take it apart and check for an obstruction in the neck area.... otherwise, I'd guess that the didn't final machine that die or something.

[mrawesome22]

Correction the instructions say it is just a normal Bullet seating die and not a dead length one.

Then set-up is different. For no crimp, take the die out. Run the ram all the way up with a empty case in the shell holder. Screw die down until you feel it contact the case. Back off die one half turn. Now you're golden.

[Dr Spin]

I would like to thank Rwilson252 and Mrawesome22 they both hit the nail right on the head. It just the penny didn't drop straight away.
The problem was my other 4 calibres were supplied with Dead Length seating dies and my new .375 has a Bullet seating die. I am used to screwing the die down until it contacts the shell holder. I was also reading one of the wrong instructions for my other calibres! As the two gentleman have said for the bullet seating die you only have to screw the die down until it contacts the top of the cartridge. This die is designed to put a crimp on the case or you wind it back up half a turn to stop the crimp. It must be this portion of the die that is damaging the case neck as I am pressing the cartridge too far into the die.
Mystery solved, thanks for all the help and I have learnt a valuable lesson and only spoilt half a dozen cases. I was very worried as a .375 is not a cartridge you want to get wrong!

NB In England the term for someone who does a trick like this is a "Numpty"!