I found a problem with my Lee Bullet Seating Die today and it may affect all that own this particular die.

Reloading some 6mm Nosler 70gn B/T's and found I was getting COL differences of up to .007 when measuring from the bullet ogive.

On further investigation I found that the B/T's polymer tip was bottoming out in the seating collar and therefore the bullet was being seated by the tip and not the ogive as it was designed for.

The differences in measurement appear to be a combination of 2 things:

The slight but differing lengths of the polymer tip.

The differences in compression of the polymer from slight variances in the pressure required to seat the bullet.

I haven't come across this problem before as this is the first time I have loaded B/T's in 6mm.
Not sure if it affects other calibers.

Got around it by machining the seating collar a little deeper while retaining the angles as best I could.
I finished the inside of the collar with a good polish job and now all my cases loaded with this bullet are within .0005 in length.

This problem may already be common knowledge or it may be an isolated case, but I thought I'd better share it with you just in case some of you can't figure out why your B/T's aren't grouping the way they should and you are using a Lee Seating Die.

Cheers
Boof......

my .243 lee seating die was pulling the plastic tip out of 87gr hornady v max bullets. they would hang up , and pull out.
any tips to polishing it?

I once had a problem with a Lee seating die. I contacted Lee and they sent me a new collet (collar?) that solved my problem.