Crooked seating

I have a Dillon SDB that I have had for some time, maybe 12 years.  Had the frame crack a couple of years ago and they took care of that.  I have always used the supplied seater for SWC bullets and adjusted accordingly.  I purchased a custom seater from the gentleman on ebay who makes them.  When I tried the new seater I could definitely see that the rounds were seating just slightly crooked and there was an unusual amount of lead being shaved from the bullet.  So, I adjusted the flare until that went away.  It took a good bit more flare.  Could it be that the sizer die is sizing down too much causing the bullet to seat crooked?  

I remember a guy on the old list saying he used a .45 colt sizing die, could that be a remedy for the crooked seating?  I have thought of getting a powder drop custom made that mimics the lyman m- die.  I have heard that it helps with straight seating of the bullet.  I have also considered shims under the bolt that holds the shell plate on to take up some of the slop. 

Any help would be appreciated.

Mac

I would contact that ebay seller.  If you have to bell the case more than you should (which isn't much) and it still looks like it's seating crooked, I would say there is a problem with the way that die was machined.  There should never be any lead shaved during seating.

That's what I thought, why am I having to bell more than normal.  Looking at a loaded round, it looks like one side is deeper in the case than the other.  The difference is small, but you can just see it.  I do have another seater if anybody has a lathe and can turn one.  I mention the .45 Colt sizing die because of another thread on here.  The author stated that it sized down to .470 instead of .466/.467 like the acp die.  My thinking is that this particular seater and the standard sizing die are the reason for the crooked seating.  Like maybe the way it seats in a straight line as compared to the regular seater does.  I am going to order a colt sizing die from Dillon and see how that works.

Mac

Is this a shoulder seating die, and did you change anything else on the press?

Yes, it is a shoulder seating die.  Sorry, I forgot to clarify that earlier.  I have not and did not change anything other than the seating die.  That is what is frustrating me.  I really like the die.  It looks 1st class all the way.  Maybe it's just my press.  It seats straight with the factory seater, but crooked with the other.  So, I'm using the factory one.

Mac

Just a thought, but I suspect that the shoulder seating die, which presses down around the shoulder of the bullet may be exposing a misalignment of the die in relationship to the base plate.    The factory die that seats on the nose of bullet, presses down on only one point, and may not expose the misalignment.

Good point.  I'm just going to stick with the factory seater.  The ammo is accurate with the factory seater.  When I finally step up to a 550 or a LnL progressive I try again, I have one for regular dies as well.

Mac

Since the goal is accurate ammo,  I think that is a good plan.  The only advantage of a shoulder seating die, is if you use two different lead bullets, one for the long line, and one for the short, as I do, you dont have to continually readjust the seating depth on your press.  

The shoulder seating die, does tend to collect lube at a faster rate, and I pull it and clean it about every three hundred rounds,

I have used a colt 45 sizing die, didnt like it cause it didnt size the case enough imo, but it did work and the bullets shot, i just didnt feel i was getting the amount of bullet hold i wanted,.

Did you compare accuracy of rounds loaded with each? You may not be seeing the misalignment with the first die, but it could still be there.
After you expand and flare the case, what is the case ID below the flare? It should be 0.001-0.002" less than the the bullet OD. If the case ID is smaller, you may be swaging your bullets down in diameter or the bullet may be pushed crooked by the tight case and bulge the case where the walls are thinnest.
I have a shoulder-seating stem in my press and it does help with bullet alignment. Pushing down at one point means the bullet can move where it wants to--and that may not be straight down.
I personally think too many people see expanding as ONLY being the flare operation and ignore that the case itself needs to be properly expanded for proper bullet fit.
Often if you pull a lead bullet, you will find that no matter what the original measurement were, the difference in the bullet OD where seating and the case ID where the bullet was seated is now only 0.001"--which mean either the case was expanded as it should have been before bullet seating or the bullet has been swaged down is size (a bad thing).

I know I'm a little late on this but maybe it will help someone else out.
I made my own shoulder seating die by taking a .372 diamater carbide drill bit, a vise with jaw pads and a variable speed drill to lengthen the nose cavity in the seater stem.
I have 2 Dillion SDB's a 450 converted to a 550 and a 550, the SDB seater plug is aluminum and you have to be carefull not to go too far, on the SDB seater plug you have to use a camfering tool like the one for camfering case mouths after triming to get clearance to seat on the shoulder of the LSWCHP 185 Zero bullet, you also have to check that the face of the seater plug is square mine was not and I had to square it so it would seat the bullets straight. The steel seater stems in standard dies is just a easy drill to depth required to fit the bullet nose to shoulder. I've done one SDB and one set of RCBS dies this way and they work perfic.
The carbide bit I used was the chisle point type if this helps .