Sizing Die Alignment...

E

eww1350

Guest
While neck sizing some 30BR cases with my Redding type "S" neck die, I noticed that the witness mark was heavier on one side than the other (partial neck is sized only 60% of the neck length)...I tried rotating the case and running it thru the sizer again...it sometimes made the witness mark more even, but I was concerned that I had cases with crooked heads...I started investigating a possible alignment problem with the press, die, and shell holder...what I found was that the locking ring threads were loosely fitted to the die body...after scrounging thru some spare die parts I found a locking ring that fit very nicely, and the sizing mark was simmetrical around the case neck...
I began looking at the decapping rod alignment at the bottom of the die, and it also was not centered..again I had to flip the loose fitting locking ring of the decapping stem and hold in a centered position while I tightened it..
Needles to say I was not impressed with how sloppy the thread fit was on the components..which led to some run-out issues on my loaded rounds...
I also check several different shell holders that gave slightly eccentric sizing mark...
 
I presume that you don't have any obvious problems with any other dies in the press you're using so that would seem to eliminate the press. It's possible for anyone to turn out a lemon I suppose, but Redding's dies are covered by a lifetime warranty I believe. Send them an e-mail <www.redding-reloading.com>, or give them a call (607) 753-3331 and tell them what's happening. They're knowledgeable and I think really want people to obtain the best results with their products.

I'm also assuming that you're using turned Lapua brass, or brass that has uniform neck thickness. Necking up cases can lead to uneven necks which could cause what you're experiencing I suppose.

Good luck
 
I have always wanted to do a lock ring squareness test,but lacking a lathe, I will leave it to one of you. It would seem to me that if one cut a section of 7/8-14 thread on one end of a bar that had been chucked in a three jaw, (and left it in place for the full test), that one could screw on a series of lock rings, lock them and then indicate their faces for runout. One could evaluate one type and/or brand VS another and check for repeatability by doing multiple tests on each ring. A truing cut could also be taken. What do you think?
 
The simple and maybe too easy method is to install a 7/8" ID "O" ring under the lock ring. Squaring the bottoms of the lock rings, with the tolerances involved in the threads of the dies and lock rings, would seem to me to make a lot of work for questionable improvement. When the lock ring is moved will the squaring cut still be perpendicular with the centerline of the die?
 
Hi

I dont lock it at all I let it flop around in the thread & let the case align itself.Also the split nut will not stay flat but follow the threads contour.
I don't check run out till i have a problem so i havn't done it at all.I'm going to after next shoot but if i dont know it wont bother me till then.
Good shooting Jim
:eek:
 
I put my 6ppc die in the press and it too showed a small amount of miss-alignment..(the sizer button mark was slightly heavier on one side).I am using a 10x jewelers loop...
So I decided to chuck the die up in the lathe and on the threads and took a light cut on the locking ring...
It seemed to help...
I am using the RCBS Partner press..(I have 2)..
The proof is in the runout of the loaded round..It was really good..Less than .001"
 
Dies and Lock Rings

I gave up on the conventional press, hold the die in place with heavy ram pressure and lock it down thing about 1978, mostly because it took too long to change dies. I purchased a Bonanza CO-AX press and have never looked back, I still use that same press today. I think that Forester owns the design now, I purchase Forester lock rings (really you have to) for all the new screw in dies when I purchase them. I use the other ones for adjustment locks on table leveling legs and they work GREAT! All the frivolity aside there are literally tons of bullets made with screw in dies, and they shoot pretty good! Take a look at that press or your set up procedure.

Play Straight, (no run out)
Nic.
 
I removed the spring clip that holds the shell holder in. Made a sleeve that
retains the shell holder and allows it to float about .005 in all directions.
Most die parts can be improved by facing while in position, it it must
be tested first. straight bushings are very rare, so buy a couple and check them
 
Speaking of striaght bushings...a friend who has a lathe, and who was impatient to shoot a new rifle, made his own bushing, with a drill and boring bar, in a single setup. After cutting it off, he beveled the hole to get rid of the slight burr. I have been toying with having him make me one. Made that way, I ga run tee that it will be straight, and concentric. Have you measured your bushings in several places with a neck mic.? It's no wonder the dies are designed to let them float. The other test that I would like to do on a lathe is to see how much they wobble when jamed on a tapered mandrel that is running true.
 
Floating dies ...

Don't laugh John Whidden markets shell plates for a Dillon progressive presses that allow the dies to float. I use to load on a single stage press. I now load on a Dillon progressive press but load single rounds at a time much like a turrent press. There is enough slop to allow the case and die to line up.

Rustystud
 
at the end of the sizing stroke, the bushing stops at the face on the bottom
of the decapping pin holder. That must be square, to the centerline axis of the die. The ends of the bushing must be square with the bore in the bushing.
If the bushing you use has numbers stamped on them, the numbers will be raised and thats good for .001 or even .002. out of square. When facing
parts with internal threads, do not screw them up to a shoulder, you will
be misled by the opposite side. I make some bushings and after facing
and boring them and the initial polish, the must be cut off and undercut
without ever removing them. If not they will have ends that are not parralell,
or perpindicular to the bore.
 
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