Concentricity Issue

[Jayhawker]

A standard dial indicator in a fixture. The set-up was bought as a unit from Sinclair.

At this point, FWIW, after endless testing, I have settled on decapping with one fixture, sizing with the Forster die minus the expander and expanding with a .042" expander/mandrel. It gives me about .003" neck tension. I'd rather have .002' but until I can figure something else out, it will have to do.

I don't doubt that the issue comes from the expanders in both dies or something in the way I've got them set-up since without them the dies are producing close to .000" runout. After using the expander/mandrel set-up, I'm getting .001" or less. I use Forster dies for my 6X47 however, with perfect results.

 

[chkunz]

A standard dial indicator in a fixture. The set-up was bought as a unit from Sinclair.

At this point, FWIW, after endless testing, I have settled on decapping with one fixture, sizing with the Forster die minus the expander and expanding with a .042" expander/mandrel. It gives me about .003" neck tension. I'd rather have .002' but until I can figure something else out, it will have to do.

I don't doubt that the issue comes from the expanders in both dies or something in the way I've got them set-up since without them the dies are producing close to .000" runout. After using the expander/mandrel set-up, I'm getting .001" or less. I use Forster dies for my 6X47 however, with perfect results.

We live in a world of tolerances. Reducing tolerances cost money. Our reloading dies and presses are a compromise between tolerances and cost like many other things. You will get a variation in results even when you use the same model from the same manufacturer due to the variation in dimensions from item to item. The best we can do is use good methods (expander mandrel vs expander ball for example) and measure the results until we find what is acceptable. Knowing what is acceptable is another issue, most folks that worry over run out do not know what it worth on the target if anything.

 

[snert]

A standard dial indicator in a fixture. The set-up was bought as a unit from Sinclair.

At this point, FWIW, after endless testing, I have settled on decapping with one fixture, sizing with the Forster die minus the expander and expanding with a .042" expander/mandrel. It gives me about .003" neck tension. I'd rather have .002' but until I can figure something else out, it will have to do.

I don't doubt that the issue comes from the expanders in both dies or something in the way I've got them set-up since without them the dies are producing close to .000" runout. After using the expander/mandrel set-up, I'm getting .001" or less. I use Forster dies for my 6X47 however, with perfect results.

We live in a world of tolerances. Reducing tolerances cost money. Our reloading dies and presses are a compromise between tolerances and cost like many other things. You will get a variation in results even when you use the same model from the same manufacturer due to the variation in dimensions from item to item. The best we can do is use good methods (expander mandrel vs expander ball for example) and measure the results until we find what is acceptable. Knowing what is acceptable is another issue, most folks that worry over run out do not know what it worth on the target if anything.

Agreed TREX. While I too will take straight ammo to 'crooked" ammo, there comes a point where I KNOW I (and most everyone else here) cause more than .002 concentricity concerns when we pull the TRIGGER. now if half your sport is making ammo that is straight, then more power to ya. But if it is shooting, and you are not Super Shoot BR, then that gauge is more likely to give you unneeded ulcers than anything.

Just my 2 cents

Snert

 

[Jayhawker]

My philosophy on most of this is that I will do as much as I can to increase the possibility of increased accuracy-only up to a point. When it gets to the point where something I enjoy becomes a PITA, I stop and settle for what I've got. That's where I'm at with this. I will use the mandrel/expander for now and not worry about an extra .001" neck tension. I may go back one of these days and fool around with the way I've got the expanders set-up or I may just have made a .043" expander-cross that bridge when I get to it. Id rather go shooting. One thing I've learned from this hobby. There's is no end of money and effort trying to get a few thousandths inch. I watched a friend literally wear out a barrel just looking for the perfect load. That's just crap.

On an ideal day i.e. no wind or mirage, this 6 BR will shoot consistently in the .2s and .3s MOA at 300 meters. No prize winner but the only person I compete with is myself.

 

[barefooter56]

jayhawker,
There is lots of good information here. But first of all "never check the concentricity of a NEW cartridge case .( Which you probably know.) The chamber of your rifle is the last forming die that cartridge case goes through when its fired. Unless you are using your Forster die in a FORSTER CO-AX press that is designed to allow the die to "float" and self center its self the issue may be the lock ring. Standard loading presses use the 7/8ths-14 threading. There is lots of clearance between the threads of the die and the threads of the press that can cause the die to "cock" in the threads even if you are using a cross-bolt lock ring.
The o-ring under the lock ring fix would help here. But first loosen the lock ring and thread it up the die a wee bit while holding the die in place and run a piece of your .005 run-out brass through it and check it again. (With a standard lock ring just back the grub screw out away from the threads and do this test). This will allow the die to float and center itself in the threads. Same methods can be applied to the decapping assembly by an o-ring under its locking ring. With the tolerance stacking that takes place because of thread clearances it sometimes is beneficial NOT to have everything locked down tight. L.E Wilson dies don't have threads so this issue is taken out of the loop entirely. General rule I was taught was .000-.005 runout is the acceptable tolerance spread. I use this and have seen that it does work even with my Palma ammunition. But what it comes down to is what YOU are comfortable with.

 

[Jayhawker]

Phil:

This is a Forster press with Forster dies and lock rings. The die floats in it's retainer slot in the press. As mentioned previously in other posts, I have taken the decapping assembly out and used an expander to get good results. I am assuming that the expander assembly or the way I have it set-up in the die is the problem. This holds true for a Redding FL die as well. In both cases, when the brass comes out of the dies without the decapper, it's as close to .000" as it could be. I then use an expander and get no more than .0015" run out which is fine with me. However, it is producing .003" neck tension which is a bit more than what I understand to be desirable. As soon as I have some more fired brass, I will experiment with the decapper assemblies. The Forster decapper sits on a rubber washer. The Redding has nothing. Could be I have them too tight regardless of what they're mounted on

 

['Freak]

Additional to going the extra efforts to center and square the de-cap/expander stem within the die body, I’ve swapped in Redding’s floating carbide expander button kits.

 

[Jayhawker]

OleFreak:

Judging from the picture on their site, Redding is trying to catch-up with Forster with the new expanders.

 

[blastit37]

Make sure your expander button is as high in the die as possible. The die should start expanding the case just as soon as the button leaves the neck.

 

[Jayhawker]

blastit37:

I've seen that suggested before. I may have to try that however, Forster is very specific in their instructions that come with the die exactly where the expander is to be located not that I couldn't change that.

 

[blastit37]

I have found that if there is some wobble in the stem of expander, shortening the expander reduces the wobble. You can tell when you are too short when you hit extra resistance. Back off that resistance or you will crush the case. A smooth push with no change in resistance is good. Easy to try.

 

[CatShooter]

OleFreak:

Judging from the picture on their site, Redding is trying to catch-up with Forster with the new expanders.

Really... where. What page or URL?

I can't find it and I would love for them to change.

 

[Jayhawker]

This should get you there:

http://www.redding-reloading.com/online-catalog/28-carbide-size-button-kits

 

[CatShooter]

This should get you there:

http://www.redding-reloading.com/online-catalog/28-carbide-size-button-kits

That is NOT a high expander - it is "The same ol' same ol' "...

This is a "high expander"...

 

['Freak]

Haven’t checked on Redding’s site lately. I’d love to see ‘em all offering floating steel and/or carbide expander buttons in .0005” increments to both sides of what’s ‘standard’; and with the button mounted high enough on the stem that along with it being adjustable, we could tweak ‘em so that the expander begins acting on the neck before the neck has been pulled totally free of the neck size portion of the die.

 

[BoydAllen]

Whidden die parts interchange with Redding, and they offer expanders in various sizes. You might want to give them a call. The high expander does work better, and polishing the expander helps, along with putting an O ring under the stem nut on RCBS dies. Lubrication of the inside of necks, and press operating technique are involved as well. If you are dealing with a RCBS one piece die, you can decap first and then adjust the expander stem so that the expander is in the high position. What that does is start to expand the bottom of the neck while the top is still in that part of the die, but don't raise it too far, it will put you into a bind. Substituting the use of an expander die and mandrel as the last step in the process, after sizing with no expander in the die, has given the best results of all...when I have been stuck working with a factory one piece die, and factory chamber.

 

[Jayhawker]

You're correct, Catshooter. I was just looking at the shape of the expander-not where it was located. Sorry.

 

['Freak]

Whidden die parts interchange with Redding, and they offer expanders in various sizes. You might want to give them a call. The high expander does work better, and polishing the expander helps, along with putting an O ring under the stem nut on RCBS dies. Lubrication of the inside of necks, and press operating technique are involved as well. If you are dealing with a RCBS one piece die, you can decap first and then adjust the expander stem so that the expander is in the high position. What that does is start to expand the bottom of the neck while the top is still in that part of the die, but don't raise it too far, it will put you into a bind. Substituting the use of an expander die and mandrel as the last step in the process, after sizing with no expander in the die, has given the best results of all...when I have been stuck working with a factory one piece die, and factory chamber.

I’d thought that a possibility but didn’t know it was fact that Whidden guts will swap into a Redding.

Will they (Whidden) also increase the ID of and polish the neck size area of my one piece Redding full length dies? I don’t recall seeing on their site where they offer to service other manufacturer’s dies, might’ve missed it.

 

[bigedp51]

That is NOT a high expander - it is "The same ol' same ol' "...

This is a "high expander"...

CatShooter you should clarify that Forster's "High Expander" dies are made in Illinois and not in Colorado.
Meaning the dies are not a total Rocky Mountain High. :

John Denver-"Rocky Mountain High"
https://www.youtube.com/watch?v=LLWD2WIvRQk

CatShooter, I had arthroscopic knee surgery today so I'm sitting in my Lazy Boy recliner with my lap top super glued to my calfs and ready to pounce on unsuspecting posters. I'm also using two of my modified Enfield rifles as crutches because they are such useful firearms and fit in anywhere. Bazinga. ;D

 

[barefooter56]

Jayhawker,
Good set up. Are you using expander mandrels that are normally used with neck turning tools? If so that is one way to help your concentricity and neck tension. (which you obviously already know). You can have these mandrels turned or polished down to really get a custom result if you need it. Other way is to contact Forster and have them polish the neck sizing portion of the die out to give you the neck tension you need. On Redding dies ( either standard or Type S) I went to their carbide expander ball. Also on the Type S dies I found that I got a better result using the L.E. Wilson bushings in the die. These are "funneled" and not a "tubular" style bushing like the Redding bushings are.