Help W/ reloading runout problem....

[hemiallen]

Starting to reload for my 300 wby. Borrowed an early 60's set of RCBS dies, sorted some once fired Wby brass form my gun, and some new Nosler brass. Used my sinclair dial indicator to get 5 each brass w/ .002 or less neck runout, neck walls within .001 so that is half the runout.

Take a bad brass to test the dies, had .003 runout. Run die down to shellholder, Rockchucker press) and lubed neck outside w/ h20 soluble rcbs lube, white graphite neck inside. Mark belt for rotation. FLS and measured increase in runout to .004. Resize at 90 degree's and runout .011....NOT GOOD

Loosen stem for floating, and improved, but had to keep rotating brass to get back to .003 neck runout.

FL sized a spent Ctg, WBY brass. Same setup, went from .001 runout to .010.... rotate until I got back to .002 runout, loose die and stem.

What is going on? The base at the belt on the FL sized once fired brass is .0005 smaller than before FL sizing, norma new is .002 under both. Looks like neck size die may be in order? I will use new brass for hunting.

Thanks for any help

Allen

 

[Winchester69]

Sounds like the sizing stem needs straightening. Or just use it set loosely. You can check it on your run-out gauge.
.

 

[rrwildlife]

May be a dumb question but have you cleaned the die? I had a Hornady die that got some buildup of lube and crud and concentricity went through the roof.

Regards,

Ryan

 

[Preacher]

I use a O ring under the lock nut with just a bit of pressure on the nut, and it seems to help keep it centered usually..

 

[hemiallen]

Thanks for the replies.

Yes, I did clean the die internally, and it was oily/ goopy. Interesting idea on the oring.

I found a way to keep the brass within .002" runout. I marked the belt w/ a felt tip pen, lube the case sparingly and run it in w/ the die set 1/ 16th shy of contacting the shellholder using a shim washer. Then I lower the die after the primer is punched out, rotate it 180 degree's and resize it. The only issue is this basically sizes the neck and not much of the body is sized, bujt they fit loosly in the chamber, ie no felt resistance from a tight fit of the brass.

Thanks

Allen

 

[memilanuk]

Something you might consider... I know a lot of folks have romantic notions about how things were made better in the 'old days'... but in my limited experience, reloading dies ain't one of them. Shooters have gotten a whole lot more discriminating, aka picky,how many shooters back in the 60's even knew what loaded round runout was?) and the products have, generally speaking, gotten better. Especially w/ automation and CNC machining.

Might be time to just pony up for a newer,and better) set of dies.

YMMV,

Monte

 

[BoydAllen]

Do you have any way to measure shoulder bump? There is no head to shoulder SAAMI spec. for belted cases, with the result that setting most belted case FL dies so that they touch the shell holder results in excessive shoulder bump. Beyond the obvious problems that this causes with case life, due to repeated stretching just above the web, pushing the shoulder back an excessive amount can also be bad for neck runout. Also, if you don't want to replace your die with a bushing type FL die, try using a liquid lube that is water soluble inside the necks and go very slow when expanding on the down stroke., Of course you will have to clean and dry the inside of the cases after sizing.)If you pull out your expander assembly and size a fired case, and compare its runout with the others,,without bumping the shoulder back excessively)you should start to see the source of your problem. A bushing die will allow you to pick a bushing sized so that the expander barely does any work. It is the pull on the neck during expanding that cocks them. The shoulder gives unevenly under the stress. Using a slick lube and slowing way down helps reduce the peak value of this axial stress on the case. For a hunting caliber a shoulder bump of .001- .002 as compared to a tight case should be OK. Just remember that once fired brass, or brass that has been fired after excessive sizing will not be fully expanded to the shoulder. One thing that I found interesting about a .300 Weatherby that I was doing a pressure test on at the range was that I could neck size the case several times without getting a tight bolt. This was with a neck die.

 

[hemiallen]

Thanks Monte. Probably a good investment.

Mr Allen, thank you for the suggestion. I do see the benefit of not FL sizing, and have a 1/16" thk precision washer to back the FL set die off the shellholder and become a neck only die, but realize the sacrafice of minimal alignment doing this. I too see I could get away neck sizing at least 1 or more firings. The hot load I fired in the backyard didn't oversize the web above the base more than factory Wby ammo, and fits well in the chamber.

I agree on the stem/ ball issue, now recalling why I ordered the floating ball stem dies when I shot IHMSA, I believe redding, for my 7mm Int-R TC barrel.

Thanks for the information. To the range tomorrow with .002-.003 runout ammo.

Allen

 

[Ol_FlatTop]

Mr. Allen,

Your said:
"A bushing die will allow you to pick a bushing sized so that the expander barely does any work."

I thought a bushing type sizing die has no expander ball. Am I wrong,once again), or am I misreading your post?

Dan

 

[treeman]

ol flat top, you can use a bushing die with or without an expander ball. if your necks are uniform thickness or real close you wont need an expander but if tolerance on necks is not so close then an expander helps even out neck tension. regards,treeman

 

[rayjay]

Why worry about it ? With your rifle and cartridge I doubt a target would show the difference between perfectly concentric ammo and ammo with .005 runout.

 

[hemiallen]

Interesting on the no expander, didn't consider that. My necks are .0015 max variation, but I could borrow a neck turner to make that more uniform.

I have read many times .005 runout is fine for a hunting rig, .002 is needing improvement on a bench gun. Why not make every round as perfect as possible? I have found lee makes a collet neck die, and if my local shops had one I would own it by now.

Thanks again
Allen

 

[BoydAllen]

The Redding S type dies have both a decapping pin retainer, that is designed to not touch the inside of the neck, and an expander, that is. You have that choice. The competition neck dies only have the decapping pin retainer. If you are not turning, not using an expander ball results in the irregularities of neck thickness showing up as differences in neck tension and ID roundness. By selecting a bushing that causes an expander to just barely do any work, cases are not distorted, and the necks are more uniform as to tension, and ID roundness. It is only when there is a strong pull on the expander, due to excessive neck sizing that necks are cocked, relative to the case body.

 

[Ol_FlatTop]

BoydAllen:

Thank you for reminding me about equipment I forgot I had! I have Redding Type S dies, and a quick check of the green box shows an expander button that I decided not to use when I first bought it. Couldn't figure out why anyone would use it, but now I understand. I'm using Lapua 20 TAC brass. Since I don't have a tool to measure neck concentricity, I tried outside neck turning on several cases and found there were no high spots, so I don't turn these cases. I'm using a 0.229" sizing bushing. The neck on a loaded round measures 0.2305" OD. I probably won't need the expander, right?

In the spirit of rayjay's postscript, I shall question a response:
If a case neck is thicker on one side than the other, whenever the diameter is changed,smaller by a neck bushing, or bigger by an expander ball) isn't the thinner side getting worked more than the thicker side? Especially, since the case body is free to move laterally when the ball is drawn though the neck? Is it possible for the bushing or the expander to flow the brass sideways, from the thick side to the thin side?

Rayjay:
HemiAllen:

I'll also question rayjay's response!
I'm not "worried" about the minute details of my reloading! It's my hobby; it's fun to consider all the details and make the best possible ammunition I can. And there are always more interesting things to learn from other "projectile enthusiasts"! Who knows what 2 little details might combine for a better group? Any improvement I do find at the shooting bench makes me more confident when I go hunting.

 

[DrJeckyl]

I had the same issues when I went to bump the shoulder back on my 260 cases before I received my custom dies. I had less than .001 runout on fired cases using the same sinclair gauge you have.

After F/L sizing and a .002 shoulder bump, I had .003-.004 runout at the neck, hit the neck die and some cleaned up to about .002-.003 runout.

The thing is, the neck is thrown way out when the steel rollers hit an irregular portion of the body when rotating. The neck may be round but after run through the die, any thick portions of brass won't stay uniform after running through the sizing die...the brass isn't perfect, but a fired round is pretty straight.