Concentricity - setting up dies - runout

[jimbires]

Tried the "O" ring trick today on the Turret Press. I dont have the guage yet to measure but getting the expander in was easier and also easier on the seating die without hitting. I also used a smal "O" ring on the die inserts. It worked better. For me a worthwhile trick if just for better alignment.

Thanks all,

dig , you probably already know this , but I thought it's worth mentioning . be sure to clean / brush the case necks and also lube them inside before using a resizing die with the neck expander ball . if you hear a dry squeak when pulling the expander through you are most likely causing run out . I use a case neck dipper like this , when using that type of die . Case Neck Dipper Mica by Lyman - Case Preparation - Reloading - by Lyman - Case Neck Dipper Mica by

 

[Bart B]

I disagree with your accessment of the effect on OAL of an O ring under a die vs. simply screwed down tho.

I'm not referring to tha OAL, or bullet tip to case head measurement which Over All Length is. I'm talking about case headspace that's measured from the case head to the datum line on the shoulder. The length of a fired case increases whether neck only or full length sized.

 

[boomtube]

Thing is, the case shoulder will hit and stop at any point we set the die whether there is an O ring squeezed under the lock ring or not. The die certainly isn't going to move down and it can't possibly move up past solid contact with the press threads! A compressed O ring can achieve that solid contact as well as a bare die.

Not that it matters much but, as an issue of reloading's correct technical semantics, OAL is not releated to cases, as such; case length is case length and that IS head to mouth.

OAL (or COAL) correctly refers to cartridge "Over All Length", which automatically includes the seated bullet. Adding a "C" for "Cartridge" as some do is superfluous but acceptable terminology.

 

[Bart B]

Not that it matters much but, as an issue of reloading's correct technical semantics, OAL is not releated to cases, as such; case length is case length and that IS head to mouth.

OAL (or COAL) correctly refers to cartridge "Over All Length", which automatically includes the seated bullet. Adding a "C" for "Cartridge" as some do is superfluous but acceptable terminology.

Well, OK. I blew that in my earlier post, so I edited it to be correct. Thanks for pointing this out.

I know what you mean by an O-ring not effecting die position, but I did get a greater spread in case headspace with one under the die's lock ring. Not much, maybe 4 to 6 ten thousandths greater was all.

 

[boomtube]

"...but I did get a greater spread in case headspace with one under the die's lock ring. Not much, maybe 4 to 6 ten thousandths greater was all. "

Don't doubt that at all. Do wonder if something else was in play, more than just the O ring tho. ??

 

[Bart B]

"...but I did get a greater spread in case headspace with one under the die's lock ring. Not much, maybe 4 to 6 ten thousandths greater was all. " Don't doubt that at all. Do wonder if something else was in play, more than just the O ring tho. ??

I do know for a fact that the lubricity of the case in a full length sizing die will effect the case headspace after sizing it. More and slipperier lube means it'll be shorter; less and more sticky and it'll be longer. Every press known to man has some spring in it, but my Rockchuckers are at the lower end.

I used to get a 1 to 2 thousandths (sometimes more) when rolling clean cases on a pad coated with traditional lube. After switching to a 60%-40% mix of STP and Hoppe's No. 9 with fifteen drops of it dribbled on a foam liner in a coffee can tumbled by a Thumblers Tumbler half full of cases for 15 minutes, they were unifomly lubed to keep sized case headspace spread to under a thousandth.

 

[sp6x6]

I have noticed same , and speed of reloading stroke. Now I measure every step, and my shoulder , headspace varies if I size twice, sometimes, and varies if I use 3 different bushings to read. From shoulder to neck area, When the load is chambered, my rifle seems picky at the closer to neck area, than down by shoullder

 

[boomtube]

"the lubricity of the case ... More and slipperier lube means it'll be shorter; less and more sticky and it'll be longer."

Interesting and surprising fact isn't it? One reason I've gone to Imperial and Unique lubes is that I can actually control how much is on my cases with finger tip application quite well and I never could be consistant when using a lube pad. Another factor is work hardened cases; new (or recently annealed) cases won't springback as much as those that have been fired several times.


"Every press known to man has some spring in it, but my Rockchuckers are at the lower end."

Another interesting fact that's often misunderstood. And the press linkages also have some varing amounts of slack and the oil in the pins also seems to matter, especially if we operate the lever at variable speeds.

As an amateur home shop mechanist I have the right tools to properly measure press spring. Many years back I bought two little Lee RELOADER presses for de- and re-priming and was curious about their spring. Used the same box of fired .30-06 cases and same die/shell holder adjusted to FL size 4-5 cases to the same point in both of the tiny alum alloy C presses and then in my RC II. Surprised me that the RC lifted more than 2.5 thou at the top of the sizing stroke but there wasn't enough spring in either of the Lee's to measure, it was well under a thou! Point being that alum alloy is actually more rigid within it's tensile strength limits than cast iron but that is NOT the way Lee's light alloy presses are presumed to be! (I've gotten some howls of outrage from people who insist their cast iron RC is totally rigid and that Lee's presses are 'soft and flexible" - not so! )


6X6 is correct that the rhythm of press operation can matter, at least as much as a couple of thou at the shoulders or in OAL. Only after I got my first RCBS Precision Case Mic and could actually measure the effects of varying lever technique did I imagine it would be so easily changable. Slowing down and pacing myself obtains much more consistant results than my previous rather inconsistant lever practices. Not that I've ever seen any differences in acccuracy from such tiny variations.

 

[Bart B]

Another factor is work hardened cases; new (or recently annealed) cases won't spring back as much as those that have been fired several times.

I think this depends on how much the brass case gets sized. I've reloaded a new Federal .308 Win. brass case 47 times, fired with max loads and full length sized each time. Neck tension remained uniform enough to keep bullet seating force quite consistant and muzzle velocity spread from first to last firing was no more than 30 fps. Standard SAAMI spec chamber was used as well as a standard RCBS full length sizing die but the die's neck was lapped out to 2.5 thousandths smaller than a loaded round's neck diameter. Case was never annealed in this process.

 

[dig]

Thanks for all the replies this is turning into a huge thread. I have gleaned a lot of information. To reply to a few things.

1. I full length size with expander ball
2. I use Imperial sizing wax with a tiny squirt of rooster lube in the case mouth, have use Imperial dry lube dip in the past as well, no dragging, no stuck dies
3. I have use multiple strokes to seat for a while seems to help
4. I loosened my dies and used the "o" ring trick is really has helped on 300 Wby and 243 WSSMthe calibers I have tried so far, if just for alignment of the expander (redding dies)
5. Canceled the order for the Hornady Gage will be ordering another type more touted type

Also since I started using stainless tumbleing media and depriming prior to tumbleing I have not brushed a case neck. If you have not tried this formatt do so, save a lot of time dealing with primer pockets and case necks.

 

[Trickymissfit]

I do know for a fact that the lubricity of the case in a full length sizing die will effect the case headspace after sizing it. More and slipperier lube means it'll be shorter; less and more sticky and it'll be longer. Every press known to man has some spring in it, but my Rockchuckers are at the lower end.

I used to get a 1 to 2 thousandths (sometimes more) when rolling clean cases on a pad coated with traditional lube. After switching to a 60%-40% mix of STP and Hoppe's No. 9 with fifteen drops of it dribbled on a foam liner in a coffee can tumbled by a Thumblers Tumbler half full of cases for 15 minutes, they were unifomly lubed to keep sized case headspace spread to under a thousandth.

I have not tried it yet, but have been told to try Royal Purple and some stuff Lucas Oil sells. I have a bottle of Royal Purple, but just have not tried it yet
gary

 

[boomtube]

"I think (hardened brass) depends on how much the brass case gets sized."

Exactly so. What that means of course is how much the brass gets cold worked each cycle. If we have a tight chamber and a loose sizer we have the best possible situaltion with common tools. The opposit situation will work a lot more and hardening will increase. When brass is hard it springs back more, both after firing (shrinks back more) and after resizing (re-expands more). All meaning that if we REALLY want to resize precisely we have to keep our cases segrated AND expect to make minute adjustments as we go. I get amused by posters who claim they adjusted their dies perfectly once and have never changed them; ah well, it's harmless foolishness!

(But don't let the gubbermint know you're 'segregating' anything, they would put you in jail before even trying to understand what the smell you're really doing! )


Dig, you did stir up some good conversation, hope it has helped ground you a little better, not much of this will be found in a reloading manual. I'd suggest you look at the Sinclair concentricity gage. And get the lower cost dial indicator, it will do all any reloader needs done and do it well.

 

[dig]

Thanks boomtube, this has been a great thread and I have learned a lot. I just ordered the H&H Gage after much research Concentricity Gauge. The fact that it will eliminate case problems to a larger extent intrigued me. I think the biggest lesson I learned is I am certainly not as ANAL as many who commented on this post, I am trying to explain that to my girl friend (she is not buying it though).

A bit off topic but motor oil for sizing? Scares the heck out of me to contaminate a primer or go through another major step in the process (yes I know you can soak, tumble, whatever).

Thanks everyone and keep the fight going!

 

[boomtube]

"...motor oil for sizing?"

I've been reloading for well over four decades. I've used most commercial case lubes and find that most are sufficent. I've experimented with a lot of alternates; some work well, some work moderately well, some are prone to letting cases stick.

Given that a good lube will prevent stuck cases, be easy to apply AND remove, be harmless to powder and primers and be low cost, there are several that work very well; motor oils are not among them. Even the most pricey case lubes are cheep in the quanities we use so attemps to 'save money' with them seems pointless. Well, except the expensive spray-on types, which I find pointless anyway.

IMHO, the best of case lubes are soaps like the RCBS/Lee water solubles, or soft waxes like Imperial/Unique and equivilent alternates such as Kiwi Mink Oil and Sno-Proof boot treatments. Not only are they all great sizing lubes but they are harmless and easy to remove from both cases and fingers...and are plenty cheap enough.