Full Length Sizing

[roc1]

Question on full length sizing if you set die to push shoulder back by backing it off shellholder. I see shoulder length increase a few thousands so by what I have learned you actually move shoulder forward with die first then by where you set it then it will push shoulder back. I was trying to use compartor setup on match die so I guess setting die back in by setup instructions to touch shellholder will probably be a lot closer to being right than backing it out which increased length by .003-.004. I didn't relize dies actually moved it up and back until it hits shoulder of die which then pushes case shoulder back. Just trying to understand all never really tried to bump shoulder before always just set by die instructions on neck or full length either one. Like to try bushing die and get better loads just wanting to learn better ways.
Thanks
roc1

 

[Bart B.]

Roc1, you're one of the not too many who've learned that bottleneck case shoulders get pushed forward on the case while the full length sizng die squeezes their body down. That happens until the case is far enough into the die's chamber to stop against the die's shoulder, then the shoulder gets set back some amount until the case stops going up into the die. If the die's set to not size all of the case neck, then that case shoulder will be further forward that when it was after it was fired and before it was sized. That leads to the bolt binding a bit when chambering a round and it's detrimental to best accuracy.

Where that shoulder gets positioned relative to the case head varies. If the shellholder doesn't stop against the bottom of the full length sizing die, the small amount of press spring will vary depending on how slippery the case is in the die. So, the case shoulder position relative to its case head will vary a few thousandths.

If Redding's competition shell holders are used and the one of the correct height above the standard .125" is in the ram, then the die adjusted to let the shell holder touch it at the top of its sizing stroke, that variable will be redeced from a few thouisandths to a few ten-thousandths inch. That lets bullets seated to some uniform position have the same distance they jump to the rifling for several shots.

Ideally, a gauge can be used to measure case headspace on fired cases then again after they've been full length sized. If the case shoulder is set back 1 or 2 thousandths from its fired position all's well for bolt guns. Semiautos need fired case shoulders set back 3 to 4 thousandths. The RCBS Presision Mic or Hornady LNL gauges are excellent. You can also do what I've explained in post #35 in:

http://thefiringline.com/forums/showthread.php?t=544432

 

[roc1]

Thanks Bart so if I reset die to touch existing Shellholder and that is not enough then you need competition shell holders to move shoulder back enough correct?
Are bushing dies better even if you don't turn necks for standard loads not competition guns?
Thanks again
Roc1

 

[Bart B.]

Typically, the die needs to be a few thousandths above a standard shellholder when full length sizing cases when the press ram stops at its maximum height. The further the die is from the bottom of the shellholder where the case head rests, the less the case shoulder will be set back.

When the shellholder touches the die's bottom, the case shoulder is usually set back to industry minimum. As most rifle chamber's headspace is greater than that, such a die setting sizes the case too much. That leads to short case life and the case head starts to crack off the body due to too much working of the brass.

Competition shell holders (by Redding) come in five .002" incremental heights above the standard .125" shell holder height measured from its base where the case head rests and the flat part on its top that stops it from going too far into the die.

For example, a standard .125" high shellholder stopping against the press sizes the fired case setting its shoulder back several thousandths to 2.000" from the case head. A Redding competition shellholder with a .129" height pushes the fired case .004" less up into the die; the case shoulder is now 2.004" from the case head. These shellholders allow one to be used that sets the fired case shoulder back a couple thousandths; whichever one is right for the cases coming out of your rifle. Another rifle using the same cartridge may well need a different height shellholder as it's chamber is a different length.

Full length sizing dies with bushings the correct diameter (typically .002" less than a loaded round's neck diameter) produce match winning and record setting results. As long as there's no expander ball to bend the sized down case neck after it comes out of its sizing chamber. Deprime and clean cases before using bushing dies without the decapping pin and expander ball; they're not needed with bushing dies. The only dies better are the one piece ones with their necks honed out a bit; Forster hones out their dies for an extra $12 each. If you want two different sizing die neck diameters, you'll need two of those dies, so bushing dies from RCBS or Redding are the best choice.

 

[F. Guffey]

It is assumed by all reloaders the die contacts the shell holder, there are times the die does not make it to the shell holder, there are times the case has more resistance to sizing than the press has ability to overcome.

I measure the length of the chamber from the datum to the bolt face first. Competition shell holders from Redding are nice, not necessary but nice. Before the competition shell holders I used feeler gages, after the competition feeler gage? I still use feeler gages. I know, most will not make the effort.

F. Guffey

 

[Bart B.]

It is assumed by all reloaders the die contacts the shell holder..

???

 

[roc1]

Do Redding bushing dies work ok on unturned case necks? How do they compare to Lee Collet dies? I know they are neck only but to they work as well as bushing dies?
Thanks
Roc1

 

[Bart B.]

Oops; forgot to comment on turned necks.......

All bushing dies work well on unturned necks. If the case neck wall's got a .002" spread in thickness, a bushing die will size it such that the case mouth center is only .001" off center. That equates to a bushing die sizing turned necks with zero spread in thickness yet having .001" in bullet tip runout. Bullets straighten up quite well entering the rifling as long as their runout or off center position in the chamber throat is no more than 1% of the bullet diameter. For 30 caliber bullets, that's .003", which is easy to do with modern reloading dies.

Full length sizing dies keep the case body, shoulder and neck aligned on the same axis. Neck only sizing dies don't to that; they hold nothing in line with the die's neck except the case neck. Lee's collet die holds the case neck against the sizing stem but its shoulder and body are not aligned with the sizing stem axis. This is why benchresters finally switched a few years ago to full length bushing or standard dies whose neck diameters are 1 or 2 thousandths smaller than a loaded round. The parts of such sized cases are more in line with each other. Other competition disciplines have been full length sizing their fired cases for decades in standard full length sizing dies with their necks honed out so an exapnder ball doesn't need to be used.

Fired cases that headspace on their shoulders sized down 1 or 2 thousandths will always fit the chamber to align the bullet best with the bore. Their shoulders perfectly center in the chamber shoulder from firing pin impact and that centers the case neck and bullet there, too. Neck only sized cases don't do that all the time; their necks are often not centered on their shoulders. Case necks float free in chamber necks; there's a thousandth or more clearance around them.

Sierra Bullets uses Redding full length sizing dies on all their rifle cases testing bullets for accuracy; bushing dies for cartridges they're made for. They do not prep their cases in any way; never have. They get 1/4 MOA accuracy with their best match bullets in their indoor 200 yard range. I've seen some of their 30 caliber 10-shot test targets that were down in the 1/8 MOA range; group after group after group. Shot with ammo having a maximum .003" bullet runout/offcenter issue in the chamber.

Note that good factory match ammo that shoots 1/3 MOA at short range was made with unprepped cases in dies without expander balls.

 

[Griff SASS93]

It is assumed by all reloaders the die contacts the shell holder..

???

Quite wrongly it may be assumed. Reading any good reloading manual will provide the instructions on properly setting all the dies necessary. Every instruction I've read states that dies should be set to NOT touch the shell holder. None of my sizing dies touch the shell holder... The closest one is my 45ACP set... they're from around 1973... and have loaded tens of thousands of rounds, and are still allowing any 45ACP case sized in them to chamber in any of my 6 1911s. Even after taking them off the single stage and moving them to a Dillon 550B some 28 years ago! There's still a couple of thousandths clearance.

Edited to correct my math, doesn't seem like 1986 was that long ago!!!

 

[roc1]

Thanks again so I might get Redding dies in all my calibers FL bushing dies. I have a Hornady Match bushing die in 308 already. Sounds like all you need to do on odd mixture of brass is get loaded round measurement subtract .002 try it. I use Redding on 6.5 already along with micro bullet seater which is great if you change bullets easy to reset main thing. Standard seaters seem to work fine. Need to get shoulder bump down little better still learning always did old fashion way with std neck or FL dies. Seat to shellholder 1/4 turn more. Is each die different you cant use one die for different ctgs with just bushing change correct ex 308,243
roc1

 

[Bart B.]

Griff, I agree with the die's set position to be a few thousandths clear of the shellholder. But I think that applies to standard .125" high shellholders.

Note that Redding's competition shell holders are intended to touch the bottom of the full length sizing die quite hard when full length sizing cases. They're up to .010" higher than standard. That's how they keep the case sizing chamber the same size for every case so they all have no more than about .001" spread in case head to shoulder reference and set fired case shoulders back no more than a few thousandths or so.

Most sizing die instructions also state the die should be screwed down a bit after setting it to touch the fully raised ram/shellholder. That ensures the press "cams over" while the shellholder presses hard against the die's bottom. And it's the cause of average accuracy and short case life for most rifles. But so sized cases will fit 99.9% of all chambers safe enough to fire a few times.

 

[roc1]

What about leaving expander in bushing die? If all brass has been turned it is not needed according to Redding but use it if necks have not been turned. Looks like that would stretch necks somewhat maybe not ?
roc1

 

[Bart B.]

Roc1, full length bushing die bodies are made to be used with its specific cartridge. The bushings for each unique body will fit all cartridges using the same bullet diameter. The same .335" bushing can be used on .308 Win, .30-06, .300 Win and .300 Weatherby sizing die bodies.

Check out Redding's site on their bushing dies and shellholders:

http://www.redding-reloading.com/on...ntent&view=article&id=118:type-s-bushing-dies

http://www.redding-reloading.com/on...ew=article&id=35:competition-shellholder-sets

Redding's bushing dies don't need an expander stem in them. Case necks are best sized without them unless a smaller expander ball than normal is on them that won't touch and possibly bend the case neck on its way back up and out of the case. If you choose to decap your fired cases the same time your sizing them, then this is the best way. Otherwise, decap your fired cases then clean them before lubing and sizing them. That keeps the primer residue out of the sizing die.

You don't need to turn case necks to uniform thickness before using a full bushing die. As long as they've got less than a .002" spread in wall thickness, they're fine. If they do, turn them just enough to get the spread somewhere less than that; good enough for excellent accuracy. And they won't expand and get sized down to much each time they're fired and resized.

While Redding makes good stuff, some of their reasoning behind using it doesn't match reality. They claim the reason their bushings size only about 90% of the case neck is so the larger part next to the case shoulder that's not sized down centers it better in the chamber neck. That part of the case neck is smaller than the chamber neck and doesn't touch the chamber neck wall at all unless the case neck is way, way off center on the case shoulder. I think Redding doesn't understand that; if they do, they're catering to reloaders who also think that's reality instead of the myth it is.

 

[roc1]

Thanks again Bart understand better now I tried bushing die on 6.5 with expander cause thought you were suppose to by Redding. I want to try bushing dies on all Calibers I load to get most out of them and longer case life. Do you stay with better brass ex Norma,Lapua or just use whatever you have like Remington Winchester Hornady whatever?
Thanks again
Roc1

 

[Bart B.]

I've used Winchester or Western brass since the '60's for the most part. Some Federal, Remington or Hornady, too. Tried various case prepping that didn't do much. Weighing cases into batches with a 1 grain spread seems to help a little at long range.

 

[roc1]

Thanks so much for help I will get more Redding dies in future to try enjoy experimenting trying to get little better loads. I have good Lapua and Norma brass on couple calibers all could get. I will sort rest brass by headstamps ck with mic to see what bushing for what brass. I do have multiple rifles in 243 rest one per caliber so that will be easy. You think shellholders make setting dies lot easier more precise?
Thanks again learning lot making loading more fun again
roc1

 

[Bart B.]

I think using Redding's competition shell holders does simplify setting a full length sizing die to properly size bottleneck cases. Otherwise, you have to use a minimal amount of case lube evenly coating all the cases to keep their headspace spread under .002". That's good for excellent accuracy and long case life.

 

[steve4102]

Thanks Bart so if I reset die to touch existing Shellholder and that is not enough then you need competition shell holders to move shoulder back enough correct?
Are bushing dies better even if you don't turn necks for standard loads not competition guns?
Thanks again
Roc1

No not really.

Follow your instructions that came with your dies.

Typically you screw the die into the press until it touches the shell holder (standard shell holder) then screw the die INTO the press 1/4 turn more.

http://www.rcbs.com/downloads/instructions/ReloadingDieInstructions.pdf

From Redding.

Question: I have my Full Length Resizing Die/Body Die adjusted so that it is touching the Shellholder and I cannot push my shoulder back. Is there something wrong with my Sizing Die?



Answer: Probably not. In most instances, using Cam-Over will allow the reloader to push the shoulder back sufficiently.

To set a Full Length/Body Die up to Cam-Over:

1) Install the appropriate Shellholder into the Ram of your Press.

2) Raise the Ram so that it is in its uppermost position.

3) Screw the Full Length Resizing Die/Body Die down into the press until it firmly contacts the Shellholder.

4) Back the Ram away from the Die.

5) Screw the Die down FURTHER into your press an additional 1/8th to ¼ turn.

Note that you will feel the Ram/Shellholder contact the resizing Die before the stroke is completed. Completing the Ram Stroke will feel as though you are snapping the latch on a toolbox.

These directions apply only to standard Single Stage Presses. If your single stage press was not manufactured by Redding Reloading Equipment, please contact the manufacturer to see if using Cam-Over is appropriate for your particular Reloading Press.


http://www.redding-reloading.com/tech-line-a-tips-faqs/132-faqs1

 

[Bart B.]

Following most standard full length sizing die instructions are virtually guaranteeing three things will happen.

* All sized cases will chamber and fire.

* The accuracy it enables will be average at best.

* Case life will be minimal.

Minimally size the fired cases and all three will get better.

 

[jepp2]

Following most standard full length sizing die instructions are virtually guaranteeing three things will happen.

* All sized cases will chamber and fire.

This is excellent advice! The die maker is most interested in you not calling them to complain about how your reloads will not chamber.

If you aren't measuring when you set up your die, who knows what you will get. You sure don't know. There are many ways to do this, and many tools to assist you. But screwing the die down 1/4 to 1/2 past contact is really bad advice (unless your name is RCBS, Lyman, Lee, Redding, etc.).