Which is exactly what I was trying to get at, just didn't seem to know the right way to put it. I've seen countless posts/claims by ppl stating that you can "only bump shoulders" using a FL die - and that just didn't make sense to me...From the teachings of Mr. Guffey
it is impossible to bump a shoulder using a Die with full body support.
Let that stew for a couple minutes
Tick Tick Tick
case sizing ?
- Thread starter rebs
- Start date
While it's often not speaking accurately, speaking colloquially does help best to convey what's going on to those who don't have a full grasp of the technical jargon . . . huh???
BoydAllen
Gold $$ Contributor
In a thread where new reloaders are looking for help, this sort of stuff is hardly helpful. It just increases confusion among those who are already confused. For the record, the statement if absolute crap.From the teachings of Mr. Guffey
it is impossible to bump a shoulder using a Die with full body support.
Let that stew for a couple minutes
Tick Tick Tick
BoydAllen
Gold $$ Contributor
I disagree completely. Shoulders are most commonly bumped by FL dies that give full body support, and riddles are hardly helpful when someone is looking for answers. You seem to be playing with words for your own amusement, certainly not to help new reloaders. IMO Guffey was not trying to be helpful as much as he was looking for attention and to stir the pot to the maximum. Wait...wouldn't that be trolling?
BoydAllen
Gold $$ Contributor
Your question has little to do with the issue. A FL die does not become less supporting of the case body by using a short shell holder, and not all chamber die combinations require a modified shell holder. In fact some of the bumping problems that fellows post about are caused by their trying to bump cases that have reached the maximum shoulder to head dimension for that rifle. They are trying to bump a case that does not need it. They think that they need to bump once fired brass when in most cases it is not necessary. As a reminder, we only bump to create clearance, when and if it is needed. On the custom shell holders, I do not see anyone offering them shorter than standard. Reddings are taller. I have either made my own, or had a friend with a lathe do it. As far as I know, there is no off the shelf source, or anyone who advertises this service. Again, you are talking apples and oranges. Needing a modified shell holder has nothing to do with whether a die gives full body support.
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Dusty Stevens
Shiner
A die with full body support can bump shoulders as far as you want to. It goes out the top. Guffey was wrong and i hate that he trolled you jim. Guffey isnt an expert reloader even by his standards. The things he taught and thought he invented people quit doing back in the 40’s
This is a case of taking something simple and making it complicated.
Full length sizing properly performed sets the shoulder back just enough to chamber the case with slight resistance. The goals is to provide optimum case fit (sizing) for a specific rifle.
Before gauges old timers accomplish this using a manual method of sizing the case with no cam over checking fit in the rifle then gradually turning the die down to increase cam over slightly until the optimum fit is achieved then locking the die in place for reloading. This only works for a case fired in the specific rifle you are loading for since each rifle may and probably has different head spacing. An easy way to adjust for other rifles of the same caliber is using Skip's Shims to change the degree of cam over.
The manual method still works fine although I prefer to use a gauge to measure shoulder set back. I set my die to bump the shoulder back .001 to .002" (bolt rifles). Full Length resizing in this manner does not reduce case life or degrade accuracy in my experience in loading thousands of rounds. This manner of sizing also, most importantly for me since I'm a year around hunter, promotes reliable chambering - obviously critical in the field.
As far as neck tension, in my experience many of the expander balls on RCBS dies are over sized creating considerable drag on the case neck. This can be remedied by carefully polishing the ball and measuring to produce the desired amount of neck expansion and neck tension. In fact I have several for each caliber with different dimensions.
German Salazar wrote an excellent article on the virtues of properly full length resizing explaining the reasons that this method produces more uniform reloads. Unfortunately I don't think his blog is available anymore.
Bottom Line: I my humble opinion you can produce very accurate, safe and reliable reloads using standard RCBS full length resizing dies. Several of my custom barrel varmint rifle hold 5 shot groups in the 1/4 to sub 1/4 moa range.
Full length sizing properly performed sets the shoulder back just enough to chamber the case with slight resistance. The goals is to provide optimum case fit (sizing) for a specific rifle.
Before gauges old timers accomplish this using a manual method of sizing the case with no cam over checking fit in the rifle then gradually turning the die down to increase cam over slightly until the optimum fit is achieved then locking the die in place for reloading. This only works for a case fired in the specific rifle you are loading for since each rifle may and probably has different head spacing. An easy way to adjust for other rifles of the same caliber is using Skip's Shims to change the degree of cam over.
The manual method still works fine although I prefer to use a gauge to measure shoulder set back. I set my die to bump the shoulder back .001 to .002" (bolt rifles). Full Length resizing in this manner does not reduce case life or degrade accuracy in my experience in loading thousands of rounds. This manner of sizing also, most importantly for me since I'm a year around hunter, promotes reliable chambering - obviously critical in the field.
As far as neck tension, in my experience many of the expander balls on RCBS dies are over sized creating considerable drag on the case neck. This can be remedied by carefully polishing the ball and measuring to produce the desired amount of neck expansion and neck tension. In fact I have several for each caliber with different dimensions.
German Salazar wrote an excellent article on the virtues of properly full length resizing explaining the reasons that this method produces more uniform reloads. Unfortunately I don't think his blog is available anymore.
Bottom Line: I my humble opinion you can produce very accurate, safe and reliable reloads using standard RCBS full length resizing dies. Several of my custom barrel varmint rifle hold 5 shot groups in the 1/4 to sub 1/4 moa range.
Absolutely correct Dusty. I encourage everyone to take some time and experiment with good measuring tools during different stages of full length resizing. That shoulder goes forward before it goes backward, even the type of lube makes a difference on how things move.
I hope you don't mind if I cut the Goofy Guffy stuff off. Think simple guys because that's what happens.
Dusty Stevens
Shiner
Its hard to believe but with good dies you can adjust your bump with lube. Some will never see the light and be blessed with good dies. They truly are a pleasure
rwj
Gold $$ Contributor
Yes. This is why I don’t size the body and neck simultaneously. Constraining the neck resists material flow and encourages donut formation. I’ve not experienced any significant difference in case neck/body concentricity using a two step process. I do admitted have the time required
!most often , bumping is less press stroke than full length sizing (meaning longer finished shoulder measurement) , you just have to wait until your brass has grown to match the chamber to bump it .
sometimes, i think new reloaders read that bumping brass is a necessary procedure , and they dont even have fully formed brass yet
when would you ever need to size less than "full body support" anyways
but just for giggles , lets say that a guys chamber was headspaced to the very minimum , the most minimum of all the rifles on the planet ( but can still chamber a saami factory round ) if this guy bought some once fired brass that the case body was longer than his chamber , this "full body support" idea prevents this guy from bumping this once fired brass to match his chamber ???
full body support idea ?? no , does not compute
brass is soft and its gonna move somewhere. full length sizing ... will either squish compress , fill the sidewall shoulder corner , or start building donuts out the neck .. it will move , if it springs back , move it more until it springs back to where you want it
**** its not really a riddle if it has no answer ****
sometimes, i think new reloaders read that bumping brass is a necessary procedure , and they dont even have fully formed brass yet
when would you ever need to size less than "full body support" anyways
but just for giggles , lets say that a guys chamber was headspaced to the very minimum , the most minimum of all the rifles on the planet ( but can still chamber a saami factory round ) if this guy bought some once fired brass that the case body was longer than his chamber , this "full body support" idea prevents this guy from bumping this once fired brass to match his chamber ???
full body support idea ?? no , does not compute
brass is soft and its gonna move somewhere. full length sizing ... will either squish compress , fill the sidewall shoulder corner , or start building donuts out the neck .. it will move , if it springs back , move it more until it springs back to where you want it
**** its not really a riddle if it has no answer ****
Guffy talks in riddles but there is truth there.
We don't actully move the shoulder as it is. We actually relocate the shoulder a thousandth or two down the case. A tiny piece of case wall becomes shoulder and a tiny piece of shoulder becomes neck. When fired the process is reversed.
As this cycle is repeated shoulder brass migrates into the neck. Since it is thicker that is where donuts come from. The less your sizing process moves the brass around the longer it takes to migrate. It is also why when you turn necks they always reccomend cutting into the shoulder. It thins that brass the someday will become shoulder.
We don't actully move the shoulder as it is. We actually relocate the shoulder a thousandth or two down the case. A tiny piece of case wall becomes shoulder and a tiny piece of shoulder becomes neck. When fired the process is reversed.
As this cycle is repeated shoulder brass migrates into the neck. Since it is thicker that is where donuts come from. The less your sizing process moves the brass around the longer it takes to migrate. It is also why when you turn necks they always reccomend cutting into the shoulder. It thins that brass the someday will become shoulder.
BoydAllen
Gold $$ Contributor
Since the subject of one piece RCBS dies has been broached, let me make one suggestion, assuming unturned brass. Measure the OD of the neck of a case fired in your rifle at a specific distance from the shoulder where the shank of the bullet will be after seating. Size it normally with the expander ball in place and measure it in the same place. Seat a bullet and measure it again, in the same place. Finally, pull the bullet, remove the decapping assembly from the die size the case again, and do the same measurement. Based on my experience, what you will see is that the ID of the neck portion of the die is a lot smaller than necessary for unturned necks, by a lot. In the past I have used these dies as the basis for designing chamber reamers that were for turned necks. and which produced wonderful results. I chose a neck thickness that had the neck OD of the die working like a perfectly chosen bushing for benchrest, imparting just the right neck tension, and chamber body dimensions such that fired brass would be reduced in diameter only enough so that cases would chamber without resistance. Years ago, I did a little research and was told that RCBS one piece sizing dies are designed to produce body dimensions that are at SAAMI minimum for loaded ammunition. Lee dies are built to SAAMI maximum for loaded ammunition. These days, I generally avoid one piece sizing dies unless I am working with a custom chamber was designed for one, or it is a custom die. In both of those cases, one piece dies will generally produce slightly straighter brass than bushing dies, but the difference is not so great that it shows up on my targets.
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A honed forster die won't
And whidden makes an expander ball kit that lets you control neck tension very well. I have a whidden full length sizer with the expander ball kit. It makes very straight reloads with great control over neck tension. All the benefit of a bushing die without all the problems.
I absolutely agree with your last sentence and I have been at this a very long time also Boyd. Good info for progressing handloaders.
Hey Rebs how you doing ? I think cw308 is on to something . Load some of each and see what shoots better . I would ask what firearm or type of firearm you are loading for ? If semi auto I'd recommend you not neck size only . Semi auto's generally have less cam force when the lugs lock up and if you don't FL size your cases you can have feeding issues .
As for what is bumping the shoulder and FL sizing . IMHO FL sizing is when you use a standard size shell holder and have firm contact between the die and shell holder with cam over if applicable at the top of the stroke . That right there will FL size your case . Anything less then that is bumping the shoulder back to a specific location/distance . Now that might not be accurate or true but that's how I think of it .
FL sizing could also mean sizing the body the full length of the case . In theory one can FL size a case and actually not move the shoulder back or even actually move it forward some when using that definition .
As for what is bumping the shoulder and FL sizing . IMHO FL sizing is when you use a standard size shell holder and have firm contact between the die and shell holder with cam over if applicable at the top of the stroke . That right there will FL size your case . Anything less then that is bumping the shoulder back to a specific location/distance . Now that might not be accurate or true but that's how I think of it .
FL sizing could also mean sizing the body the full length of the case . In theory one can FL size a case and actually not move the shoulder back or even actually move it forward some when using that definition .
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