Shoulder bumping technique

[fguffey]

Exactly so why would we expect shell holders to be any different.

I have one set of Redding Competition shell holders, it is the magnum set, I paid $5.00 for the set. None of the dies have been out of the box since I checked them. I measured the deck of all 5 shell holders, 3 of them was off by .001" each.

A reloaders should be able to measure the distance from the shoulder/datum of the die to the deck of the shell holder. No one does that because it is complicated.

F. Guffey

 

[fguffey]

If you cerrosafe your die you will have within .0015 of the dimension. You are better off getting a body die vs trying to use a Fl die or getting a custom die from Forster on a budget or Warner if you want top shelf

I can not get involved in cerrosafe casting, I had a weak moment and then got over it on THR. And then there was that time on the Reloaders Nest, a new member wanted to know about chamber casting, as usual he got no help from the Internet. I asked him to contact me by phone; he did and now he one of the best chamber casters, there is him and the then there are none.

Reamers for chambers and dies: That is another thing that is not possible to talk about on the Internet.

F. Guffey

 

[Svashtar]

The die doesn't have a stem so it is a body die. He said this in a 1,3 word sentence. If you're like me if the first or second word isn't tuna, marlin, striped bass or eels I'll miss it lol.

Thanks! Of course, should have noted the absence of a stem. And I replayed the beginning of the video to listen for a mention and still managed to miss it.

I've only experimented with partial FL sizing, messing with the die until I get the shoulder back .002, but it requires a lot of trial and error. This process seems much more precise and repeatable.

 

[CatShooter]

I'm expecting the exact same as if I were to grind .002" from the top of a shell holder. A little more shoulder bump

Just how much "bump" do you need??... or put a different way, just how short is your chamber??

 

[RYEWSKY25284]

I have typed 3 responses and deleted them, they may have been too advanced. Let's simplify.
First, new brass once fired historically across the board grows .004-.006" in length, once fired brass coming from your chamber does not all measure the same. So getting a real consistent bump after the first firing is hard because of that fact.
So you need a baseline number in conjunction of how fired brass fits back in your chamber. Typically I "Settle" on the bump first time, then fire brass the 2nd time and now is when the setting of the die becomes more critical.
As mentioned, a consistent lube is essential to your bump. Every lube works if done right, through trial and error, you will find one you trust. I don't want to go far on lubes, but people tend to point fingers when something goes wrong. Like blaming bad behavior on whiskey if you are a beer drinker and manage to get a big belly full of whiskey and now you have to answer for it. Whiskey and one shot bad, well, NO.
On the gap between die and shellholder, most likely flex, not slop in the press. The greater the gap, the less lube on the bottom of the case that needs it the most.
On turning the die down or up, threads are a 7/8 x 14 coarse thread, a minute turn is big. A tenth of a turn is way too much. One other thing you need to figure in is thread load between the die and lock ring when adjusting it, < Bear with me, If you want to back your die off some, you loosen the die from the press, back it off some to get some room to adjust the lock ring, now you will hold the ring down while backing the die out, pinch the 2, lock the ring, you need to the same when screwing it in also, you can't relax the load. That results in large changes.
With once fired Norma brass, you are a ways from any springback scenarios that you will encounter with more firings, You will learn as you as you go, like all of us, you are not national champ first time out of the gate. If I had known 34 yrs ago what I know today there would have been many less bumps in the road.
There are a lot of shooters in CA, try find a mentor, unless you are some type of social pariah, most people are willing to help.

The part about turning down the die and holding the lock ring is a VERY important tip. It doesn't take much to get a HUGE adjustment.
You have done a great job describing this technique.
Many Thanks.
SC

 

[Mram10us]

Just how much "bump" do you need??... or put a different way, just how short is your chamber??

So, we agree, it gives you the same affect

 

[CatShooter]

So, we agree, it gives you the same affect

No we do not...

 

[Svashtar]

The part about turning down the die and holding the lock ring is a VERY important tip. It doesn't take much to get a HUGE adjustment.
You have done a great job describing this technique.
Many Thanks.
SC

Well, I've read it several times and don't get what is being said. I use Hornady die lock rings. If I want to back the die out, I use the Hornady die lock ring wrench to back the ring and die off together how much I want, then hold the die, loosen the die lock, and tighten the ring to the new position against the press then tighten die lock ring. To crank the die down, hold the die, loosen the die lock with an Allen wrench, turn die down, retighten.

I'm not sure how else to do it, or the distinction of the point being made, but am certainly willing to be educated, thanks.

 

[Mram10us]

No we do not...

Please explain the difference between shaving a shell holder and shaving the bottom of the die.

 

[fguffey]

Please explain the difference between shaving a shell holder and shaving the bottom of the die.

Shaving/grinding the top of the shell holder and or bottom of the die is a bad habit. I size cases for short chambers meaning the chamber length from the shoulder of the chamber to the bolt face is shorter than the press, die and shell holder is capable of sizing.

I could grind the bottom of the die to increase the presses ability to size the case, I could also shim the case head up and off the deck of the shell holder when sizing cases for short chambers.

More times than not the reloader grinds the die and or shell holder because he does not understand why the press, die and shell holder will not size a case. I increase the presses' ability to size a case with a 'no-name- lube. This stuff is as slick as okra. I only use it when sizing/forming the toughest cases to size and or form. I have to be careful when lowering the handle, I have to make sure I do not exceed the recommend operating speed.

When sizing a difficult to size case I check to see of the die made it to the shell holder, if the die does not make it to the shell holder there will be a gap.

F. Guffey

 

[fguffey]

Out of curiosity i just measured 3 different shell holders:Lyman=.084
Redding= .122
RCBS=.121
Guess they do differ. That's why I originally bought several to have some adjustment room with my dies!?!

If those shell holders belong to me I would want my money back. The RCBS shell holder would allow the user to size cases for a go-gage length chamber + .004". there has to be something seriously wrong with the Lyman if it is a modern shell holder.

Again, C&H sold dies in fiber boxes many years ago. C&H printed the instructions on the bottom of the fiber box. They suggested the dies in the box should be used with shell holders with a height of .125".

They did not suggest their dies should be used with C&H shell holders. If there is something that is 'all over the place' in reloading it is the reloader.

F. Guffey

 

[jes10x1]

I would take a look at the attachment on the Forster bushing bump sizer die

 

[Mram10us]

Shaving/grinding the top of the shell holder and or bottom of the die is a bad habit. I size cases for short chambers meaning the chamber length from the shoulder of the chamber to the bolt face is shorter than the press, die and shell holder is capable of sizing.

I could grind the bottom of the die to increase the presses ability to size the case, I could also shim the case head up and off the deck of the shell holder when sizing cases for short chambers.

More times than not the reloader grinds the die and or shell holder because he does not understand why the press, die and shell holder will not size a case. I increase the presses' ability to size a case with a 'no-name- lube. This stuff is as slick as okra. I only use it when sizing/forming the toughest cases to size and or form. I have to be careful when lowering the handle, I have to make sure I do not exceed the recommend operating speed.

When sizing a difficult to size case I check to see of the die made it to the shell holder, if the die does not make it to the shell holder there will be a gap.

F. Guffey

There is nothing wrong with taking a little off either if needed. You can choose your own technique but cannot logically say it's a bad habit

 

[BountyHunter]

To make it clear lets look at the 6.5 creedmoor to help understand the issue. SAAMI specs give a +- of .010 on the shoulder specs for this cartridge. Others can be as low as .007. In other words IF your chamber is absolutely within SAAMI dimension there can be a .010 shoulder variance from one gun to the other. Ammo has to be minimal SAAMI at max dimensions so it will fit ANY gun. Add a worn die reamer and you could add another .002 variance. Did the mftr or gunsmith run the chambering reamer in .002 too long? That is why "basic" die instructions are written for the novice and are set up for cam over to get back to factory SAAMI specs. Their lawyers make them set the instructions up that way. That also means just doing cam over may work and may not by itself.

Now let's say you take a sizing die and set it down on the shellholder (again you must assume that they are all the correct height but I have seen .008 variance). I have an RCBS rockchucker and I do not care if you are Magilla Gorilla once metal meets metal that is all the compression and shoulder bump you are going to get. Period!!!!! Now IF you are lucky and IF you can actually measure shoulder bump you might be within .002 of the chamber shoulder. You could also in actuality be about .008 or more off. Again, think about it, that is why Redding has the competition shellholders that offer .0010 of adjustments in .002 increments for the guys hung up on shoulder bump or has dies that are a shade too long for correct bump. Keep reloading that same case time after time at that distance and you will eventually get case head separation. Think about this, how is it even possible to get case head separation IF cam over works perfect every time?

There is a reason the top two factory die mftrs (Whidden and Redding) give specific instructions for adjusting the dies for optimal shoulder bump and max case life to back off 1/3-1/2 turn and work your way down. On most dies 1/8 turn is about .009 of actual movement on the shoulder. The new Whidden dies have a .001 click adjustment built in for that reason.

Whidden die instructions are to back off and come down. Here is a composite of the Redding die instructions saying same thing for max precision. IF we bother to read the instructions they actually give you two techniques for sizing; one for general use in ANY firearm and one for precision.

"Just" getting cam over is for returning back to factory specs and the novice. Period

I have had shellholders that were .008 variance from the .125. That is why one shellholder goes in each die box and stays with that set of dies ONLY.

Skip Otto die shims are cheap and your friend especially if one set of dies and two guns. Try them.