Trying to bump the shoulder back

[Woodsie]

I'll probably feel like an idiot for this but here it goes...I've been reloading for a while but only neck sizing and full length. Now for the first time I'm trying to just bump the shoulder back a little and I can't seem to get it figured out. I'm using a Lee full length die in a Rock Chucker. 7mm magnum. First I set the die up like normal...1/4 turn more after it hits the shell holder. That bumps the shoulder back .012. I wanted to try getting that to .002, so I figured I'd just back the die out until I get there. But as I do this nothing changes. I'm using a Hornady headspace gauge to check this. I've searched through all of my manuals and everywhere else I can think of but I've had no luck. So please tell me what I'm doing wrong here.

Thanks

 

[burrhead]

Unscrew the die a full turn then start your try and error. You'll get there eventually.

 

[rsrocket1]

Ditto for what burrhead said. What you are doing with the Lee FL die is called paradoxically "partial full length resizing" in order to bump the shoulder back. You typically only need to do this if the shoulders move up after several neck sizing shots. The downside of this is that you are undersizing the neck then expanding it again when you pull the expander ball out. You must go through this whole process by trial and error because when you pull the expander ball out, it can also stretch the entire case including the shoulder and you must account for this when adjusting the die.

Once you get this all dialed in. Mark the positions of your die and lock ring against an index position of the press with a magic marker and you won't have to readjust your settings by trial and error again.

 

[Woodsie]

Thank you

 

[JDGray]

Get a body die from Redding to make life way easier. I don't care for Lee FLS dies as they over work the shoulders by under sizing the necks so far. Follow up with the Lee neck die, which do work well.

 

[Walkalong]

.012 is way too much.

Use a carbide expander button, or lube the necks, or both, or use a bushing style FL or neck only sizer. Many use the body die along with a bushing style neck only sizer.

 

[JimKirk]

Partial Full Length sizing is all I use on all my rifle cartridges except the .223 Remington .... once you get the feel for it it will work well.... the best way to get to that magic point is by using your rifle's chamber not a gauge .... your chamber may be close to the gauge or it may be way off .... that is why I never use a case gauge except for the AR .223 ... size until the bolt just closes with a faint hint of resistance .... that is the closest you will get to neck sizing but moving the shoulder back enough to fit the chamber...

If you shoot the same ammo in multiple guns ... you will have to size to fit the smallest chamber or keep the ammo separate which is the best way...

 

[MtnCreek]

Get some Lyman or Forster die rings. They lock in place well.

 

[fguffey]

I'm using a Lee full length die in a Rock Chucker. 7mm magnum. First I set the die up like normal...1/4 turn more after it hits the shell holder. That bumps the shoulder back .012. I wanted to try getting that to .002, so I figured I'd just back the die out until I get there. But as I do this nothing changes

Adjusting the die according to the instructions is conditioning. Reloaders are conditioned to follow instructions. Problem with sizing belted cases. The belted case head spaces on the belt, the length of case from the shoulder to bolt face is of little consequence.

Meaning the reloader has to decide if he is going to size the case to head space off the belt or the shoulder of the case. I would suggest you measure the length of the case from the shoulder to the head of the case before firing, if the case is increasing in length by .012" your chamber has serious problems for a reloader that full length sizes case to head space off the belt.

I have one rifle that has a chamber that allows a case to head space on the belt and shoulder at the same time. I have another rifle with the same chamber that had the ugliest chamber I have ever seen. Both rifles were new and using the same ammo. One shot one hole groups, the other shot like a shotgun, it shot patterns.

F. Guffey

 

[quartermaster]

Try taking the expander and decapping rod out of your FL sizing die. Then screw the die down until it touches your shellholder and forget the extra 1/4 turn. Back it off 1/4 to 1/3 turn and size, turning the die down until you get the shoulder set back .002 more than a fired case. When you get it right, lock the die ring in place, and install the expander and decap rod and try to chamber the case.

My 7 Mag won't chamber after 2 reloadings doing this as the case base does not get sized enough above the belt, so I bought the belted magnum collet die from Larry Willis's web site and that solved my problem. All is good now!!! QM

 

[steve4102]

This is how an Old timer explained to me many years ago how to set up FL dies with little to no bump.


1. Put the Shell Holder in the press and raise the ram.

2. Screw the Full Length(FL) Die into the press so it is about a "nickle's thickness" above the Shell Holder.

3. Lube a "Fired" case (walls and inside the neck) and size it.

4. Remove the Lube and try closing the bolt on it in the chamber.

5. If the bolt closes with no resistance, screw the FL Die into the press about 1/8-1/4 turn and repeat steps 3 & 4.

6. As you feel the resistance begin, slow down how much you screw the FL Die into the press so you are at about 1/16 of a turn, or "Fine Tuning". At some point you will not be able to close the bolt and you are extremely close to having the FL Die in the proper position.

NOTE: The reason for this is because the FL Die has begun Resizing the Case-walls down to the Pressure Ring. As it does so, the Case-body lengthens slightly which in turn moves the Case-shoulder slightly forward. Then as the "Fine Tuning" continues the Case-shoulder makes contact with the FL Die and is moved slightly reward(or slightly shortens the Case-head to Case-shoulder dimension).

7. Stop when there is a slight bit of resistance when closing the bolt on the empty case. You now have a "slight crush fit" for the case in that specific chamber, or Zero Headspace.

8. Once you get it where you want it, take some masking tape or a black marker and put a Witness Mark where the FL Die Lock Ring is positioned to hold the FL Die in this position. Loosen the FL Die and return the Lock Ring to align with the Witness Mark and sung up the Set-Screw.

Screw the FL Die back into the press and try squashing another case. It should have the same resistance as the previous one. If not, you need to re-adjust the Lock Ring so it does. But you are extremely close to where you want it, so make very small changes at this point.

Occasionally check the fit of the cases in the chamber, say every 5th firing just to make sure nothing has slipped. Checking more often won't hurt anything and give you confidence that the Set-Up is still proper.

You have now Set-Up the FL Die to P-FLR and will have the very best opportunity at having long case life and the very best accuracy possible.

If you are hunting in Dangerous Game country, you should forget P-FLRing or Neck Sizing, and always Full Length Resize so the case chambers and extracts easily.

Best of luck to

 

[fguffey]

First I set the die up like normal...1/4 turn more after it hits the shell holder. That bumps the shoulder back .012.

If it was a case fired in my chamber I would have measured the length of the case before firing and again after firing. The length of the case before firing would indicate the length of a case that would allow the bolt to close, and that is all.

Once I found the fired case increased in length .012" from the shoulder to the head of the case I would adjust the die off the shell holder, how much? I would adjust the die off the shell holder .010", I would use a feeler gage, after sizing a few cases I would attempt chambering the cases. If the bolt closed with slight resistance I would decrease the gap. If the bolt closed with no resistance I would increase the gap to .012".

F. Guffey