The Accurate Reloading Forums
PARTIAL FL SIZING
23 March 2010, 05:46
BISCUTPARTIAL FL SIZING
i lost my cheat sheet on partial fl sizing to bump the shoulder back .002. for some reason i am not setting up my fl die correctly. what is your procedure to set up your fl die for this opertion? i am using redding dies.
23 March 2010, 05:51
steve4102This is a copy of how our friend HotCore explains it.
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 squash 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
23 March 2010, 18:21
BISCUTThank you much Stevo

24 March 2010, 01:17
rcamugliaquote:
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.
Shouldn't this read "screw the die
out of the press" or "
back the die away from the shellholder"?
24 March 2010, 02:15
Jim C. <><Ideally you will have a gage of some type to actually measure where the fired and resized shoulders are; Hornady/Stoney Point, Sinclair, RCBS Precision Case Mic or the Innovative Technologies shoulder tools work fine.
I don't think there's any reason to set the shoulders back at all from fired length. They have already shrunk down a tad from max chamber dimensions, sizing them back any further only increases case stretch.
24 March 2010, 02:43
Hot Corequote:
Originally posted by rcamuglia:
quote:
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.
Shouldn't this read "screw the die
out of the press" or "
back the die away from the shellholder"?
If you did #2, it is unlikely. The Die just isn't into the Press far enough, to resize the Case Walls, to cause the Datum Point on the Shoulder to move forward enough(lengthen the Case), to cause an interference fit.
But..., some of this depends on the actual Chamber Dimensions as well as the FL Die Dimensions. What you suggest is possible, but unlkiely.

24 March 2010, 06:39
woodsquote:
Originally posted by Hot Core:
quote:
Originally posted by rcamuglia:
quote:
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.
Shouldn't this read "screw the die
out of the press" or "
back the die away from the shellholder"?
If you did #2, it is unlikely. The Die just isn't into the Press far enough, to resize the Case Walls, to cause the Datum Point on the Shoulder to move forward enough(lengthen the Case), to cause an interference fit.
But..., some of this depends on the actual Chamber Dimensions as well as the FL Die Dimensions. What you suggest is possible, but unlkiely.
That's where you need a "thingy" to tell you!!

If you had an appropriate modern infallable esteemed gauge "thingy", you would be able to tell if you have gone too far or not far enough yet.
Now wiggle out of that one HC!

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24 March 2010, 06:59
Cover DogThis article by German Salazar should help.
http://riflemansjournal.blogsp...ading-headspace.html24 March 2010, 07:02
Rae59Your chamber & bolt is your guage/thingy.
"The right to bear arms" insures your right to freedom, free speech, religion, your choice of doctors, etc. ....etc. ....etc....
-----------------------------------one trillion seconds = 31,709 years-------------------
24 March 2010, 09:15
Not_InfringedThis is great info!
Does this technique (with or without the fancy headspace gauges) apply to a semi auto rifle, or just bolt action weapons?
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24 March 2010, 17:15
Hot Corequote:
Originally posted by Rae59:
Your chamber & bolt is your guage/thingy.

Hey Woods, Mr. Rae nailed it. Don't even need the Bailer Wire and Duct Tape(but it is nice to have for an emergency

).
24 March 2010, 17:26
Hot Corequote:
Originally posted by Not_Infringed:
Does this technique (with or without the fancy headspace gauges) apply to a semi auto rifle, or just bolt action weapons?
Hey NI, You need a bit more Headspace with Semi-Autos so they continue to Feed properly. If the Case is "Snug" in them, there is about a 99.99% chance that the Bolt will not fully move into Battery(not lock-up

).
So, it is best to Full Length Resize Cases for Semi-Autos and then watch for the Insipient Case Head Separation with the old sharpened-edge, Bent Paper Clip Feeler Gauge(NOTE: It does not meet the
"Thingy" Design Requirement of ripping your head off in cost.

)
Mild Pressure Loads that cycle the action and Full Length Resizing help Semi-Auto case life considerably. And, you can prove it to yourself by trying anything else.
Best of luck to you.
24 March 2010, 17:29
steve4102But, with the thingy you only need to use the barrel/firearm once. After you get the proper "crush" fit and or shoulder bump, measure the case with the thingy, record this measurement and your done. Much easier to have a small thingy on my bench then a big ass rifle just to check the head-to-shoulder measurement of my brass.
24 March 2010, 18:34
Jim C. <><quote:
Does this technique (with or without the fancy headspace gauges) apply to a semi auto rifle, or just bolt action weapons?
It is virtually impossible to properly adust a die for an autoloader by "feel" so it's necessary to get a tool OR just fully cram cases into the die as Steve says.
A "crush fit" suggests a tight chambering effort. That's rarely helpful to accuracy even with a bolt rifle, it's usually better to have cartridges sized to allow easy chambering but with little or no extra headspace.
Every reloader needs a dial/digital caliper anyway. Purchasing the Hornady LnL case headspace tool for a caliper costs less than a new die set, and it's well worth the price.
24 March 2010, 22:54
rcamugliaquote:
Originally posted by Hot Core:
quote:
Originally posted by rcamuglia:
quote:
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.
Shouldn't this read "screw the die
out of the press" or "
back the die away from the shellholder"?
If you did #2, it is unlikely. The Die just isn't into the Press far enough, to resize the Case Walls, to cause the Datum Point on the Shoulder to move forward enough(lengthen the Case), to cause an interference fit.
But..., some of this depends on the actual Chamber Dimensions as well as the FL Die Dimensions. What you suggest is possible, but unlkiely.
Here's what I do, and it may be wrong:
I chamber a fired case, if there is a slight crush fit, I load them after neck sizing only. If the bolt takes too much effort to close, I screw the die
down into the press very slightly and size the case again. I try it in the chamber. If bolt closing is easier or where I want it, I leave the die set there and size all the brass to load.
You really need to take the firing pin and ejector (plunger type) out of the bolt to check this "crush fit" because when you close the bolt with them in, there is slight resistance even on an empty chamber. It's tough to tell the difference between the resistance of the crush fit of the case or the cocking mechanism/ejector.
27 March 2010, 02:11
Rae59Quote: You really need to take the firing pin and ejector (plunger type) out of the bolt to check this "crush fit" because when you close the bolt with them in, there is slight resistance even on an empty chamber. It's tough to tell the difference between the resistance of the crush fit of the case or the cocking mechanism/ejector.[/QUOTE]
------------------------------------------------
Not if it has a three position bolt safety as in Winchester M-70 or Ruger M-77, or Kimber M-84, etc.
"The right to bear arms" insures your right to freedom, free speech, religion, your choice of doctors, etc. ....etc. ....etc....
-----------------------------------one trillion seconds = 31,709 years-------------------
27 March 2010, 07:02
ted thornI use to use the feel method that is described above but now use a "thingy" or a gauge to set up for shoulder bump. This allows me to absolutely know what the length is to the C/L of the shoulder. This is very cool because you can see just for shits-and-grins just how much factory new brass streches the very first shot.
My gauges are custom made by myself for each family of cases and uses a full radius to contact the shoulder at the mid-point. By doing this I have a measurable check and for me, I need/want that.
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