24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
Partial Full Length Sizing/Bumping the shoulder #15236481 09/18/20
Joined: May 2003
Posts: 669
300Winnie Offline OP
Campfire Regular
OP Offline
Campfire Regular
Joined: May 2003
Posts: 669
I am really confused....starting to feel like I’ve begun to forget what I thought I once knew.

For those that have read my recent posts you know I’m working on a load for my son’s .300 Win Mag.

We bought 100 brand new Hornady brass and all have been fired once now. In an effort to make his brass last as long as possible and potentially produce marginally more accurate ammunition I decided to set his die up to PFLR. I have the old Stoney Point headspace tool and my comparator body and measured a few cases and got a “base to datum line” measurement of 4.276” (this isn’t absolute as I don’t zero the calipers), so knew that to get a .002-.003 bump my new base to datum line measurement would need to be 4.273-4.274”

As I set out to do this I screwed my die out from the cam over setting to FLR and started sizing. The brass elongated to 4.280+\- pretty quick and stayed there for most of the adjustment.....right up to the end. When I finally got down to where it was supposed to be my die was camming over significantly...in essence what appeared to be FLRing.

Out of curiosity I decided to see what one of the cases that measured 4.280” would do in the chamber and in my opinion it had the nice snug fit I’m actually looking for.

I know that it can’t be right....no way I elongated it .004 and have it fit.

What am I missing? What did I do wrong?

BP-B2

Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15236499 09/18/20
Joined: Jun 2004
Posts: 34,505
M
mathman Offline
Campfire Oracle
Offline
Campfire Oracle
M
Joined: Jun 2004
Posts: 34,505
Brass can come out of the chamber shorter/smaller than the chamber.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15236559 09/18/20
Joined: May 2003
Posts: 669
300Winnie Offline OP
Campfire Regular
OP Offline
Campfire Regular
Joined: May 2003
Posts: 669
Size by feel in that case...hence the longer measurements to get a snug fit?

Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15236656 09/18/20
Joined: May 2003
Posts: 669
300Winnie Offline OP
Campfire Regular
OP Offline
Campfire Regular
Joined: May 2003
Posts: 669
After reading a bit more on the subject and taking Mathman’s comments I’m wondering if the measurement on the fired cases, before running through a die are actually where it needs to be...if 4.280” is a slight crush fit then .002-.003” setback would put it right back at fired case dimensions.

Am I thinking correctly or off my rocker?

Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15237150 09/19/20
Joined: May 2014
Posts: 4,535
Bugger Offline
Campfire Guide
Offline
Campfire Guide
Joined: May 2014
Posts: 4,535
Maybe you're over thinking it. The only length I am concerned about is over all length. I'll trim if necessary.

I often will not touch the shoulder with a full length sizing die. But if the re-sized case enters the chamber with more force than I like I'll bump the shoulder. I barely bump the should, turning the die down about an 1/8 of a turn until the case enters the chamber easier.


Life member NRA
I prefer classic.
Sgt USMC - a few years ago
IC-A

Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15237246 09/19/20
Joined: Jul 2014
Posts: 157
R
rabst Offline
Member
Offline
Member
R
Joined: Jul 2014
Posts: 157
I think I'd go by feel as well. If you think it feels too snug, you can then bump it back a touch.

I'm sure that you know this, but we're talking about half the thickness of a sheet of paper here to get to 0.002", three quarters to get to 0.003". Tiny fractions.


Last edited by rabst; 09/19/20.
Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15237557 09/19/20
Joined: Oct 2003
Posts: 11,450
Dave_in_WV Offline
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Oct 2003
Posts: 11,450
Smoke a case neck and with the die set out so the die doesn't contact the shell holder start screwing the die in until the soot is wiped off the neck just at the neck shoulder junction and lock the ring there.


The Karma bus always has an empty seat when it comes around.- High Brass
Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15237846 09/19/20
Joined: Sep 2006
Posts: 1,576
D
DonFischer Offline
Campfire Ranger
Offline
Campfire Ranger
D
Joined: Sep 2006
Posts: 1,576
I think you are over thinking it. Belted case's sometime's come with rifles with sloppy chamber's. That's where partial sizing really come's in handy. First reload just neck size staying above the shoulder. Second, if the fired case will chamber, do the same thing. That case probably won't chamber on the third loading. BTW, you can see how far down the neck your sizing without soot on the neck. When you have reached that point, start setting the die down a bit at a time feeling for the shoulder to rub. It will be distinct rubbing. Keep going down till the shoulder no longer rubs in the chamber. At that point the case fit's your chamber. Some claim what has actually happened is you moved the headspace to the shoulder. But, that belt is still there and now it should headspace on the belt and the case will fit the chamber. Don't be confused, all your actually doing is making the case fit the chamber of that rifle if, the chamber was sloppy to begin with. I learned it on a 7mm Rem Mag years ago. After a couple firing's I could see the ring around the case head the indicate's head separation is on the way. And in doing that with that 7mm mag, I went to doing it on all my cartridge's. Just an example of different chamber's, I have two 243's. Only tie in my life I've ever had two rifle's in the same cartridge. Both rifles have their own FL die set so that both can be adjust to the rifle with a deticated die that once set, I never move. Reloads for one of the rifle's will fit in both rifles but reloads from the other will not chamber in the first! Simply the difference made from min and max chamber size's and both could be loaded with simple die adjusting instruction that came with the die.Does one way out shoot another? Not really a clue about that. Both rifles shoot pretty consistent 1/2" groups at 100yds using different bullet's in each. Only way I'd know if it improved the larger chamber rifle would be to reset the die and start load development all over again, I'm not going to do that, think I'll simply live with what I have!

I have never had tool's to measure chamber's with and not even for seating bullet's. Never has been even a remote need for me. I think the deeper we get into measuring this and that the more we get into the science of it and few are actually trained to actually understand what all that means.

Re: Partial Full Length Sizing/Bumping the shoulder [Re: Dave_in_WV] #15238852 09/19/20
Joined: Jun 2004
Posts: 34,505
M
mathman Offline
Campfire Oracle
Offline
Campfire Oracle
M
Joined: Jun 2004
Posts: 34,505
Originally Posted by Dave_in_WV
Smoke a case neck and with the die set out so the die doesn't contact the shell holder start screwing the die in until the soot is wiped off the neck just at the neck shoulder junction and lock the ring there.


That method can lead to hard chambering.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
Re: Partial Full Length Sizing/Bumping the shoulder [Re: mathman] #15239311 09/19/20
Joined: Oct 2003
Posts: 11,450
Dave_in_WV Offline
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Oct 2003
Posts: 11,450
Originally Posted by mathman
Originally Posted by Dave_in_WV
Smoke a case neck and with the die set out so the die doesn't contact the shell holder start screwing the die in until the soot is wiped off the neck just at the neck shoulder junction and lock the ring there.


That method can lead to hard chambering.

How so?


The Karma bus always has an empty seat when it comes around.- High Brass
IC-B

Re: Partial Full Length Sizing/Bumping the shoulder [Re: Dave_in_WV] #15239343 09/19/20
Joined: Jun 2004
Posts: 34,505
M
mathman Offline
Campfire Oracle
Offline
Campfire Oracle
M
Joined: Jun 2004
Posts: 34,505
The body section of the die can squeeze the case in such a way that the shoulder, and hence the shoulder/neck junction, moves forward. So when the length of the neck is sized and the mark stops at the junction the shoulder is forward of its best position.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15239355 09/19/20
Joined: Jun 2004
Posts: 34,505
M
mathman Offline
Campfire Oracle
Offline
Campfire Oracle
M
Joined: Jun 2004
Posts: 34,505
I have a number of FL size dies for 308 Winchester. The Hornady sizes the body the most, reducing the diameter and imparting more taper to the body section of the case. I've used it to lengthen the head to shoulder distance of some brass to better fit a deeper chamber. If I used the smoke and stop method with this die in the original rifle the brass would chamber hard for sure.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
Re: Partial Full Length Sizing/Bumping the shoulder [Re: mathman] #15240056 09/20/20
Joined: Oct 2003
Posts: 11,450
Dave_in_WV Offline
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Oct 2003
Posts: 11,450
Originally Posted by mathman
The body section of the die can squeeze the case in such a way that the shoulder, and hence the shoulder/neck junction, moves forward. So when the length of the neck is sized and the mark stops at the junction the shoulder is forward of its best position.


Thank you for your reply. I have done what I posted for a few rifles but I checked the brass for ease of chambering. Doing what I posted and checking the brass in the chamber and turning the die down if necessary would work wouldn't it?


The Karma bus always has an empty seat when it comes around.- High Brass
Re: Partial Full Length Sizing/Bumping the shoulder [Re: Dave_in_WV] #15240161 09/20/20
Joined: Jun 2004
Posts: 34,505
M
mathman Offline
Campfire Oracle
Offline
Campfire Oracle
M
Joined: Jun 2004
Posts: 34,505
It should.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15240174 09/20/20
Joined: May 2003
Posts: 15,008
S
Spotshooter Offline
Campfire Kahuna
Offline
Campfire Kahuna
S
Joined: May 2003
Posts: 15,008

Make sure you know how to adjust your dies if you decide to bump your shoulders.

The first time you “over bump” ... and get around 10 thousands to far - you will get light prime strikes ... click with no bang = no joy.

You won’t forget doing it wrong though...

Re: Partial Full Length Sizing/Bumping the shoulder [Re: mathman] #15240395 09/20/20
Joined: Sep 2006
Posts: 2,185
fremont Offline
Campfire Ranger
Offline
Campfire Ranger
Joined: Sep 2006
Posts: 2,185
Originally Posted by mathman
Originally Posted by Dave_in_WV
Smoke a case neck and with the die set out so the die doesn't contact the shell holder start screwing the die in until the soot is wiped off the neck just at the neck shoulder junction and lock the ring there.


That method can lead to hard chambering.
Seems to me that anyone fiddling around to this extent is kinda looking for hard chambering.


Murphy was a grunt.
Re: Partial Full Length Sizing/Bumping the shoulder [Re: Spotshooter] #15240439 09/20/20
Joined: Sep 2006
Posts: 1,576
D
DonFischer Offline
Campfire Ranger
Offline
Campfire Ranger
D
Joined: Sep 2006
Posts: 1,576
Originally Posted by Spotshooter

Make sure you know how to adjust your dies if you decide to bump your shoulders.

The first time you “over bump” ... and get around 10 thousands to far - you will get light prime strikes ... click with no bang = no joy.

You won’t forget doing it wrong though...


Not sure I understand this. Bump the shoulder to far and get light primer strike's? You can only bump the shoulder so far and you return the case to SAMMI min spec! You get light primer strike's there and I'd guess your chamber has excessive head space. Then either get it fixed or learn to size the case to fit your chamber. That get's back to partial sizing, aka bumping the shoulder.

Re: Partial Full Length Sizing/Bumping the shoulder [Re: DonFischer] #15240760 09/20/20
Joined: May 2003
Posts: 15,008
S
Spotshooter Offline
Campfire Kahuna
Offline
Campfire Kahuna
S
Joined: May 2003
Posts: 15,008

If you are using a redding body die you can compress the shoulder below SAAMI, then the short cartridge will move forward when the trigger is pulled, and you get what seems like light primer strikes, but it’s really you have too much headspace and the brass is moving forward.

I’ve seen brass 10 thousands too short cause this personally.



Originally Posted by DonFischer
Originally Posted by Spotshooter

Make sure you know how to adjust your dies if you decide to bump your shoulders.

The first time you “over bump” ... and get around 10 thousands to far - you will get light prime strikes ... click with no bang = no joy.

You won’t forget doing it wrong though...


Not sure I understand this. Bump the shoulder to far and get light primer strike's? You can only bump the shoulder so far and you return the case to SAMMI min spec! You get light primer strike's there and I'd guess your chamber has excessive head space. Then either get it fixed or learn to size the case to fit your chamber. That get's back to partial sizing, aka bumping the shoulder.

Re: Partial Full Length Sizing/Bumping the shoulder [Re: 300Winnie] #15241094 09/20/20
Joined: Jan 2005
Posts: 10,210
Sakoluvr Offline
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Jan 2005
Posts: 10,210
I use a Wilson adjustable headspace gauge for my belted cases. No measurements are needed.

Take a 1x fired case (or a 2x fired case if it still chambers easily after neck sizing only) and drop it into the gauge and adjust it so it fits. The case will be headspaced on the shoulder. Tighten up the adjustment screw.

Now you have a template of your chamber (Close enough because of spring back).

Adjust your body die by testing brass fit in the Wilson gauge that you adjusted so the brass headspace on the shoulder.

I NK size then FL size in that order. I anneal after 3 firings. Belted brass will last as non belted this way.


Faith and love of others knows no mileage nor bounds. That's simply the way it is.
dogzapper

After the game is over, the king and the pawn go into the same box.
Italian Proverb


Moderated by  RickBin, SYSOP 

RR1
Who's Online Now
139 registered members (10gaugemag, 007FJ, 30Gibbs, 1911a1, 204guy, 17 invisible), 1,221 guests, and 777 spiders.
Key: Admin, Global Mod, Mod
RR2/3










Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2020 24hourcampfire.com, Inc. All Rights Reserved.
 
Powered by UBB.threads™ PHP Forum Software 7.7.3
(Release build 20190728)
PHP: 7.3.23 Page Time: 0.034s Queries: 14 (0.003s) Memory: 0.8623 MB (Peak: 1.0084 MB) Data Comp: Zlib Server Time: 2020-10-26 07:28:13 UTC
Valid HTML 5 and Valid CSS