Shoulder bump headspace

FEENIX

Well-Known Member
LRH Team Member
Joined
Dec 20, 2008
Messages
17,647
Location
Great Falls, MT
Hello,
I'm having an issue with shoulder bump/adjusting my headspace & hoping somebody can help. I use redding competition dies (FL sizing die & micrometer seating die) with redding competition shell holders & RCBS shell holder. So I resized my brass & noticed my shoulder bump was not adjusting to the 2 thou under that I'm looking for. I have moved my die to both cam over, to just touching, to off the die slightly. I used every redding shellholder as well as rcbs shellholder & it will not adjust up towards the 2 thou under my fired brass measurement. In fact it only keeps moving it the opposite direction (10-15 thou under my fired brass) I did use the same piece of brass with each shell holder & die adjustment. Could it be that I'm using the same piece of brass? Something I'm doing wrong? Problem with my die? Any help would be appreciated. Thank you.
Try this ...

 

JustMe2

Well-Known Member
Joined
Feb 18, 2012
Messages
280
When adjusting your FL die, always use a different piece of fired brass for each adjustment. Don't use the same piece over and over again, especially if you've already adjusted it too short. Resizing one piece again will not make the shoulder longer once it's too short.

Also resizing the same brass (even if not fired) multiple times will harden your brass and shorten its life.
 
Last edited:

UncleDano

Well-Known Member
Joined
Dec 28, 2016
Messages
71
Location
Salt Lake City, Utah
Maybe it would be less confusing by using the standard shell holder, and make all the adjustment with the FL die, starting with the die backed off 1/2 - 3/4 turn. Check with gauge and make small adjustments till you get there and lock it down.
 

UncleDano

Well-Known Member
Joined
Dec 28, 2016
Messages
71
Location
Salt Lake City, Utah
I'm confused myself :) Using hornady's headspace gauge kit I measured a fired piece of brass which measured 1.7385 using a mititoyo caliper. I then proceeded to size a cleaned piece of brass using reddings competiton shell holder starting with #4 which was giving me 1.7335. I then begin to use #'s 10,8,6,2 each time getting either no change or if it did change the measurement went further out. I then used a RCBS shell holder, and also adjusted the FL sizing die by slightly touching to cam over which I also did with all the redding shell holders as well. If the measurement did change it went further out & now the brass is at 1.7285. So no matter what I attempt I cant get the brass to move closer to the fired brass & 2 thou headspace of 1.7365. I'm obviously doing something wrong or my FL redding die is out of spec? As I stated above this brass has 4-5 reloads on them so the brass has been worked enough IMO? I'm racking my brain so I figured I would post on this forum as I respect the knowledge of the folks that post on here who know far more then I do. I've been reloading for 5 years now so I have alot of learning to go. Thanks for any help you can provide.
Start with the #10, not the #4.
 

sedancowboy

Well-Known Member
LRH Team Member
Joined
Nov 28, 2014
Messages
789
Location
Wilsall, MT
measured 1.7385 using a mititoyo caliper. I then proceeded to size a cleaned piece of brass using reddings competiton shell holder starting with #4 which was giving me 1.7335.
If a +.004 shell holder gave you .005 bump and you wanted .002-.003 bump. You should use a +.006 shell holder and you would be within .001 of you goal. You have to use a different piece of brass for each test. Have you annealed your brass. Once it gets work hardened you are not going to be able to be very precise in bumping shoulders.
 

DUSTY NOGGIN

Well-Known Member
Joined
Mar 18, 2015
Messages
874
Location
salt lake city
are you sure its a FL die ( type s in first picture ). competition sets, have a body die that does the side wall shoulder bumping and a neck bushing die that does the neck only . ( second picture )
. 2 separate operations



does your kit look like this

1633821826545.png


or, like this


1633821927709.png
 
Last edited:

SSgt G Cody

Well-Known Member
Joined
Feb 23, 2020
Messages
131
Location
Asheville, NC
Yes, sounds like your brass is too short already. It only "Grows" by firing it. After a couple more firings, carefully neck size in tiny steps until it can be easily chambered! Stop there! You should be Very Close! Then fine-tune in micro steps, only as needed. Re-check all case measurements to be sure! Remember, headspace is established by the shoulder, Not OAL! Keep OAL .010 under max length!
 
Top