Shoulder Bump

[reloader22]

So for years, I have full length resized for my .243, 7mm Mag, .223 and 30-30.  I am not a bench rest shooter, mostly a deer hunter.  I have always struck good accuracy and long brass life in general.  However, my 7mm is a different animal.  1/2 my full length resized brass are very tight to where I can barely close the bolt.  I did a bunch of research on this and it seems that when you make the bottom of the die touch the shell holder, you will bump the shoulder back well more than needed.  Appears that what happens in all my guns except the 7mm.  A buddy gave me some redding custom shell holders that raise or lower the shell in 2/1000th increments.  After calipering each of them and comparing the measurements to my shell holder that comes with my RCBS dies, my shell holder was actually the same size as the most aggressive shell holder.  So basically, I was bottomed out with no room to move the shoulder.  I ordered a Larry Willis gadget that measures the shoulder on a once fired case in your own gun to get a reference.  Then meausre the resized cases I have on hand and determined that my shoulder was .003-004" taller than a fired case.  But I had no way to gain any bump with my dies, my shell holder or the redding competition shell holders.  What I ended up doing was adding a piece of scotch tape to the inside of my shell holder and taking a piece of brass and running it.  COOL, I gained some bump but not enough.  Ended up with three layers of scotch tape and a measured .002" of bump.  All shells feed smoothly.  So my chamber may be slightly "off".  ?.  Either way, I think I have this dealt with.  I was blown away that after 30 years of reloading what I thought was decent ammo, that I did not catch on to this.


I also have a bag of virgin brass and I measured them as well.  They are 24/1000" too short relative to a properly sized, bumped case for my gun.  WOW!.  I guess they want everyone to have a smooth chambering round right off the bat regardless of experience.  After reding this, does anyone have any similar experience where a die set properly for full length resizing will not even get the shoulder back enough to chamber a round nicely?  Has anyone dealt with it like I did?  I felt like I was just using common sense here but maybe I am missing something.  What an interesting day it was.


 

[reloader22]

Also, my gun is an early 1960's Model Rem 700.

[71yella]

I have same issue with wife's 7-08, bolt was very difficult to close on sized cases. Had to mill a fee thousands off bottom of die, problem solved.

[alexcray]

Nov 26, 2021 14:18:27 GMT -5 reloader22 said:

So for years, I have full length resized for my .243, 7mm Mag, .223 and 30-30.  I am not a bench rest shooter, mostly a deer hunter.  I have always struck good accuracy and long brass life in general.  However, my 7mm is a different animal.  1/2 my full length resized brass are very tight to where I can barely close the bolt.  I did a bunch of research on this and it seems that when you make the bottom of the die touch the shell holder, you will bump the shoulder back well more than needed.  Appears that what happens in all my guns except the 7mm.  A buddy gave me some redding custom shell holders that raise or lower the shell in 2/1000th increments.  After calipering each of them and comparing the measurements to my shell holder that comes with my RCBS dies, my shell holder was actually the same size as the most aggressive shell holder.  So basically, I was bottomed out with no room to move the shoulder.  I ordered a Larry Willis gadget that measures the shoulder on a once fired case in your own gun to get a reference.  Then meausre the resized cases I have on hand and determined that my shoulder was .003-004" taller than a fired case.  But I had no way to gain any bump with my dies, my shell holder or the redding competition shell holders.  What I ended up doing was adding a piece of scotch tape to the inside of my shell holder and taking a piece of brass and running it.  COOL, I gained some bump but not enough.  Ended up with three layers of scotch tape and a measured .002" of bump.  All shells feed smoothly.  So my chamber may be slightly "off".  ?.  Either way, I think I have this dealt with.  I was blown away that after 30 years of reloading what I thought was decent ammo, that I did not catch on to this.


I also have a bag of virgin brass and I measured them as well.  They are 24/1000" too short relative to a properly sized, bumped case for my gun.  WOW!.  I guess they want everyone to have a smooth chambering round right off the bat regardless of experience.  After reding this, does anyone have any similar experience where a die set properly for full length resizing will not even get the shoulder back enough to chamber a round nicely?  Has anyone dealt with it like I did?  I felt like I was just using common sense here but maybe I am missing something.  What an interesting day it was.



Interesting experience! Sounds like you did some great detective work to solve your 7mm Rem Mag brass issue. Using the tape shim is a neat trick, though not ideal. Have you considered a body bump die? It would give you more precise control over shoulder setback without messing with the shell holder.