How to measure for and set up FLR shoulder bump?

[DartonJager]

For years and years, EVERYTHING I have ever read or seen in video claims when you full length resize your fired brass for use in a standard non custom cut chamber your goal is to bump the shoulder of the case back between 0.002"-0.003".

Great, how does one measure your fired brass prior to sizing then how do you set up your FL sizing die to limit the bump to 0.003" or less? I am concerned about bumping the shoulder to far back and the problems associated with doing so.

I did a Google search and ended up much more confused than informed by all the conflicting methods that claimed to be the best most accurate way to do this. I grasp the removing the firing pin from my bolt guns, but not sure if it will work for my lever guns.

So please those who know what is a good way to do this for standard factory rifles, please educate me.

Thanks,
DJ/Art.

 

[FURMAN]

The best way is to get the correct gauge. Hornady makes a nice set. You simply measure the fired brass and "bump" the shoulder around .002". With most dies you will back the die off the shell holder a turn and slowly turn the die in while sizing and checking the brass until the desired "bump" is achieved. In some instances you may need something like the Redding competition shell holder set. In any case the Redding kit will most likely make it easier to repeat if you swap dies a lot.

 

[243winxb]

all the conflicting methods that claimed to be the best most accurate way to do this.

You will get the same info here,sorry to say.

Learn to use a Hornady Comparator.

 

[cape cove]

Check the thread on- need help with pressure problems- post # 15 pictures 2 and 3.Should help some.

 

[FURMAN]

 

[DartonJager]

Thanks for the replies so far. I need to remind myself every now and then what reloading tools I have. I own and often use a Stony Point comparator and thought I also bought a S/P head space gauge set, went and looked through my reloading stores and sure enough there they were the complete set of gauges.
But the directions on how to use them were missing.
So am I correct I first take a fired case use the proper sized gauge and measure it, deduct 0.002" then set up my FL sizing die and size , measure and repeat till I size the brass 0.002" less than the fired case?

Strange how the more I organize my reloading tools and components into small separate Tupperware containers the more often I forget what tools and components I own.

 

[FURMAN]

Yes.

 

[Rick Richard]

Yep

 

[DartonJager]

Thank you, and all others who replied. I have one last question. In all my reloading manuals there is a mechanical drawing of every case showing it's dimensions. Am I correct in assuming the measurement listed as the case's head space is the SAMMI maximum same as the length that is also listed?

 

[Timeout]

For years and years, EVERYTHING I have ever read or seen in video claims when you full length resize your fired brass for use in a standard non custom cut chamber your goal is to bump the shoulder of the case back between 0.002"-0.003".

Great, how does one measure your fired brass prior to sizing then how do you set up your FL sizing die to limit the bump to 0.003" or less? I am concerned about bumping the shoulder to far back and the problems associated with doing so.

I did a Google search and ended up much more confused than informed by all the conflicting methods that claimed to be the best most accurate way to do this. I grasp the removing the firing pin from my bolt guns, but not sure if it will work for my lever guns.

So please those who know what is a good way to do this for standard factory rifles, please educate me.

Thanks,
DJ/Art.

You don't need to buy the whole Hornady setup to measure your cartridge case for measuring to bump. These https://www.brownells.com/reloading...tors/sinclair-bump-gage-insert-prod35265.aspx are all you need. Simply put it on the case shoulder and measure direct with your calipers. Back off your die and work in a little at a time until you have the desired bump. Hornady die locking rings work great for making the adjustment process easy. https://www.brownells.com/reloading...ment-parts-upgrades/lock-rings-prod32669.aspx On sale right now. Regardless the brand die I use, they all are equipped with Hornady locking rings. Another thing to keep in mind is brass does not always fully form to it's maximum length in one firing. Load and fire one case 3 times without bumping and take your "fired" measurement from that one. I bump .001"-.002" for bolt action rifles.

 

[243winxb]

In all my reloading manuals there is a mechanical drawing of every case showing it's dimensions. Am I correct in assuming the measurement listed as the case's head space is the SAMMI maximum same as the length that is also listed?

Find cartridge and chamber drawings here. http://www.saami.org/specifications_and_information/index.cfm

Note the tolerance difference between cartridge and chamber.

 

[Remmy700]

There are so many tools now to help with this. For years I would back my die out and resize mainly just part of the neck and body ensuring I was not touching the shoulder until how ever many firings it took to make that round not be able to chamber. Once I reached that point I would then keep screwing my die in a little at a time until I feel it touch the shoulder and would chamber that round and by feel of bolt closure firmness set that die up. Maybe just unexperienced but it worked very well. I have since bought the hornady headspace gauges so I can visually see the numbers but my process still has not changed much. No matter what you do there are going to be some calibers that you are going to have to fire multiple time especially with new brass until it actually grows to the correct dimension of the chamber. Many people will once fire brass and then set their dies up based on those dimensions but more times than not that brass has now grown enough to actually be truly chamber fire formed.

 

[stx]

There are so many tools now to help with this. For years I would back my die out and resize mainly just part of the neck and body ensuring I was not touching the shoulder until how ever many firings it took to make that round not be able to chamber. Once I reached that point I would then keep screwing my die in a little at a time until I feel it touch the shoulder and would chamber that round and by feel of bolt closure firmness set that die up. Maybe just unexperienced but it worked very well. I have since bought the hornady headspace gauges so I can visually see the numbers but my process still has not changed much. No matter what you do there are going to be some calibers that you are going to have to fire multiple time especially with new brass until it actually grows to the correct dimension of the chamber. Many people will once fire brass and then set their dies up based on those dimensions but more times than not that brass has now grown enough to actually be truly chamber fire formed.

Yep...thats how we used to do it, as well.

 

[DartonJager]

Thanks to all for the help. I am printing it out and using it to prep my brass.

Thanks again to all,
DJ/Art