Bumping the shoulder with RCBS dies

[barefooter56]

PowellSix0,
Mikecr has the right idea. Not all brass "grows" at the same rate when fired. So follow Mikes suggestion. Problem with neck sizing going along until you need to bump the shoulder back is that the brass becomes fire hardened and since brass likes to spring back you will need to bump the shoulder back farther to compensate for spring back and the brass being somewhat hardened. This works the brass even more and shortens its life. You can anneal to help this issue if you wish. Setting up your full length or body die to bump the shoulder back .001-.003 and sizing it every time ( .001-.002 target, .002-.003 hunting) does not work the brass as much as if you had set the die up per the manufacturers instructions. This helps the brass life and also enables you to load rounds that will chamber every time. Benchrest shooters are going to this so they don't have to worry about a round not chambering during a "run" so they can shoot a condition. The other upside is that they are reporting better brass life too. Another die to consider is the Forster BUMP die. It only does the shoulder and not the case body. And you can use it with or without the neck sizing bushing. The REDDING Competition Shell holders CAN make getting your shoulder bump set up easier. Instead of adjusting the die to get the bump you want. Set the full length, body, or bump die up touching the shell holder with the ram raised to its full stroke using a standard Redding shell holder. Measure your brass with a bump gauge and start with the .010 thick Competition shell holder and work down until you get the bump you want. The above will only work on brass fired in your rifle. Range brass or co-mingled brass is a whole nother can of worms. Hope this helps!
Take care,
Phil Hoham
Berger Bullet Tech

 

[Dr. Vette]

this is directly from reddings site "Body dies are designed to full length size the case body and bump the shoulder position for proper chambering".

Isnt this the same as my RCBS full length sizer die except my RCBS die also deprimes and neck sizes as well...so why not simply when the cases start sticking, then instead of neck sizing them the next time I reload them I full length size with my rcbs die but only bump the shoulder back .001-.002

It's the same, but it's not the same. The biggest difference is how the necks are sized. My usual neck sizing involves either the Redding bushing die or the Lee collet die. Each of these works the necks far, far less than your usual full sizing die. If you want to check, remove the expander ball from your current die and run a case through. Measure the neck and see how small it is compared to when it is loaded and you'll see what I mean. The collet die and the bushing dies move it only as much as needed.

There are a couple of calibers I reload that do not have one of the aforementioned dies, but not for long.

 

[PowellSixO]

Thank you very much for that information.

So another scenario I'm thinking about here.................

Let's say I start over with all new brass. I load the new brass, and fire form it in my rifle. Can I then take my Hornady Headspace Gauge Measurement tool and measure from the shoulder of the case to the base of the case, and then record this measurement, and treat it kind of like my COAL (measuring with my Hornandy Bullet Comparator measurement tool / ogive of the bullet to the base of the case)? So similar to loading my bullets to a specific seating depth to achieve my specific COAL, I do the same thing with the FL die, and I just push the shoulder back to match the measurement I recorded from the fire formed brass if or when it needs it? I hope that makes sense.

PowellSix0,
Mikecr has the right idea. Not all brass "grows" at the same rate when fired. So follow Mikes suggestion. Problem with neck sizing going along until you need to bump the shoulder back is that the brass becomes fire hardened and since brass likes to spring back you will need to bump the shoulder back farther to compensate for spring back and the brass being somewhat hardened. This works the brass even more and shortens its life. You can anneal to help this issue if you wish. Setting up your full length or body die to bump the shoulder back .001-.003 and sizing it every time ( .001-.002 target, .002-.003 hunting) does not work the brass as much as if you had set the die up per the manufacturers instructions. This helps the brass life and also enables you to load rounds that will chamber every time. Benchrest shooters are going to this so they don't have to worry about a round not chambering during a "run" so they can shoot a condition. The other upside is that they are reporting better brass life too. Another die to consider is the Forster BUMP die. It only does the shoulder and not the case body. And you can use it with or without the neck sizing bushing. The REDDING Competition Shell holders CAN make getting your shoulder bump set up easier. Instead of adjusting the die to get the bump you want. Set the full length, body, or bump die up touching the shell holder with the ram raised to its full stroke using a standard Redding shell holder. Measure your brass with a bump gauge and start with the .010 thick Competition shell holder and work down until you get the bump you want. The above will only work on brass fired in your rifle. Range brass or co-mingled brass is a whole nother can of worms. Hope this helps!
Take care,
Phil Hoham
Berger Bullet Tech

 

[Mikecr]

There is a big misnomer about die types out there; 'FL bushing die' is one of them. There are only a handful of custom dies that utilized a bushing which includes shoulder. By far most bushing dies use the Wilson type sizing bushings. These partial neck size.
Actual FL dies FL size the necks. Normal bushing dies, whether called neck sizing or FL sizing do not.
A standard RCBS FL die would FL size the necks by the time it's set to FL size the bodies, and there is nothing good in doing this. Truly, it's a disaster.

Some folks use bushing neck dies to an extra benefit; adjusting length of sizing. This is ACTUALLY how you control tension.
I separate body sizing and neck sizing, by using Redding body dies and Wilson neck sizing dies. But it's not required, there are plenty of good FL bushing dies that allow separate adjustment.

But my body dies are customized so that they only shoulder bump, similar to the Forester bump die mentioned. I have them fitted to fired brass by JLC Precision.
JLC also provides custom body-bushing dies, which are fitted Redding body dies that include adjustable bushing neck sizing. Nice dies, I have a couple, but I still use Wilson instead for my bushing neck sizing. Just like em..

Which goes full circle: a normal 'FL bushing die' is not,, it's actually a 'body-bushing die' with actions separately adjustable.

You can have custom FL dies made(actual FL). There is nothing wrong with this approach, but avoid FL sizing of necks. You don't want to bring in, and amplify, donut action to your results.

 

[barefooter56]

Thank you very much for that information.

So another scenario I'm thinking about here.................

Let's say I start over with all new brass. I load the new brass, and fire form it in my rifle. Can I then take my Hornady Headspace Gauge Measurement tool and measure from the shoulder of the case to the base of the case, and then record this measurement, and treat it kind of like my COAL (measuring with my Hornandy Bullet Comparator measurement tool / ogive of the bullet to the base of the case)? So similar to loading my bullets to a specific seating depth to achieve my specific COAL, I do the same thing with the FL die, and I just push the shoulder back to match the measurement I recorded from the fire formed brass if or when it needs it? I hope that makes sense.

PowellSix,
Go back to Mikecr post on firing a piece(s) of brass until they start to chamber hard and use those to set up your die. Once fired brass may not be full "blown out" to your chamber yet. Measure the fired brass that chambers hard before you run it through the die so you have a baseline . Then adjust the die to bump the should back how you want. Put that measurement in your load book as a reference like your COAL. Test the brass in your rifle for resistance as you adjust the die or change Competition shell holder thickness. IF you can get the firing pin assembly out of the bolt you will have a better "feel" of the resistance as you test. 3/4ths of the throw should have no resistance . Last 1/4 should feel like a knife going through butter. Mikecrs mention of having a custom die made may be a good thing to think about. With one of those you could control the shoulder bump and the body sizing for your existing chamber. A good gunsmith can do that for you. Newlon dies makes blanks. If you plan on using the die a lot you may want to get it heat treated after its done to your satisfaction.
Take care,
Phil Hoham
Berger Bullet Tech