Need help - Brass is growing during resize.

[Leaddog]

I am using a Redding Type S bushing die (full sizer)with once fired Lapua .308 brass in a Rockchucker press.

I was trying to adjust my die to just bump the shoulder back .002 during the resize operation. When I measure my brass with a Redding precision mic before and after resizing, it shows my brass is growing .002-.003. I have plenty of lube on the cases and they are not sticking.

What do I have to do to get where I need to be? Thanks.

 

[The Mechanic]

Re: Need help - Brass is growing during resize.

That is normal it will grow until you get to the shoulder and start moving that. That is how you know you reached the shoulder when it stops growing. and fill out your profile

 

[Leaddog]

Re: Need help - Brass is growing during resize.

Mech- Then you are suggesting that I screw down my resizing die until I start pushing the shoulder back?

I have a fairly visible ring on the outside of the brass at the base of the shoulder now from resizing. Was this "squeezing" or resizing of the brass that caused my brass, as measured in the mic, to increase for now?

Thanks for your response.

 

[nesikabay]

Re: Need help - Brass is growing during resize.

All brass gets longer. Thats why we buy and use case trimmers. If your going to reload YOU HAVE TO TRIM YOUR BRASS. There is no way around it.

 

[Leaddog]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nesikabay</div><div class="ubbcode-body">All brass gets longer. Thats why we buy and use case trimmers. If your going to reload YOU HAVE TO TRIM YOUR BRASS. There is no way around it.</div></div>

Then how can you accurately determine the shoulder setback on resizing? I have a case trimmer.

 

[nesikabay]

Re: Need help - Brass is growing during resize.

I had my gunsmith make me a tool using the same reamer he did on my barrel. Measure a fired round then measure a fired round. Another way to do is find a piece of brass that chambers hard then size it a little at a time. When you size it enough to where it is where you want it just lock your die down. That will work until your brass get work hardened. Then you have to soften it up.Its hard to cover everything by typing if you want send me a PM and ill give you my number. It would be easter to explain on the phone if you want

 

[Pete E]

Re: Need help - Brass is growing during resize.

Leaddog,

Colour the neck and shoulder of the brass with permanent marker pen before you resize. Once the case has been resized, scuff marks in the ink will show you exactly whats going on and you can adjust the die accordingly...Ideally you want to resize the case such that there is a slight resistance when you chamber it, "slight" being the operative word..

Regards,

Peter

 

[JLM]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Leaddog</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nesikabay</div><div class="ubbcode-body">All brass gets longer. Thats why we buy and use case trimmers. If your going to reload YOU HAVE TO TRIM YOUR BRASS. There is no way around it.</div></div>

Then how can you accurately determine the shoulder setback on resizing? I have a case trimmer. </div></div>

It sounds like you have an RCBS Precision Mic, no? Measure it with that.

 

[The Mechanic]

Re: Need help - Brass is growing during resize.

Now you might ask, how should you set up the sizing die. I forget............. No this is easy just take a fired case and put it in the shell holder then raise the ram all the way up. Now with the depriming rod removed screw the sizing die down by hand until it stops. Lower the ram and remove the case. Using a sharpie/Dychem/layout blue, blacken the case neck and then lube the case lightly. Now , and this is very important, screw down the die about a 3/8” then resize the case. Look at the case neck you should see a shiny section on the top portion of the neck. Continue to resize the case, screwing the die in a little at a time, until the neck is sized almost to the shoulder, take your time so you don’t size or “bump” the shoulder. At this point your die is set to neck size only and for most bolt actions this should do it. To check remove the firing pin from your bolt and carefully chamber the case. The bolt should close with little resistance. If it is tight turn the die in an 1/8 of a turn and size another case then chamber test it, repeat until the case chambers with light resistance when lowering the bolt. This process works best if the brass was fired from the same gun but will work with any brass that is in good shape. Once you get your die set, lock the locking ring tight and place a witness mark on the die and press so the setup can be repeated. If this dozen’t work the sizing die is not a match for your chamber.

 

[ReaperDriver]

Re: Need help - Brass is growing during resize.

I feel stupid for asking, but if I'm only neck sizing.... is my brass actually growing? Or will it fireform to the chamber each time and stay roughly at that dimension?

If if it growing in lenght, what's causing it if I'm not FL resizing the case and moving the brass around?

 

[MitchAlsup]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I feel stupid for asking, but if I'm only neck sizing.... is my brass actually growing? </div></div>

Any time you take a round piece of brass and make it take on a smaller diameter; it gets longer. This is just Murphy's law as applied ot reloading. If the sized round brass got shorter, then the brass would become stronger over its life; because the only way for it to get shorter would be for the wall thickness to increase.

This is true for the neck, the sholder, and the body--depending on which is being sized.

 

[dmgreene]

Re: Need help - Brass is growing during resize.

Leaddog have you tried chambering the brass after you have resized it?. Make sure that the brass will not chamber easily before you start trying to bump the shoulder back. Sometimes it will take up to 3 firings before you start getting any resistance closing the bolt. A lot of it depends on how hot you are loading and the lot of brass you are using.

 

[427Cobra]

Re: Need help - Brass is growing during resize.

Brass gets longer during fl sizing before bumping can begin, scew the die down some more and recheck.

 

[AJ300MAG]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">If if it growing in lenght, what's causing it if I'm not FL resizing the case and moving the brass around?</div></div>

Pressuer is a little high. Are you running loads close to the max charge?

 

[918v]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I feel stupid for asking, but if I'm only neck sizing.... is my brass actually growing? Or will it fireform to the chamber each time and stay roughly at that dimension?

If if it growing in lenght, what's causing it if I'm not FL resizing the case and moving the brass around? </div></div>

Geometry.

If you expand a cylinder it will shorten. If you shrink a cylinder, it will elongate.

Redding sizing dies reduce the diameter of the case at the base and at the shoulder, so even if you are not bumping the shoulder the case elongates and the shoulder moves forward.

I suggest you invest in a Redding competition shellholder set. It allows you to bump the shoulder in precise .002" increments and makes sizing super easy.

 

[ReaperDriver]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I feel stupid for asking, but if I'm only neck sizing.... is my brass actually growing? Or will it fireform to the chamber each time and stay roughly at that dimension?

If if it growing in lenght, what's causing it if I'm not FL resizing the case and moving the brass around? </div></div>

Geometry.

If you expand a cylinder it will shorten. If you shrink a cylinder, it will elongate.

Redding sizing dies reduce the diameter of the case at the base and at the shoulder, so even if you are not bumping the shoulder the case elongates and the shoulder moves forward.

I suggest you invest in a Redding competition shellholder set. It allows you to bump the shoulder in precise .002" increments and makes sizing super easy. </div></div>

I have the Redding Comp dies, but I'm only resizing the neck. So the shoulder and base are not being touched.

never mind, I understand the process of what's happening now.... Thanks

 

[918v]

Re: Need help - Brass is growing during resize.

If you have the Competition FL die, the one with bushings, it still sizez the base and the shoulder area even if you are not bumping the shoulder. If you have the Comp Neck Die, then it should not move the shoulder at all.

 

[ReaperDriver]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">If you have the Competition FL die, the one with bushings, it still sizez the base and the shoulder area even if you are not bumping the shoulder. If you have the Comp Neck Die, then it should not move the shoulder at all. </div></div>

Comp neck die with a seperate body sizing die that I haven't used yet.

 

[918v]

Re: Need help - Brass is growing during resize.

and it's moving the shoulder forward???

I don't think so.

 

[JLM]

Re: Need help - Brass is growing during resize.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I feel stupid for asking, but if I'm only neck sizing.... is my brass actually growing? Or will it fireform to the chamber each time and stay roughly at that dimension?

If if it growing in lenght, what's causing it if I'm not FL resizing the case and moving the brass around? </div></div>

Yes, it blows out to fit the chamber. Then it springs back a little bit so its slightly smaller than the chamber. However the more times you fire your NS brass, the less it springs back so eventually you get to the point where it won't chamber without having to crush it in there when you close the bolt.

At this point you need to bump the shoulder back.

I see the 'neck sizing mafia' run into this problem at the Range a lot. Cases stuck in the chamber and you can't even beat the bolt open with a hammer

 

[The Mechanic]

Re: Need help - Brass is growing during resize.

Don't forget to trim to length after any sizing until you get an idea how much YOUR brass from YOUR rifle expands. At that point you can figure out how often trimming will be needed. Get out that caliper.

 

[Mag 300]

Re: Need help - Brass is growing during resize.

Do you have the answers that you needed?
Bill

 

[Clark]

Re: Need help - Brass is growing during resize.

I did some experiments with dies moving the shoulder back .004".
The rifle has .003" of headspace and I was moving the shoulder back to .001" less than max SAAMI specs for a cartridge.

At 66kpsi .223:
1) The full length Redding "S" die caused the brass to grow .0020" per firing / resizing cycle.
2) The Forster full length with neck honed die caused the brass to grow .0020" per firing / resizing cycle.
3) The Lee collet neck die cause the brass to grow .0005" per firing / resizing cycle.

The Lee Collet produced more concentric ammo than the Forster. The Forster produced more concentric ammo than the Redding, but the differences were so tiny, the effect could never be measured at an outdoor range.

 

[KYpatriot]

Re: Need help - Brass is growing during resize.

My search-fu is poor but there was another thread about this in which someone suggested taking a fired 40SW case and placing it over the mouth of the .308 case- the mouth of the 40 case will index on the shoulder of the 308. You could then measure with calipers the overall length of two cases together, then resize the 308 case, put the 40on there again and measure again. The difference in the two meaurements is how much you are bumping the shoulder. I tried it and seemed to work fine.