case length
- Thread starter rkr
- Start date
I believe and not 100% sure,
That brass flows.
Brass casing is too fat and getting shrunk in a resizing die,
That extra brass doesn’t disappear, it flows upwards towards the neck,
I trim every firing, and always trim after resizing
That brass flows.
Brass casing is too fat and getting shrunk in a resizing die,
That extra brass doesn’t disappear, it flows upwards towards the neck,
I trim every firing, and always trim after resizing
Brass flows forward each time it’s fired. Each time you size brass you need to check that the case is below the max case length. If it meets or exceeds the max spec it has to be trimmed back to the min length.
You can’t only neck size because eventually the shoulder will move forward and it will be difficult if not impossible to chamber a round. This is when you need to do a FL resize to push the shoulder back.
You can’t only neck size because eventually the shoulder will move forward and it will be difficult if not impossible to chamber a round. This is when you need to do a FL resize to push the shoulder back.
A picture is worth a thousand words and the illustration below tells the story.
If you lube the insides of the case neck and polish your expander it will not create excessive drag and pull the shoulder forward.
Below a new RCBS expander that needs polishing, no wonder a expander pulls on the case neck.
Below on my Redding FL .243 die I replaced the "LONG" Redding expander with a Forster high mounted floating expander. The Forster expander reduces drag and greatly reduces neck runout. Too many people think using a expander is the end of the world and all it takes is a little polishing and lube. Redding also sells replacement carbide expander balls with less drag.
Below you can remove the expander from any die and use a expander die that pushes "down" on the case neck.
Below a very good dry inside neck lube.
If you lube the insides of the case neck and polish your expander it will not create excessive drag and pull the shoulder forward.
Below a new RCBS expander that needs polishing, no wonder a expander pulls on the case neck.
Below on my Redding FL .243 die I replaced the "LONG" Redding expander with a Forster high mounted floating expander. The Forster expander reduces drag and greatly reduces neck runout. Too many people think using a expander is the end of the world and all it takes is a little polishing and lube. Redding also sells replacement carbide expander balls with less drag.
Below you can remove the expander from any die and use a expander die that pushes "down" on the case neck.
Below a very good dry inside neck lube.
You can also have Forster hone the neck of their dies to your desired diameter that way expander will glide through the neck like snot on a door knob.
And at the Whidden custom die website they sell expander kits with five expanders. The expanders are from bullet diameter to .004 under bullet diameter.
The trick is to know your case neck thickness and how much your die reduces the neck diameter and work from there.
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Also, annealing I've noticed helps with how much growth you get with a sizing pass as well. I find full-length sizing has the added benefit of feeding reliability. Everyone will have a different thought on this, but it's what works for me. I tried neck sizing, and it didn't perform like I thought it would. I found that on an initial sizing, I anneal, then size (with lube on the inside of the casing), then I try to the shortest allowable spec and go from there. All these things lead to only about 0.001" per firing and sizing. I hate trimming but had very limited success with neck sizing. Another considerable factor is brass quality. I had some Remington 223 brass that grew .005" on a single sizing, I was shocked! But that was before my annealer came. I wonder how it would go now.
I'm not 100% sure why it does it or what causes it but I know it happens, I figure it's a combination of all the explanations listed above.
I size all my brass before I measure it.
I full length size every time and trim as needed, I don't turn necks, I don't anneal. I keep it simple and have made plenty of sub moa loads for my rifles.
If I was a competitive shooter I would probably do more case prep but for my shooting, spending a few more hours prepping brass just isn't worth it chasing after a 1/8 MOA improvement.
As buji88 says, full length sizing improves feeding reliability and if you're loading for a semi auto it becomes mandatory to FL size.
I size all my brass before I measure it.
I full length size every time and trim as needed, I don't turn necks, I don't anneal. I keep it simple and have made plenty of sub moa loads for my rifles.
If I was a competitive shooter I would probably do more case prep but for my shooting, spending a few more hours prepping brass just isn't worth it chasing after a 1/8 MOA improvement.
As buji88 says, full length sizing improves feeding reliability and if you're loading for a semi auto it becomes mandatory to FL size.
