partial re-sizing and case length

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gone fishing

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Hi,

I have just started reloading, and am at the stage of resizing all of my .308 Win. brass with an RCBS rock chucker, single stage press.

I have been trying to only partially re-size the cases as described in my Nosler reloading manual. Holding the Hornady die 1/16" off of the shell holder at the top of the stroke.

My problem is that the cases go in at an acceptabe length and come out about 1/200" longer. These Remington cases have only been fired once.

Full-length re-sized cases are coming out the same way. When I have the shell holder come up to touch the die.

I wonder if I could be doing something wrong. I am worried that if I fire these cases which are now 2.020" as opposed to the max case length of 2.015" they will result in a pressure spike.

From what I have read I should not have to start trimming on the first re-load.

Might anyonehavesome advice on setting up my full length die for a partial resizing?

Its an RCBS rock chucker press with hornady dies.

Thank you in advance to anyone who might be able to shed some light.
 
Size them the way you want to, making sure they will go into your rifle's chamber.
If the cases are then over length, trim them. It doesn't matter if it is first reloading, or tenth, if too long, trim.
As you appear to know, necks that are too long can pinch the bullet, preventing its release, thus raising pressure, sometimes a lot of extra pressure.
There is little, or no problem if the cases are a bit shorter than specs.
 
I tried partial sizing as a sort of poor man's neck sizing, and I found partial resizing lengthened cases more than full length resizing, so I switched to honest neck sizing dies that do not squeeze the case at all. They seem to grow much more slowly now.
 
rral22 said:
I tried partial sizing as a sort of poor man's neck sizing, and I found partial resizing lengthened cases more than full length resizing, so I switched to honest neck sizing dies that do not squeeze the case at all. They seem to grow much more slowly now.
Click to expand...

Could be. A 308 is not known as one that grows the brass fast. the 30-06 is also slow, but the 270 is much faster and a 243 is the fastest growing of any of the standard calibres I have used.
 
Are you lubricating the inside of the neck before sizing? I use a nylon bore brush dipped in powdered graphite (from Canuck Tire), to lube the ID. One issue with standard FL and even neck dies is that they size the neck down too much and then have to open them back up a lot with the expander ball. In doing that you may be stretching the case, especially with no ID lube. Worse still you may be making the case neck eccentric from the body.

That is the advantage of a bushing die. They size the neck down just the right amount so an expander ball is not needed or does very little.
 
Sometimes that happens, sometimes they're well short of the max trim length and sometimes they're right up against it. Just trim them. The cost of using up brass is far less than the cost of a damaged rifle due to a pressure-related incident.

Neck sizing will increase your case life substantially. If keeping a close eye on your costs, buy a neck sizer for $30-40 and make that money back on the first bag of brass.
 
Thanks,

This feedback is great, and right on.

I did lubethe necks with standard RCBS case lube and a nylon brush, but there is obvious stretching where the neck meets the shoulder. I think you were right on Ron AKA in saying that the expander ball is having to do a lot of work. There was a lot of pressure on the press arm while raising it back up.

I'll try the graphite and start looking for a neck die.

Thanks everyone.
 
gone fishing said:
I'll try the graphite and start looking for a neck die.
Click to expand...

I would look at the Lee Collet Die. It is one of the very best dies for neck sizing only. You can read about it on the Lee site, and here is a testimonial. A lot of serious loaders use them to get outstanding accuracy. It uses no expander ball. I don't have one as they don't make them in 6BR, so I bought a Forster Bushing/Bump die. That is also another choice for you, but will cost quite a bit more than the Lee.

Lee Collet Die Testimonial
 
I'm using a lee collet neck sizing die, and it's great. I did have to polish the mandrel down a bit to get good neck tension though. I'd suggest measuring it and verifying your neck id's. My first batch was quite loose.
 
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