223 Lapua Brass Sizing Issue

[RackOpsTactical]

Hey guys, been loading for a while and not had this issue. i'm getting these ridges or rings at the base of the case after resizing. the ring is making it to the point that it will not fit into a case gauge. it's catching on the ridge or lip being created. i've not had this issue with Norma brass but am now getting it on Laupa brass. i'm using the same position of my resize die that i did with the Norma.

I have also tried backing off the die as far back as I can without getting out of spec and i'm still getting it.

any ideas or help would be great.

 

[Milo 2.5]

First, are you using a smallbase die or a reg die to size with?
I think what you are seeing is a difference in hardness or thickness of brass in that area with the Lapua. You are basically rolling brass on the Lapua.
First thing you need to do is measure fired brass in that area and sized brass to see how much you are constricting it.

The problem itself could range from your sizing die being a little tight, to a grossly oversize chamber, so give us some numbers and we will go from there.

 

[bax]

I can't tell from the pictures, is brass being scraped off the case body and piling up above the extractor groove or is the case body being squeezed smaller than the rim?

Go to the SAAMI site, download the 223 drawing, and get out your trusty dial/digital caliper :

(a) using the chamber drawing, check a fired case - especially just above the extractor groove, it should be chamber-sized not more than .001 larger than spec or .002 smaller than spec. The goal here is to verify that the chamber is for .223 or 5.56 ammo.

(b) using the case drawing, after FL sizing, check the brass above and below this belt you are making. The idea is to verify that your die is the right size.

If the case body is squeezed smaller, suspect your die. If the fired brass is significantly larger than chamber spec, suspect your chamber.

For what it's worth, you might try sizing with a lot of lube. Sizing 223 with proper lube should require relatively little force.

 

[steve123]

I had this problem once with another cartridge. Fortunately I have a small lathe! I wrapped some fine sandpaper on a pencil, working down from 180 grit to 600, and polished the inside of the die. It took a little over .001" off but was a high polish inside.

I also bought imperial die wax.

Problem solved.

 

[RackOpsTactical]

thanks for the replies. I'm concluding that the brass on Lapua is just softer. i know i don't have a problem with my chamber as i have mic'ed fired cases. My die is a small base 223 RCBS with a polished expander ball. I use a sinclair mandrel to set the neck tension. i am planning to switch to a forester sizing die in a few weeks. thinking the unneeded small base may be the issue. even though never had this happen with any other brand of brass, all else being equal.

what i ended up having to do was put my drill in a vise, chuck up a mandrel, and use 800 grit sand paper to just take about 2 thousands off the small lip. (see pic)

has anyone seen this with their Lapua brass?

 

[bax]

thanks for the replies. I'm concluding that the brass on Lapua is just softer. i know i don't have a problem with my chamber as i have mic'ed fired cases. My die is a small base 223 RCBS with a polished expander ball. I use a sinclair mandrel to set the neck tension. i am planning to switch to a forester sizing die in a few weeks. thinking the unneeded small base may be the issue. even though never had this happen with any other brand of brass, all else being equal.

what i ended up having to do was put my drill in a vise, chuck up a mandrel, and use 800 grit sand paper to just take about 2 thousands off the small lip. (see pic)

has anyone seen this with their Lapua brass?

Not me. But I don't use a small base die so different circumstances.