FL Sizing, Necks getting grooved.

'Boo said:
I suspect the marks could a result of very slight irregularites in the brass thickness of the necks during their forming at the factory.

I would try a different brand of brass and see if the markings still appear.
Click to expand...
I've tried Winchester and Remington as well.

Not the rifle. Shooting factory ammo, brass is fine until i run it through the said die. The scratches or grooves take place with new brass that has been prepped.
 
If you have a brass build up, which can happen, you will have to remove it before you polish the neck sizing area of the die.

You're going to need something that will dissolve the brass, such as Sweets, Barnes CR10, or Wipe Out (might not be aggressive enough)

Cartridge case brass is mostly made up of Copper/72%, Zinc/24%, Lead/Zinc/Tin 4%.

The lineal striations on your necks can be caused by a couple of things.

Dirt (carbon), case fouling, lack of lube, too hard.

If you're getting accuracy issues, I'm going to go with too hard case necks, creating a tension issue.

If you're going to use anything to polish the insides of your dies, be extremely careful, polishing compounds are "abrasive," and they will remove steel, so is emery cloth.

If the dies were smooth enough before this happened, don't try fixing them.

Use a Copper solvent, along with a good cleaning brush.

I've had similar issues, and cleaned them with Copper Solvent, stainless steel bristle bore brush, which won't mark the die steel, followed by a a jag wrapped with very fine steel wool, soaked with Copper Solvent, then a good clean up afterwards with boiling water and some light lubricant.

Both copper and carbon can build up to leave such marks.
 
Last edited:
jamesharrison said:
What does your fired brass look like before being sized?

Any chance it's your rifle's chamber?
Click to expand...
This could be a possible cause.

I really don't think it is caused by a build-up within the die, especially as the marks appear using 2 different dies - one of them brand-new.

Is there is an issue within the rifle chamber the case necks may not be expanding symmetrically but you wouldn't necessarily notice the issue until the neck is sized down in a die with the greatest force being generated at the high spots.

I would check out the rifle chamber with a bore scope at the very least.
 
'Boo said:
This could be a possible cause.

I really don't think it is caused by a build-up within the die, especially as the marks appear using 2 different dies - one of them brand-new.

Is there is an issue within the rifle chamber the case necks may not be expanding symmetrically but you wouldn't necessarily notice the issue until the neck is sized down in a die with the greatest force being generated at the high spots.

I would check out the rifle chamber with a bore scope at the very least.
Click to expand...
From the OP's first post, this is an issue that's creeped up on him, and all was well previously.

If it were a chamber issue, such as those caused by reamer chatter, it would have shown up after the first shot.

The marks in the pics show "bright" streaks after sizing, if it were a chamber issue, the striations would be visible "after" shooting.

If they are visible after shooting, which should iron them out of sight, then there is a chamber issue.
 
OK, riddle me this:

He used 2 different sets of dies and the marking on the case necks remained the same.

He used several different brands of cases and the marking on the case necks remained the same.

The only constant in this is the rifle itself.

It doesn't have to be "reamer chatter" as carbon or corrosion buildup would be more likely.
 
Nickel plated brass flecks are likely embedded in the neck of the die, had to polish a couple in the past after sizing nickel plated brass, polished them out with a Dremel and polishing compound.
 
dgradinaru said:
RCBS brand. I had a spare set of new dies, sealed in the box that I opened last night, deburred, chamfered the brass sprayed it with lube and this is the way it came out. I've been reading up on this and a few from other forums have made mention that the die needs to be polished.

PNlorxq.jpg
Click to expand...

I get lines like these on my .223 brass after the die gets dirty. Like 10k cases sized dirty. The solution is to clean the hell out of the dies. The ammo chambers and shoots fine so I don't get to worried about it when it starts happening but this is bulk range plinking ammo with mixed brass. It happens with RCBS, RCBC small base and Dillon dies. For precision rifles I use Redding dies which don't get near the workout so mostly stay pretty clean.
 
Thunderhog said:
Not if the dies are brand new!

What caliber is the rifle and brass?

358 Winchester?
Click to expand...
Op said dies were 10+ years old in the first post. I've had identical marks on case necks only with dies that ive sized nickel plated brass with, even after cleaning, there was tiny nickel flakes still stuck in the neck of the die.
 
300_savage said:
Op said dies were 10+ years old in the first post. I've had identical marks on case necks only with dies that ive sized nickel plated brass with, even after cleaning, there was tiny nickel flakes still stuck in the neck of the die.
Click to expand...
I saw that yes. However he also stated the marks were identical on a brand new set of dies he also tried. :)

So the dirty die theory does not make sense.:oops:
 
I was going to suggest to anneal the necks because maybe the brass is work hardened and maybe causing the issue but the op said he used new brass with the same result so I dunno
 
It's just scratches from junk built up or a slight burr at the shoulder/neck junction inside of the dies. It's common when resizing nickel plated brass from flakes of nickel imbedded in the die but can happen with any brass case from plain ol' dirt. I just remove the decapping stem, chuck a bore brush in an electric drill. wrap the brush with a little fine steel wool, add a few drops of gun oil for lube, and run that in the neck/shoulder of the die while rotating with the drill, in and out several times. Rinse & clean with solvent, dry the die, and the problem is solved.
 
I am just prepping a box of 100 for as we speak.
The neck OD sizing with a bushing and the neck ID madrell sizing is done, brass neck ID polishing is done...
Measuring right now the neck wall thickness and sorting in two batches...
0.014" and up and 0.013" and below, I have seen on couple pieces the comparator needle want to dance, I put those brass aside.
Someone would say what a heck, 0.001" won't make a difference ?!
I my be wrong, but,
To add to that story if the brass neck annealing is not consistent, and you do = toss around a material several times in a mix...
That may explain a brass build up on a neck when you sizing next time??
 
dgradinaru said:
RCBS brand. I had a spare set of new dies, sealed in the box that I opened last night, deburred, chamfered the brass sprayed it with lube and this is the way it came out. I've been reading up on this and a few from other forums have made mention that the die needs to be polished.

PNlorxq.jpg
Click to expand...
You mention spray lube. Curious what type of spray lube your using? We used to be able to get the Hornady cans up here but they changed the formula and people started having issues with the new stuff, then it became unobtainable due to import restrictions. Perhaps try cleaning the dies with a spray can of carb cleaner and compressed air and try a different lube. Don't forget to lube the inside of the neck too. RCBS and any brand should only be cleaned before use. I guarantee that if you contact RCBS directly they will give you good advise if not just a simple answer to what is happening. They have excellent customer service. Cheers
 
I just wanted to expand on cleaning your dies. I recommend following the manufactures cleaning recommendations.
At about 1:40 of the UR vid he mentions the polish of the dies. I recommend watching his tour of the factory. Really cool vid IMHO with a ton of info.
 
I experienced this on a used set of 223 dies. Ive also boughten used brass and seen those marks.

I "cleaned" the dies with a patch of hoppes, wipe out, wd40, you name it. Didnt fix it.

Then I used a worn out 22 brush in a drill, really slow, with some gray scotch bright wrapped around it and wd40.(maroon would be too coarse IMO) then followed up with white scotch bright and wd 40. Patched out with brake clean.

I use redding wax lube, necks look virtually untouched when sizing after the drill treatment. I chalked it up to having brass or soot cold welded into the die.

Id think it would only take one time sizing a too dry piece of brass to cold weld brass into the neck area of the die. So "brand new" die doesnt mean much.

Can get the grey/white scotchbrite from Lordco. Gray is ultra fine, white is considered a buffing pad.

I measured sized down necks with no expander with a .0000" mitutoyo micrometer before and after the drill treatment and there was maybe .0002" change. If anything, the change was from not measuring striations anymore rather than changing the dimensions of the die itself.

You can also chuck the piece of brass in the drill and polish it with wd40/oil and gray then white pada nd it will virtually remove those striations. Before and after is roughly a .0000" change in size, aka no brass is polished off the neck.

And if your brass feels janky coming back over the expander ball or leaving the inside of the neck looking janky... may as well hit the ball in a drill with some gray/white.

I'm not sure with so much no measureable changes happening it did anything for me other than the brass feels like its sizing better, and it looks better. Im happy about it. Lol
 
I have the same thing happen to me sizing 300 wsm brass. I bought a new set of RCBS to reload for my brother and a buddy hoping to use the die and use a mandrel to simplify reloading. I use Redding with the bushings on mine. What I find odd with the grooves is that it’s one partially grooved around the neck. Both guns still shoot great with different brass, one Winchester and the the other Remington.
 
You must log in or register to reply here.
Back
Top Bottom