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What's the full-length sizer doing to my new brass

bp78

Sergeant
Full Member
Minuteman
Feb 7, 2011
213
1
45
Central NC,USA
Brand new Lapua .260 brass, Forster full-length benchrest sizer first adjusted all the way down then backed off some left distinct banding around the neck. Any idea what is going here in this photo?
lapua_260_brass.JPG
 
Re: What's the full-length sizer doing to my new brass

What lube did u use?
 
Re: What's the full-length sizer doing to my new brass

I've only seen marks Ike that with not enough lube. Or somehow it's getting wiped off before the neck enters.
 
Re: What's the full-length sizer doing to my new brass

bp78,

Might check the inside of the die, right at the neck/shoulder junction and see if it's a smooth transition. Bore scope's great for this, if you have access to one. If the lube isn't the issue (which it appears to me that it may well be), then I'd suspect a die that just isn't quite as polished as it should be. Might also check the size of the die, as it looks like it's taking the necks down a bit smaller than they really need to be. Can't say for sure without measuring, but that's what it looks like from here.
 
Re: What's the full-length sizer doing to my new brass

BP,
Your case mouth has tiny particles that are coming off, and it is galling your brass, and your die.
First, take your die apart and clean it with a stout solvent, get the brass out of it. Then lube it,neck especialy.
Then if your case mouths aren't dinged up too bad, chamfer and deburr them, this will cure it, of coarse with lube. If they are dinged, just run up through expander, then chamfer.
Your lucky it is Lapua brass, it is clean, other brands would have galled your whole die, espeially from expander pulling loose shit from inside the case.
Lube every 5th case mouth with Imperial. Also, set the die back to where you started, do the whole neck.
Hope this helps, if not pm me.
Most people would have just shot this before prep, what I would recommend to do.
 
Re: What's the full-length sizer doing to my new brass

Thanks guys. Brand new dies and brand new brass. I'll break it down, clean it, and lube as directed to see how it fares.
 
Re: What's the full-length sizer doing to my new brass

its nothing to with the dies ,
we have had the same results with a batch of lapua .308
checked everything , dies,lube etc, its the lapua brass seems to be rough and suface hard. load as usual and shoot,you will find after being fired it will size without any marks
 
Re: What's the full-length sizer doing to my new brass

It is called burnishing. If you want to minimize it, put a little lube on your fingers, spin the neck (not the shoulder) between your fingers, then size.

If you are using an expander ball, it is a good idea to keep a tad bit of lube on it as well.

Brass is a rather abrasive, high stiction material.

Keep the lube OFF the shoulder though.
 
Re: What's the full-length sizer doing to my new brass

as i said previously,
when we had this problem with some .308 lap ,
no matter how much lube or type would stop it happening
new dies/cleaned dies still happened,
its the brass not your equipment or technique
 
Re: What's the full-length sizer doing to my new brass

Nothing I haven't seen a thousand times. Just load them and keep using ISDW, everything will be fine.
 
Re: What's the full-length sizer doing to my new brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dave338</div><div class="ubbcode-body">as i said previously,
when we had this problem with some .308 lap ,
no matter how much lube or type would stop it happening
new dies/cleaned dies still happened,
its the brass not your equipment or technique </div></div>

Take the new Lapua brass and spin it using a cordless drill/screw driver. Knock of the surface roughness with some 0000 steel wool. Will keep the particles from attaching themselves to the inside of the die.

I'd also apply some steel wool to the inside of the die to make sure there isn't some manufacturing residue that's glued itself to the neck portion. If you do those things and still get the marking, call Forster and request that they correct it by either refinishing the Die or replacing it.
 
Re: What's the full-length sizer doing to my new brass

It looks like some thing I had. Maybe the machining formed an arris at the bottom of the die neck. A burr. I polished-rounded over- that "ring" and the striations no longer occurred.
 
Re: What's the full-length sizer doing to my new brass

I use the Redding dies with the ti coated bushings using .335 .334 & .336 all made the marks .
Steel wool on the necks would work for a small batch , unfortunately I was wondering several 100s .
Like some one else said , load and shoot .
 
Re: What's the full-length sizer doing to my new brass

My Forster 308 die has had 10,000+ rounds sized with it. It scores the necks pretty badly, to the point that Dan Warner told me to replace the die when he looked at my dummy rounds I sent in for a re-barrel.

I replaced it w a Redding with the ti nitride coated bushing. It too scores the neck.

The little bit of lube with the fingers helps with the overall sizing feel, so I'm sticking with it.
 
Re: What's the full-length sizer doing to my new brass

I had the same problem with my brass for my 300 winny and redding dies. I freaked and did all the same cleaning to the dies and lube and still did it. So I loaded it, fired it and resized it. No problems after that. I thought that it was just a fluke batch of brass but am glad that I read this. Thanks for the info. Good luck and good shooting!