Forester Die - leaving markings

[Fore300]

I have a Forester Die that leaves small scratch marks on the case necks after full length sizing. I haven't had this on any of my dies and it doesn't seem to effect the reload but it use to be smooth.
I clean it after each use and have tried polishing with a brass 12gauge brush . Any tips as to what caused it and how to correct?

 

[leonk05]

Is that new brass?

 

[Fore300]

Is that new brass?

No it's been fired numerous times

 

[legi0n]

polish the die with one of those "suppository" felt pads and steel polishing compound

 

[Pottst]

My forester bushing dies left the same marks, didn’t seem to effect the performance of the cartridge from what my groups showed, stay within 1/4 moa.

 

[Fore300]

My forester bushing dies left the same marks, didn’t seem to effect the performance of the cartridge from what my groups showed, stay within 1/4 moa.

Yeah doesn't seem to effect anything. Just more curious what suddenly occurred . I thought maybe some how dirty but the lines are all to even and perfectly straight

 

[Fore300]

polish the die with one of those "suppository" felt pads and steel polishing compound

Thanks I will give this a try

 

[bigedp51]

If it is the standard Forster full length die there is a sharp edge at the neck shoulder junction.

You can use a snug fitting shotgun cleaning mop and a drill to polish. Just put some J&B Bore paste, automotive rubbing compound etc on the mop.

If you have a Forster bushing bump die the bushing needs to be polished.

The rough edges pick up brass and then you have brass rubbing on brass. And a simple polishing will smooth up the rough edges and bring things back to normal.

 

[supernova]

Forster warns against sizing brass that isn't deburred/chamfered for that reason. Ed's explanation is probably why. Copper solvent will dissolve any brass smeared in the die.

 

[Chilly807]

I had an RCBS die do the same thing. A few minutes with a drill spinning a nylon bore brush wrapped in a large cleaning patch soaked with metal polish (Brasso if I remember right) fixed the problem. The shotgun mop would do a good job too.

 

[FirearmsEnthusiast]

OP, are you wet tumbling?

If so, wet tumbling can get the brass “too clean” as it removes the carbon residue that acts as a lubricant on the case neck. Use a tiny amount of your favourite case lube (Like Imperial sizing wax) on the outside of the neck and the problem will go away. I also use some on the inside of the necks to avoid the collet die getting stuck and collapsing the case shoulder.