Inside case Neck Chamfering....How much.

[paulT]

For .308 FTR how much material do you guys remove from the Inside of your case necks when Chamfering/deburring case necks
I am currently using an adjustable k&m case neck chamfer tool which has a guide rod to help tool cut concentric to case mouth I then spin case for few seconds in an old socket packed with 00 wire wool
I find cutting a little extra from inside case necks helps centre the bullet for seating which inturn helps reduce any bullet seating runout to a min
anyone else do similar process.

 

[fkimble@charter.net]

You only want to knock off the sharp square edge from turning. You are not trying to make a funnel.

Frank

 

[NZ_Fclass]

Nothing so flash, just the old RCBS "rocket ship" de -burring tool to remove the roughness and any swarf. Followed with a taper reamer of unknown origin to tidy the inside a little, if needed.

 

[Kracken McGraw]

For .308 FTR how much material do you guys remove from the Inside of your case necks when Chamfering/deburring case necks
I am currently using an adjustable k&m case neck chamfer tool which has a guide rod to help tool cut concentric to case mouth I then spin case for few seconds in an old socket packed with 00 wire wool
I find cutting a little extra from inside case necks helps centre the bullet for seating which inturn helps reduce any bullet seating runout to a min
anyone else do similar process.

I turn my case once with a couple of rolls with my fingers while seating to help insure less runout.

 

[markm87]

You only want to knock off the sharp square edge from turning. You are not trying to make a funnel.

Frank

I lightly spin the lyman VLD chamfer tool on bolt gun ammo. The Giraud, which I use for .223 leaves a hell of a chamfer in the neck. Funnel like as you mentioned.

 

[K22]

You only want to knock off the sharp square edge from turning. You are not trying to make a funnel.

Frank

This is a good explanation - do not overdo it.

In addition to "turning", this needs to be done after trimming.

If you don't trim new virgin cases, I would recommend an initial chamfering of the inside and outside of the necks since sometimes they have a rough lip with burrs. Again, do not overdo it, you do not want a knife edge on the lip of the neck.

 

[Mike Samer]

Nothing wrong with a "funnel" as long as it's properly aligned. Don't want a knife edge though. Different brass and bullet heels may react differently to different geometries.

 

[Straightshooter1]

For .308 FTR how much material do you guys remove from the Inside of your case necks when Chamfering/deburring case necks
I am currently using an adjustable k&m case neck chamfer tool which has a guide rod to help tool cut concentric to case mouth I then spin case for few seconds in an old socket packed with 00 wire wool
I find cutting a little extra from inside case necks helps centre the bullet for seating which inturn helps reduce any bullet seating runout to a min
anyone else do similar process.

I get a little of the funneling effect when I chamfer my case necks, but I'm really just after making sure the chamfer is enough to get rid of any burr after trimming. Before I went with 3-way trimming, the challenge I had was making sure my chamfers were square to the trim cut so that the chamfer wouldn't induce any runout. With boattail bullets, any chamfer funneling just isn't really necessary.

 

[Ned Ludd]

It's not about the visual appearance of the case mouth. It's about not damaging the jacket when seating bullets. So the answer is that you remove a sufficient amount of material from the corner/edge of the case mouth so that doesn't happen. You don't need to create a knife blade edge around the case mouth, but there's no reason to be overly stingy, either.

 

[paulT]

Thanks For Replies.