Edge left on brass after trimming

jjacks1752 · October 28, 2009, 10:27 AM

After resizing, trimming, chamfering and deburring some new 7mm mag brass the other night I noticed that there is still a slight edge left on the outside of the rim of the case neck. It is not a substanial edge but it is enough that if you drag your fingernail from the shoulder of the case up the neck you will feel it. My question here is does this have an effect on accuracy and if so how do I go about removing it?

Thanks,
John

Edward429451 · October 28, 2009, 11:46 AM

More deburring.

GeauxTide · October 28, 2009, 11:48 AM

Chamfer some more on the outside. It usually takes me about 10 turns on the outside and only a couple on the inside.

amamnn · October 28, 2009, 04:41 PM

I know, I know, picky, picky--but to avoid and misunderstanding--chamfering takes place inside the neck and deburring on the outside.
Edward had the problem solved in two words---until...........

David Wile · October 28, 2009, 06:56 PM

Hey Jacks,

I chamfer/deburr all my brass when I first get it and thereafter when I have need to trim it. My intent is to get a nice chamfer on the inside of the neck, so I generally chamfer first, then debur the outside, and follow that with the lightest of chamfer again for the inside. It take a little practice to get first get it right, but once you have the feel for it, it moves right along.

One of the nice things about a good chamfer on bottleneck cases that only have two die sets is that I can usually seat my gas checked bullets without using any flare on the mouth.

Best wishes,
Dave Wile

BigJakeJ1s · October 28, 2009, 09:16 PM

Quote:

I know, I know, picky, picky--but to avoid and misunderstanding--chamfering takes place inside the neck and deburring on the outside.

Since most combination chamfer/deburring tools work by putting a chamfer (a beveled edge) on both inside and outside edges of the neck, chamfer applies to both. The difference in purpose is that you actually want to put more of a bevel on the inside, to help smooth the seating process, whereas on the outside, you just need enough bevel to remove the burr from trimming the neck length.

Hope this helps,

Andy

Hog Buster · October 28, 2009, 11:02 PM

I presume you're using some form of rotary trimming tool. If so don't force it to try and cut too quick. If you do they have a tendency to flare the case, brass being a fairly soft metal. This is more pronounced on the outside than on the inside. The reason for this is that the pilot stops it on the inside but nothing stops it on the outside. Generally speaking the same holds true for the burrs left from trimming. More on the outside than on the inside.

As for accuracy, I dont think it makes much difference as long as the round will chamber.

Oh yeah, chamfer/deburr till it's gone, or if it's really bad run it thru the sizing die then chamfer/deburr

jjacks1752 · October 29, 2009, 03:02 PM

Sounds good, I will try to lighten up on the pressure I put on the case trimmer and then remove what edge is left with the deburring tool. Thanks to everyone for the advice.

ord03 · October 29, 2009, 08:37 PM

I'd recommend an inside neck chamfer using a VLD reamer (about 22 degree angle) over the standard reamer. Makes seating bullets so much smoother. Just don't over-do it.

Edward429451 · October 29, 2009, 09:02 PM

You do not bevel the outside of the case, only slightly the inside but not enough to be sharp. The outside is straight and square.

snuffy · October 30, 2009, 12:58 AM

Quote:

ord03

VLD Reamer
I'd recommend an inside neck chamfer using a VLD reamer (about 22 degree angle) over the standard reamer. Makes seating bullets so much smoother. Just don't over-do it.

+1 Precisely. And here's where to get it.

http://www.midwayusa.com/viewProduct...tNumber=342199

The standard chamfer tools leave a too abrupt inside edge on the brass @ 45 Degrees angel. The VLD tools taper is much longer, 22 degrees, eases the bullet into the neck more gradually.

October 28, 2009, 10:27 AM	#1
jjacks1752 Junior Member Join Date: March 10, 2009 Posts: 3	Edge left on brass after trimming After resizing, trimming, chamfering and deburring some new 7mm mag brass the other night I noticed that there is still a slight edge left on the outside of the rim of the case neck. It is not a substanial edge but it is enough that if you drag your fingernail from the shoulder of the case up the neck you will feel it. My question here is does this have an effect on accuracy and if so how do I go about removing it? Thanks, John

October 28, 2009, 04:41 PM	#4
amamnn Senior Member Join Date: May 13, 2006 Location: WA, the left armpit of the USA Posts: 1,323	I know, I know, picky, picky--but to avoid and misunderstanding--chamfering takes place inside the neck and deburring on the outside. Edward had the problem solved in two words---until........... __________________ "If the enemy is in range, so are you." - Infantry Journal

October 28, 2009, 11:02 PM	#7
Hog Buster Senior Member Join Date: October 26, 2009 Location: Pointe Coupee, Louisana Posts: 772	I presume you're using some form of rotary trimming tool. If so don't force it to try and cut too quick. If you do they have a tendency to flare the case, brass being a fairly soft metal. This is more pronounced on the outside than on the inside. The reason for this is that the pilot stops it on the inside but nothing stops it on the outside. Generally speaking the same holds true for the burrs left from trimming. More on the outside than on the inside. As for accuracy, I dont think it makes much difference as long as the round will chamber. Oh yeah, chamfer/deburr till it's gone, or if it's really bad run it thru the sizing die then chamfer/deburr Last edited by Hog Buster; October 28, 2009 at 11:11 PM.

October 29, 2009, 08:37 PM	#9
ord03 Junior Member Join Date: March 20, 2009 Location: Texas Posts: 3	VLD Reamer I'd recommend an inside neck chamfer using a VLD reamer (about 22 degree angle) over the standard reamer. Makes seating bullets so much smoother. Just don't over-do it.

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October 28, 2009, 11:46 AM	#2
Edward429451 Junior member Join Date: November 12, 2000 Location: Colorado Springs, Colorado Posts: 9,494	More deburring.

October 28, 2009, 11:48 AM	#3
GeauxTide Senior Member Join Date: April 20, 2009 Location: Helena, AL Posts: 4,423	Chamfer some more on the outside. It usually takes me about 10 turns on the outside and only a couple on the inside.

October 28, 2009, 06:56 PM	#5
David Wile Senior Member Join Date: June 14, 2001 Location: Mechanicsburg, PA Posts: 585	Hey Jacks, I chamfer/deburr all my brass when I first get it and thereafter when I have need to trim it. My intent is to get a nice chamfer on the inside of the neck, so I generally chamfer first, then debur the outside, and follow that with the lightest of chamfer again for the inside. It take a little practice to get first get it right, but once you have the feel for it, it moves right along. One of the nice things about a good chamfer on bottleneck cases that only have two die sets is that I can usually seat my gas checked bullets without using any flare on the mouth. Best wishes, Dave Wile

October 29, 2009, 03:02 PM	#8
jjacks1752 Junior Member Join Date: March 10, 2009 Posts: 3	Sounds good, I will try to lighten up on the pressure I put on the case trimmer and then remove what edge is left with the deburring tool. Thanks to everyone for the advice.

October 29, 2009, 09:02 PM	#10
Edward429451 Junior member Join Date: November 12, 2000 Location: Colorado Springs, Colorado Posts: 9,494	You do not bevel the outside of the case, only slightly the inside but not enough to be sharp. The outside is straight and square.