Can typical chamfer & deburring affect case length

brycealbright · November 26, 2014, 10:27 PM

I will be selling converted .223 to 300 blackout reloading brass in a few days. SAMMI specifies 1.358, that I can do, but what kind of problem can come about when I chamfer & deburr the brass afterwards.

rg1 · November 27, 2014, 01:20 AM

Maximum overall 300 Blackout case length is 1.368". Just note that after running the cutoff case through your sizing die length will increase a few thousandths after sizing. If you cut them too long it takes more case trimming to remove that extra length. Length can grow about .008" or so. Minimum case length is 1.368 minus .020" but most prefer to have the lengths come out at 1.360-1.365". Chamfering and deburring case mouths should have nothing to do with overall length of cases but only remove sharp case mouth edges.

brycealbright · November 27, 2014, 05:26 AM

Appreciate your help, have a good Thanksgiving.

frogo207 · November 27, 2014, 10:37 PM

sorry double post

frogo207 · November 27, 2014, 10:43 PM

When you chamfer/deburr a case mouth you only take off the square edge of your cut. There should be some of the flat cut left, you are not trying to sharpen the case mouth like a hole punch.

Just a light touch and slight twist by hand with my LE Wilson tool inside and out does it.

brycealbright · November 28, 2014, 07:05 AM

Appreciate your help.

condor bravo · November 28, 2014, 09:46 PM

I question why more reloaders, when preparing cases, choose to chamfer rather than use a flaring tool to bell case mouths. If just removing inside burrs, fine, but going much farther with the tool (chamfering) can result in cutting a knife edge ridge around the case mouth rather than keeping the mouth square. A chamfer or flare is usually not even needed whem seating jacketed bullets so why remove material from the case mouth. If loading lead bullets the small chamfer flare is not sufficient and bullet shaving or neck collapsing will occur. If belling must be done, and for lead rifle bullets it must be, use a proper flaring tool. This would be the Lyman (or I think RCBS has one) M Expander die. This will flare the neck as needed without removing any metal. They are priced around twenty dollars and one bullet diameter size fits all. Meaning that the same die is good, for instance, for all .30 calibers. A taper crimp should then be used to remove the flare upon seating the bullets.

So I would ask the OP if the purchaser of the brass would really like the cases chamfered?

Damon555 · November 29, 2014, 11:35 PM

Bottle necked rifle brass is neither belled nor flared....Chamfering just knocks the burrs off so you don't mar the bullet during the seating operation.

To answer the OP's question.....No. If you are making the cases shorter than you are doing it all wrong. The whole idea is to just smooth up the neck a little.

November 26, 2014, 10:27 PM	#1
brycealbright Member Join Date: October 12, 2014 Posts: 28	Can typical chamfer & deburring affect case length I will be selling converted .223 to 300 blackout reloading brass in a few days. SAMMI specifies 1.358, that I can do, but what kind of problem can come about when I chamfer & deburr the brass afterwards.

November 27, 2014, 05:26 AM	#3
brycealbright Member Join Date: October 12, 2014 Posts: 28	Thanks rg1 Appreciate your help, have a good Thanksgiving.

November 27, 2014, 10:37 PM	#4
frogo207 Member Join Date: May 17, 2009 Location: Mount Desert Island MAINE Posts: 19	sorry double post __________________ The west was not won with a registered gun. Don't let our government make us into outlaws. NRA Life Member Last edited by frogo207; November 27, 2014 at 10:48 PM.

November 27, 2014, 10:43 PM	#5
frogo207 Member Join Date: May 17, 2009 Location: Mount Desert Island MAINE Posts: 19	When you chamfer/deburr a case mouth you only take off the square edge of your cut. There should be some of the flat cut left, you are not trying to sharpen the case mouth like a hole punch. Just a light touch and slight twist by hand with my LE Wilson tool inside and out does it. __________________ The west was not won with a registered gun. Don't let our government make us into outlaws. NRA Life Member

November 28, 2014, 07:05 AM	#6
brycealbright Member Join Date: October 12, 2014 Posts: 28	Thanks Appreciate your help.

November 27, 2014, 01:20 AM	#2
rg1 Senior Member Join Date: November 6, 2001 Posts: 1,125	Maximum overall 300 Blackout case length is 1.368". Just note that after running the cutoff case through your sizing die length will increase a few thousandths after sizing. If you cut them too long it takes more case trimming to remove that extra length. Length can grow about .008" or so. Minimum case length is 1.368 minus .020" but most prefer to have the lengths come out at 1.360-1.365". Chamfering and deburring case mouths should have nothing to do with overall length of cases but only remove sharp case mouth edges.

November 28, 2014, 09:46 PM	#7
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	I question why more reloaders, when preparing cases, choose to chamfer rather than use a flaring tool to bell case mouths. If just removing inside burrs, fine, but going much farther with the tool (chamfering) can result in cutting a knife edge ridge around the case mouth rather than keeping the mouth square. A chamfer or flare is usually not even needed whem seating jacketed bullets so why remove material from the case mouth. If loading lead bullets the small chamfer flare is not sufficient and bullet shaving or neck collapsing will occur. If belling must be done, and for lead rifle bullets it must be, use a proper flaring tool. This would be the Lyman (or I think RCBS has one) M Expander die. This will flare the neck as needed without removing any metal. They are priced around twenty dollars and one bullet diameter size fits all. Meaning that the same die is good, for instance, for all .30 calibers. A taper crimp should then be used to remove the flare upon seating the bullets. So I would ask the OP if the purchaser of the brass would really like the cases chamfered? Last edited by condor bravo; December 1, 2014 at 06:41 PM.

November 29, 2014, 11:35 PM	#8
Damon555 Senior Member Join Date: January 11, 2012 Posts: 384	Bottle necked rifle brass is neither belled nor flared....Chamfering just knocks the burrs off so you don't mar the bullet during the seating operation. To answer the OP's question.....No. If you are making the cases shorter than you are doing it all wrong. The whole idea is to just smooth up the neck a little.