Why scrape burrs after neck-trimming?

Ignition Override · May 3, 2011, 03:19 AM

Is it to allow consistent caliper measurement of the case length, or for other safety reasons? I realize that any internal burrs will scrape bullets and create asymmetrical aerodynamics (like a speed brake/spoiler panel partly extended on just one wing).
What is the main reason to remove External burrs?

My only reloading has been for 'British '303', but just deprimed and now trimming the first cases for 30-06 reloading.
It is LC M2 Ball, which will be used in the Garand (Service Grade, CMP).

GP100man · May 3, 2011, 04:43 AM

So the burrs won`t catch & scrunch a neck & ease bullet seating , a must seating lead bullets !

Sevens · May 3, 2011, 07:29 AM

So you can see what burrs on the inside of the case mouth will do...

What's different on the outside? That cartridge case has to sit in a nice, tight, form-fitting chamber, right?

It just makes sense. Like making a clean cut in a piece of wood, sanding it and then blowing the sawdust out of it before you'd ever think about staining the wood, ya know?

reloader28 · May 3, 2011, 08:30 AM

You need to debur/chamfer because

1. It is very easy to do and takes no effort to improve the looks

2. Because when you chamber the round, a bur can act like a heavy crimp and really raise the pressure

Ignition Override · May 3, 2011, 12:18 PM

That's very clear.
Thanks.

Walkalong · May 5, 2011, 06:33 AM

It is just sloppy not to. It will be an inconsistency. It could possibly cause chambering problems if severe enough. It will interfere with the crimp if crimping.

May 3, 2011, 03:19 AM	#1
Ignition Override Senior Member Join Date: February 18, 2008 Location: About 20 nm from the Big Muddy Posts: 2,884	Why scrape burrs after neck-trimming? Is it to allow consistent caliper measurement of the case length, or for other safety reasons? I realize that any internal burrs will scrape bullets and create asymmetrical aerodynamics (like a speed brake/spoiler panel partly extended on just one wing). What is the main reason to remove External burrs? My only reloading has been for 'British '303', but just deprimed and now trimming the first cases for 30-06 reloading. It is LC M2 Ball, which will be used in the Garand (Service Grade, CMP).

May 3, 2011, 04:43 AM	#2
GP100man Senior Member Join Date: August 1, 2007 Location: Tabor City , NC. Posts: 1,969	So the burrs won`t catch & scrunch a neck & ease bullet seating , a must seating lead bullets ! __________________ GP100man

May 3, 2011, 07:29 AM	#3
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	So you can see what burrs on the inside of the case mouth will do... What's different on the outside? That cartridge case has to sit in a nice, tight, form-fitting chamber, right? It just makes sense. Like making a clean cut in a piece of wood, sanding it and then blowing the sawdust out of it before you'd ever think about staining the wood, ya know? __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

May 3, 2011, 08:30 AM	#4
reloader28 Senior Member Join Date: October 13, 2009 Location: nw wyoming Posts: 1,061	You need to debur/chamfer because 1. It is very easy to do and takes no effort to improve the looks 2. Because when you chamber the round, a bur can act like a heavy crimp and really raise the pressure

May 3, 2011, 12:18 PM	#5
Ignition Override Senior Member Join Date: February 18, 2008 Location: About 20 nm from the Big Muddy Posts: 2,884	That's very clear. Thanks.

May 5, 2011, 06:33 AM	#6
Walkalong Senior Member Join Date: May 30, 2007 Location: Al. Posts: 196	It is just sloppy not to. It will be an inconsistency. It could possibly cause chambering problems if severe enough. It will interfere with the crimp if crimping.