Rifle cartridge chamfer and deburr - too little or too much?

tateconcepts · February 13, 2014, 01:40 PM

Hello all,

I am getting into reloading rifle cartridges now and I am curious as to what is too little or too much of the Lyman Case Prep system I have. These cases are already trimmed with a saw before they are chamfered along with having a deburr operation performed before they are sized to the correct casing specs. If I don't do this (I tried just tumbling them for 12 hours) they score and scratch the inside of my resizing die (while using the wonderful Hornady One Shot too) if I don't do this first.

At this point, these are casings than have been again trimmed. This time to case length tolerances as specified by a Lyman Case Length trimmer in which they then get the full gamut of the the Lyman Case Prep express. It feels like I need to push down pretty hard to deburr these after the final trim along with almost the same for a 22 degree chamfer on the case mouth (I say this because I worked in both aerospace and energy manufacturing industries on everything from manual turret lathes to CNC and I did manufacture many different detonators for oil and gas drilling / exploration). I personally feel I am putting too much on these but when I don't push down hard enough, there's still a slight OD burr at the case mouth and perhaps inside which will damage these Barnes / Sierra bullets as I found out on the first try!

Can some seasoned reloaders (especially those using 300BLK and/or other semi-autos) provide some feedback and insight? I know the one on the right still has a burr and when loading a few of these in research for testing, the bullet seated well and the jacket was not damaged. Nonetheless, I'm not sure what effect these will have and they will not be using to push the envelope (if they are still usable - which I will and normally I would say this is a weak neck but we're talking 300BLK here not M80 with an ideal 125gr Sierra Match to be loaded on top of some W296. Thought all and everyone? Are these cases too little or likely too much and what is a good picture of just right?

FrankenMauser · February 13, 2014, 02:04 PM

That looks like too much to me.

You want a profile that looks like this:

...not like this:

Brian Pfleuger · February 13, 2014, 02:37 PM

Definitely too much. You don't need a knife edge. Just enough to remove the burs and, on the inside, provide a slight angle to avoid scraping the bullet.

tateconcepts · February 13, 2014, 03:38 PM

I thought so. Seemed excessive but this Lyman Case Prep gets em fast and if you don't exert enough pressure, it still leaves the burr.

Thanks for confirming my suspicion everyone and great documentation. Good thing these were scrap on OAL anyway.

hooligan1 · February 13, 2014, 09:47 PM

I haven't seen brass that sharp before. Did you say you used a saw to trim brass?
It takes about three to four turns from handheld tools to get this camfer and bevel perfect..
. Invest in a decent case trimmer and your brass will love you and go easy with thenpower tools..

Clark · February 13, 2014, 09:59 PM

A guy lectures to his son for 1/2 hour about why he should never drink. The closing sentence is, "But if YOU DO drink, don't mix."

I would like to advise to never trim. Throw away the brass and buy new stuff. Dedicate brass to one rifle and only set the shoulder back .001" or .002" and it should not grow much.

But if you must trim, I made a 44 second video about how to trim, chamfer inside and out, in 6 seconds per case, on the cheap:

http://www.youtube.com/watch?v=nhYlriesNVE

Jay24bal · February 13, 2014, 10:13 PM

In the OP's opening post, he said he is prepping 300 AAC. Along with the mention of a saw, I would assume he trimming .223/5.56 down to the appropriate length for 300 AAC. In this case, trimming is obviously necessary, and a traditional trimmer would take forever. A saw is the way to go.

wncchester · February 13, 2014, 10:35 PM

"...If I don't do this (I tried just tumbling them for 12 hours) they score and scratch the inside of my resizing die..."

No they don't. Steel sizers are case hardened for wear resistance so they're harder than a wood pecker's lips and you can't "score/scratch" one with a file, never mind a few soft brass burrs.

Clark · February 13, 2014, 11:04 PM

Quote:

Jay24bal
A saw is the way to go.

In this low production quality and unlisted video of mine, you can see very fast trimming while I covert 45 colt to 455 Eley a 2:55 into the video.

That is an end mill concentrically trimming a case in a home made collet that is clamped between two V blocks.

There are lots of advantages of this over an asymmetrical sawing operation.

http://www.youtube.com/watch?v=c9bQkVU073Q

Stavman11 · February 14, 2014, 10:12 AM

Ya the outside de-burr looks way to much

I give it a slight inside chamfer then just take the Burr off on the outside... dosent bevel the outside at all... just makes it smooth

tateconcepts · February 16, 2014, 06:54 PM

Those things went bang all right (not the scrap). Not quite at guestimates though, maybe because there wasn't enough brass to crimp on the ones that were done on the outside. I stopped standing when using the Lyman Case Prep and that stopped the overpressure and therefore, undesired results but the outside irritates me.

Yes, you should use a saw if you are converting Lake City brass (I have access to unlimited first fired from DOD usage). It would take too damn long to trim 223 Remington (you know, 5.56MM) down to 300 Blackout. I am not case trimming a half inch here on my case trimmers! I have a special tool that is designed for holding the case under my pipe cutter blade that trims it most of the way but it still needs to be resized afterwards. It has indeed scored my steel dies, I know because I ran some normal 300 BLK brass through afterwards and they also came out with scratches that couldn't be polished out (in 12 hours of tumbling too). It took elbow grease and a few varied grained squares of emery cloth with a dowel rod to take them out. It totally sucked.
The scoring occurred when the cut down brass was forced into size within the 300 BLK die. It might be able to be tumbled out with enough time and the right media but it didn't work for me. I had to deburr mine with prejudice to allow the carbide case trimmer to cut to size. With the deep shoulder, it went like butter instead of resistance but clearly I don't want to repeat this to the finished product as is leaves a weak neck it appears.

I learned quick - thanks guys and Brian! I love the TFL members all - happy shooting and stay safe out there!

tateconcepts · February 16, 2014, 07:38 PM

Oh yeah, hooligan - the Lyman Case Prep is powered. I do a LARGE VOLUME OF BRASS so hand is rarely done except at QA. When I am running four to five cases each day (800-1000 rounds) in each day at each station; hand trimming this quantity would be unproductive and would give a man nothing to work his wanker later!

Gunnery Sergeant Hartman: [chanting] This is my rifle.
Gunnery Sergeant Hartman: [grabbing his crotch] This is my gun.
Marines: This is for fighting.
Marines: [grabbing their crotches] This is for fun.

February 13, 2014, 02:37 PM	#3
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Definitely too much. You don't need a knife edge. Just enough to remove the burs and, on the inside, provide a slight angle to avoid scraping the bullet. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

February 13, 2014, 09:47 PM	#5
hooligan1 Senior Member Join Date: July 18, 2010 Location: Independence Missouri Posts: 4,585	I haven't seen brass that sharp before. Did you say you used a saw to trim brass? It takes about three to four turns from handheld tools to get this camfer and bevel perfect.. . Invest in a decent case trimmer and your brass will love you and go easy with thenpower tools.. __________________ Keep your Axe sharp and your powder dry.

February 13, 2014, 09:59 PM	#6
Clark Senior Member Join Date: December 4, 1999 Location: WA, the ever blue state Posts: 4,678	A guy lectures to his son for 1/2 hour about why he should never drink. The closing sentence is, "But if YOU DO drink, don't mix." I would like to advise to never trim. Throw away the brass and buy new stuff. Dedicate brass to one rifle and only set the shoulder back .001" or .002" and it should not grow much. But if you must trim, I made a 44 second video about how to trim, chamfer inside and out, in 6 seconds per case, on the cheap: http://www.youtube.com/watch?v=nhYlriesNVE __________________ The word 'forum" does not mean "not criticizing books." "Ad hominem fallacy" is not the same as point by point criticism of books. If you bought the book, and believe it all, it may FEEL like an ad hominem attack, but you might strive to accept other points of view may exist. Are we a nation of competing ideas, or a nation of forced conformity of thought?

February 13, 2014, 10:13 PM	#7
Jay24bal Senior Member Join Date: December 13, 2011 Location: Cleveland, OH Posts: 735	In the OP's opening post, he said he is prepping 300 AAC. Along with the mention of a saw, I would assume he trimming .223/5.56 down to the appropriate length for 300 AAC. In this case, trimming is obviously necessary, and a traditional trimmer would take forever. A saw is the way to go. __________________ I like guns. Once Fired Brass, Top quality, Fast shipping, Best prices. http://300AacBrass.com/ -10% Coupon use code " Jay24bal "

February 13, 2014, 03:38 PM	#4
tateconcepts Member Join Date: July 2, 2013 Posts: 39	I thought so. Seemed excessive but this Lyman Case Prep gets em fast and if you don't exert enough pressure, it still leaves the burr. Thanks for confirming my suspicion everyone and great documentation. Good thing these were scrap on OAL anyway.

February 13, 2014, 10:35 PM	#8
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"...If I don't do this (I tried just tumbling them for 12 hours) they score and scratch the inside of my resizing die..." No they don't. Steel sizers are case hardened for wear resistance so they're harder than a wood pecker's lips and you can't "score/scratch" one with a file, never mind a few soft brass burrs.

February 14, 2014, 10:12 AM	#10
Stavman11 Member Join Date: November 4, 2013 Posts: 26	Ya the outside de-burr looks way to much I give it a slight inside chamfer then just take the Burr off on the outside... dosent bevel the outside at all... just makes it smooth

February 16, 2014, 06:54 PM	#11
tateconcepts Member Join Date: July 2, 2013 Posts: 39	Those things went bang all right (not the scrap). Not quite at guestimates though, maybe because there wasn't enough brass to crimp on the ones that were done on the outside. I stopped standing when using the Lyman Case Prep and that stopped the overpressure and therefore, undesired results but the outside irritates me. Yes, you should use a saw if you are converting Lake City brass (I have access to unlimited first fired from DOD usage). It would take too damn long to trim 223 Remington (you know, 5.56MM) down to 300 Blackout. I am not case trimming a half inch here on my case trimmers! I have a special tool that is designed for holding the case under my pipe cutter blade that trims it most of the way but it still needs to be resized afterwards. It has indeed scored my steel dies, I know because I ran some normal 300 BLK brass through afterwards and they also came out with scratches that couldn't be polished out (in 12 hours of tumbling too). It took elbow grease and a few varied grained squares of emery cloth with a dowel rod to take them out. It totally sucked. The scoring occurred when the cut down brass was forced into size within the 300 BLK die. It might be able to be tumbled out with enough time and the right media but it didn't work for me. I had to deburr mine with prejudice to allow the carbide case trimmer to cut to size. With the deep shoulder, it went like butter instead of resistance but clearly I don't want to repeat this to the finished product as is leaves a weak neck it appears. I learned quick - thanks guys and Brian! I love the TFL members all - happy shooting and stay safe out there!

February 16, 2014, 07:38 PM	#12
tateconcepts Member Join Date: July 2, 2013 Posts: 39	Oh yeah, hooligan - the Lyman Case Prep is powered. I do a LARGE VOLUME OF BRASS so hand is rarely done except at QA. When I am running four to five cases each day (800-1000 rounds) in each day at each station; hand trimming this quantity would be unproductive and would give a man nothing to work his wanker later! Gunnery Sergeant Hartman: [chanting] This is my rifle. Gunnery Sergeant Hartman: [grabbing his crotch] This is my gun. Marines: This is for fighting. Marines: [grabbing their crotches] This is for fun.