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to chamfer or not, that's the question

5K views 20 replies 10 participants last post by  beatendeadhorse 
#1 ·
just got my 1000 count lot of 223 resized and crimp removed. Do I need to chamfer the neck before seating bullets? They don't have a chamfer now (once fired federal american eagle). I'm loading 55gr fmj flat base in Hornady custom grade dies on a single stage press.
 
#2 ·
Just a slight chamfer is all you need to let the bullet start into the neck...like just deburring the inside edge. You just need to knock off the square edge left after trimming. If the brass is virgin (untrimmed), it might still have the factory rounded mouth edge left after they tumble the brass. Those you might be fine with not deburring the mouth.

Not sure if it's my technique or not, but the .223 is one of the cartridges that I have problems collapsing the shoulder if the bullet hangs up on the case mouth during seating. For some reason, I don't have near as many problems with the .222.
 
#7 ·
If you have a deburring drill bit, that will work fine as a hand tool to knock off the sharp edge on the inside of the case mouth. Barring that, you can also use a flat-blade screwdriver, either a 3/16" that gets really wide above the tip, or a 1/4" blade you grind down to .22 or so at the tip. You might also try a 1/4" drill bit, but be gentle; that can remove a lot of metal quickly!
 
#8 ·
I went and bought an 8" drill press for removing primer crimps so I could chuck in a chamfer tool and run them just a bit. Would you suggest a tool such as RCBS VLD chamfer (22 degree) or my 45 degree countersink bit for metal work? I'm concerned the 22 degree will take too much away and leave the cannelure crimp weak
 
#9 · (Edited)
If you're chucking into a drill press, I would just stick with your 45° countersink. That works just fine for chamfering the inside of the case mouth. It's how I remove primer crimps too.

If you're using a regular chamfer/deburr tool (or that 22° version), I'd stick with hand powered. They cut pretty aggressively and you can dig in pretty deep if you're trying to power it. Don't ask how I found that out... :rolleyes:

I've never used a 22° tool...didn't even know they made one til you mentioned it. I'd still treat it just like a regular 30 or 45° tool...all you're doing is removing the burr and knocking the sharp edge off, you don't want to remove much metal from the edge as that will make a weaker mouth like you mentioned regardless of what angle the tool is.


Keep in mind when you trim the cases, you'll need to deburr the outside of the case mouth too so you'll need an outside cutter eventually too.
 
#10 ·
Quick example of what to look for.

Left case: Way too much chamfer on the case mouth. This one has a sharp edge on the case mouth all the way around. Done to show what not to do. :)

Center case: Just right. Case mouth still has a nice square edge, but the sharp corner left after trimming has barely been removed on both the inside and outside.

Right case: Freshly trimmed, hasn't been deburred yet. Those two burr edges on the inside and outside are what need to be trimmed off.
 

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#12 ·
perfect, thanks bindernut. I did one with the 45 and it looks like the one on the left. I think I'll do them by hand for more control. Tonight is lock-n-load monday, I'll be sitting in my recliner working brass watching TV. Maybe I can get my son to prime them after I chamfer
 
#13 ·
Anything to deburr the case mouth...the angle isn't important. You just need to knock the square edge off so the bullet doesn't dig in on a sharp corner.
Yep, just knock off the edge, no real chamfer needed. I use a 60 degree countersink 'cause that's what I have in my tool box, but any angle will do as you're only removing .002"-.003" or so...
 
#14 · (Edited)
I have to read these posts more carefully. I assume that you have deprimed, resized, removed factory crimps and trimmed all of your cases.

Great job of explaining chamfering, everyone - especially Bindernut. On reloading fired bulk brass, the Lee case trimmer chucked into a small drill press really saves time. The .223 data in some reloading manuals don't stress the importance of consistant case length enough. As been pointed out on other posts, it is very easy to run into problems at the shoulder while seating and crimping bullets, especially in the .223 for some reason. I've never experianced this problem with thousands of .30 or 7.62 NATO ammo.

Again in chamfering, you only want to remove the burr - not create a 'knife edge'. I really like my RCBS chamfering tool. I also use it to remove the military primer pocket crimp. Some guys like to swage the pockets, and that is great, but I just chamfer out the crimp.
 
#15 ·
If you're chucking into a drill press, I would just stick with your 45° countersink. That works just fine for chamfering the inside of the case mouth. It's how I remove primer crimps too.
Got to thinking about power deburring this afternoon and figured I should expound a bit on my earlier post.

Whether I'm removing primer crimps or deburring case mouths, I don't have the case seated on the table and lower the quill/tool into it. I leave the quill full up and push the case up into the tool just by hand pressure. This way it is fairly easy to feel how much it's cutting.
I think it's too easy to lose the "feel" of the tool's bite when you use the compound leverage of the feed lever/wheel, especially when cutting soft material like brass.
And run the drill as slow as it will go too. Mine goes down to 100rpm and that's what I use for case work.
 
#16 ·
rest assured, I hold the brass in hand and "feel" it being worked. That's just the way I operate.

I ran out of time tonight but tomorrow I will chuck up my 45* bit and dress the inside edge. I need to find a bit to run the outside yet.
 
#17 ·
Got to thinking about power deburring this afternoon and figured I should expound a bit on my earlier post.

Whether I'm removing primer crimps or deburring case mouths, I don't have the case seated on the table and lower the quill/tool into it. I leave the quill full up and push the case up into the tool just by hand pressure. This way it is fairly easy to feel how much it's cutting.
I think it's too easy to lose the "feel" of the tool's bite when you use the compound leverage of the feed lever/wheel, especially when cutting soft material like brass.
And run the drill as slow as it will go too. Mine goes down to 100rpm and that's what I use for case work.
Excellent description, Bindernut! Yes, you can feel the bits "bite" the metal, and too much automation removes that valuable feedback.
 
#18 ·
I measure all my fired cases and if they fall between 1.75 and 1.76, I don't trim and don't chamfer. At 1.76 and above, I trim with a Lee tool using the slow "screwdriver" setting on my drill, then, leaving the case in the holder, I run the inner and outer chamfer/debur tool for just a few revolutions to clean up the mouth. Works for me.

BTW, great graphic Bindernut!
 
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