Brass Trimming

Re: post #18
Yes I realize I shouldn't have used "flaring" in place of chamfering since chamfering doesn't result in a flare. But the main point is that a taper is not the least bit necessary for seating jacketed bullets, but of course doesn't hurt anything, other than perhaps removing excessive brass from inside the case mouth and ending up with the knife edge around the case neck. That does happen. So I will take back the use of the term flaring except as it applies to the use of the Lyman M die when seating lead bullets in rifle cases or any bullet into cases like .45-70s or .458s. But there is still a distinction between deburring and chamfering, and to go one step farther, flaring or belling.
 
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I guess I called it wrong saying chamfer. Just use little Lee tool and run a few times on outside of case and a slight hit inside. Deburring I guess.
 
Mixing sheep & apples her I think:eek:

Chamfer is INSIDE the case neck & done properly helps start FB bullets into the case neck.

Deburr is OUTSIDE of the case neck & allows smoother feeding & chambering.

Neither should be done to excess. You don't want to create a sharp edge t the front of the case, just remove excess "stuff" from the trimming process.
 
But the main point is that a taper is not the least bit necessary for seating jacketed bullets,
Click to expand...

If you add in the word "most" and "in bottle necked cases", then I would agree with the statement.

Because there are exceptions. I will agree it can be overdone, and there is no reason to create a "knife edge" but a little chamfer can help, a lot.

And a good chamfer "fills the gap" between just simple removal of burrs left from trimming and the expansion of a Lyman M die.

Case in point (pardon the pun) the .22 Hornet. The brass is very thin. Sized and loaded the same way I had been doing for 30+ years with a dozen other (larger, thicker) rifle cases, I was losing cases to buckling during bullet seating, even being very careful and slow.

A couple quick twists with the chamfering tool, putting a slight bevel on the inside of the case mouth eliminated the problem, without needing to resort to an expander die.

Sometimes, it is a bit necessary...
 
Re: 44amp
Yes I'll gladly add "most" and "in bottle necked cartridges". The latter is most important since we know that straight walled cases like .38-55s, .375 Winchesters, .45-70s and .458s require flaring with something like the Lyman M die (chamfering is not capable of doing the job sufficiently) to keep from collapsing case necks during seating. The popular Lyman 49th Edition does not have a glossery of terms and does not seem to mention the term "chamfering" anywhere in the literature. However some three or four times the term "deburred" is mentioned and they all read something like this one: "After trimming all cases must be lightly deburred on the inside and outside of the case mouths." But I think we all agree that chamfering implies removing more brass from inside the case mouths than just "lightly deburred". It's then a matter of whether the perceived advantage of chamfering is actually valid--some say yes, others say no--at the expense of thinning the case mouths.
 
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Trim after F/L sizing, Deburr inside & out on the cases. Are you checking your headspace, bolt action no more then .002 RCBS compitition shell holders & precision mic work great. How are you preping your brass from start to finish.
 
straight walled cases , hardly ever trim them.

Rifle and if I do decide to trim straight walled cases, after firing, before resizing.
Technically you are supposed to do it after sizing, but my cutters will not enter the necks after sizing. Had a Pacific trimmer, bought an expensive Forster Trimmer and it did the same thing! So I just trim them before sizing.
It may not be right but at least they are all the same length when I'm done.

Gary
 
Re: Gary
Yes, you do what you have to do. There are usually always exceptions to the general rules. Straight walls play by different rules.
 
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