? re case trimming


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Lee Roder
December 11, 2009, 07:36 PM
My War Baby's expected early next year :evil: from the CMP so to get ready :D I've been reading everything about 30 carbine I can find BUT :confused: I've found this at thecmp.org in the help stickies (yes I read those) as justification for trimming new cases:

"New cases are sometimes out of round, dented, too long, or have case mouths long on one side and shorter on the other side. The best practices recommendation is to full length resize them, case mouth expand them, and then trim them to length as you would any other fired case."

thus challenging my understanding of The Process. I've always flared AFTER "trimming".

I don't understand.

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EddieNFL
December 11, 2009, 07:41 PM
News to me.

rfwobbly
December 11, 2009, 07:46 PM
External "sizing" doesn't always get a case round. Rarely, but sometimes, a case needs pushing out with the internal expander to become truly round again to achieve the best trim results.

The "expander" is the lower part of the "belling" tool. The key to their statement here is that they said "expand" and not "bell". So they are suggesting running the expander in far enough to make the case mouth round, without going deep enough to flair the case mouth.

The step may sound excessive, but I think they are simply covering all the bases.

Hope this helps!

243winxb
December 11, 2009, 07:46 PM
You need to make the mouth round so the pilot will fit, dont flare/bell the mouth. http://i338.photobucket.com/albums/n420/joe1944usa/th_expander_1.jpg (http://i338.photobucket.com/albums/n420/joe1944usa/expander_1.jpg) Photo shows a 38, Not a 30 carbine.

Randy1911
December 11, 2009, 07:48 PM
They are saying to expand without flaring so the case trimmer pilot will fit into the case mouth.

Walkalong
December 11, 2009, 08:39 PM
Deleted on account of not paying attention. Arghh.

See post #12

Lee Roder
December 11, 2009, 09:23 PM
OK so "expand" and "bell/flare" are not the same. Got it (I think). Thanks guys.

Walkalong
December 12, 2009, 11:00 AM
Deleted on account of not paying attention. Arghh.

See post #12

EddieNFL
December 12, 2009, 12:28 PM
External "sizing" doesn't always get a case round. Rarely, but sometimes, a case needs pushing out with the internal expander to become truly round again to achieve the best trim results.

Makes sense. Trimming rifle cartridges brings bottleneck to my mind. Gotta think outside the box.

Walkalong
December 12, 2009, 04:39 PM
If your pilot fits properly, it will hold it round while it is being trimmed, besides, unless you are loading match ammo for a world class gun, it will never make a difference as long as the case mouth is close enough to round to go over a properly fitting pilot.

jr_roosa
December 12, 2009, 08:04 PM
I've never belled rifle brass anyway. I deburr the case mouth on all brass (new, old, trimmed, and not) and I have no problems with the bullet going in smoothly.

With new brass for my Garand I full length size (most winchester brass is shorter than my chamber anyway so it's practically neck sizing), check length, trim long brass (I've never had a long winchester case), deburr all the case mouths, and load as per usual. I don't care if the mouth is a little off square since they all need trimming after the first firing anyway, and I don't think that it affects accuracy enough to matter.

-J.

Walkalong
December 12, 2009, 08:10 PM
For some reason I had pistol calibers on my mind during this thread, so one will have to disregard some of what I have posted.

-------------------------------------------------------------------------------------------

Bottle necked rifle caliber pilots for trimmers are designed to fit cases which have been sized and expanded. Not so with straight walled rifle calibers. I'll learn to pay attention better someday,.... maybe. :banghead:

Straight walled pistol caliber pilots are designed to fit cases which have been sized, but not expanded. This would include the .30 Carbine rifle cartridge.


There. I think I got it right this time. :p

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