question on brass resizing [Archive] - Glock Talk

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12dmax
11-10-2010, 21:18
Ok fellas need some opinions here. My fired brass expands to .426, it resizes to .418 except for just forward of the case head .422. They all guage fine and I have no feed issues, would you all run them through a pass through die or would I just be working the brass needlessly? Lee 4 die set.

Thanks Boys!

MakeMineA10mm
11-10-2010, 22:18
If it fits in a cartridge gauge, than it's within spec for all commercial ammo in that caliber (in this case 10mm), which means it should fit in any in-spec firearm in that chambering.

Second, if it feeds flawlessly in your firearm, there's no problem.

So, more work is needless.

12dmax
11-11-2010, 16:59
If it fits in a cartridge gauge, than it's within spec for all commercial ammo in that caliber (in this case 10mm), which means it should fit in any in-spec firearm in that chambering.

Second, if it feeds flawlessly in your firearm, there's no problem.

So, more work is needless.

what I figured, thanks for your input:thumbsup:

12dmax
11-16-2010, 17:03
So why does the brass at the case head only resize to .422 and not .418?

MakeMineA10mm
11-16-2010, 20:42
Couple reasons most likely:

1. The thicker brass at the case head is less springy than the thinner brass farther up the case walls, and

2. The die is probably chamfered somewhat at the bottom to allow easier/better feeding of the case into the die, and hence, it doesn't squeeze as much.

_The_Shadow
11-16-2010, 21:37
Sizing die is slightly tapered to allow better neck tention and positive feeding!

Here is the rub, Likw MakeMineA10mm posted many sizing dies especially carbide have a generous radius to accept the case mouth more easily even if slightly out of round. Also the area occupied by the shell holder along with the generous radius may not iron out bulging which is very near the start cut of the extractor cut.

The pass thru dies really help to insure fitting a cartridge gauge for positive feeding.
I just ran a bunch thru the LEE FCD with the seater and sleve removed to recondition them, these were shot from the MP-5 10mm with the fluted chamber.

Careful inspection will reveal discrepencies, but if you have brass in question it doesn't hurt to run them thru a Pass Thru die system.

MakeMineA10mm
11-17-2010, 14:12
And, just to follow-up on Shadow's excellent post, here's another way to look at the pass through dies:

People use (and companies who make them market) the pass-through dies to do all kinds of sizing jobs. There are: iron out the Glock Bulge/Smilie, size brass that has been fired in a generous-chamber (like the MP5/10 brass), to get it to fit a cartridge case gauge, and to "recondition" fired brass.

For the "home-user" who is not selling or giving away his ammo to others, there is no reason to "recondition" brass as long as it fits your gun(s). Also, no reason to worry about whether it fits a case guage, as long as it works in your gun(s).

For the commercial reloader, a "reconditioning" (which I define as taking the brass back to minimum SAAMI specs, so there's no question of it fitting/working in any reasonable-quality gun), or sizing to fit a case gauge makes sense. They don't know what kind of firearm the ammo will be expected to feed, fire, and function in, so they need to zero that ammo out to a minimum.

Last, we have the Glock Bulge/Smilie. Personally, I scrap this brass. If you take 100 smilied cases that have been run through a pass-through die, you'll find some percentage to still have a weak spot in the brass caused where the brass thinned from swelling. (Usually it looks like a pinched area on the outside of the case IF it's visible at all.) The pass-through dies do not return that displaced brass back to where it came from in a neat, orderly, perfect manner. This brass should be scrapped. Replacement once-fired brass is a lot cheaper compared to a trip to the ER and hospital bill, not to mention repair/replacement of a firearm...

Now you have the long-version. This is why I said you were fine without the pass-through die.

12dmax
11-17-2010, 16:02
Most definetly dont see a need for pass thru die, the cases fit just fine in guage and chamber. cases mic .426 full length after shooting. Size die is chamfered at mouth, just seemed nutz that it does resize the case head down .004 but thats it. Thanks for your your replies boys!