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-   -   cross section of a smiley (http://glocktalk.com/forums/showthread.php?t=1403261)

Yondering 02-20-2012 23:53

cross section of a smiley
 
I cut open a couple pieces of brass that bulged in my Lone Wolf barrel, to see where the bulge happened relative to the web of the case. This is a newer barrel, bought in December 2011. I thought the picture was interesting enough to post here.

This is a 40 S&W case, didn't have any bulged 10mm handy, but the internal dimensions on the 10 and 40 are pretty much the same other than the primer pocket.

http://i24.photobucket.com/albums/c2...c/IMG_0543.jpg

Any Cal. 02-20-2012 23:58

Do you have any load data for that one, or any idea of what kind of pressure it took to do that?

Yondering 02-21-2012 00:11

I don't know what kind of pressure that was. I can tell you that it's a good example of Blue Dot being inverse temp sensitive; this is a load I worked up a couple summers ago, and was about 0.5 gr less than what caused light smileys at that time.

The load was a 220gr WFN cast lead at 1.260" OAL, over 9.5gr Blue Dot and a PMC SP primer. Velocity was a bit over 1250 fps in my 6.6" barrel; in the warm weather it went over 1300 fps with no smileys. Odd.
I wouldn't work up towards this load with most 220gr bullets BTW, the one I'm using is designed for maximum case capacity, most aren't, especially the truncated cone and semi wadcutter designs.

gofastman 02-21-2012 00:25

very cool, nice work

_The_Shadow 02-21-2012 09:31

Yondering, Great picture clearly showing what I have said all along, the metal has started to shear/tear and resizing and or pass thru sizing will not fix that situation to make them safe to re-use period!

You mention that was a 40S&W case, pressures are actuall suppose to be less than that of the 10mm...
I hope you don't mind if I share that visiual with others with questions!

I just finished running about 2000 range pick up 40S&W cases thru my pass-thru-die yesterday, none were smiled, but there were a few that were bulged down low, That area is not reached by normal sizing dies due to the shell holder and the bottom end of most sizing dies are radiused, leaving that area un sized to normal dimentions.
Placing casings in a cartridge case gauge will show exactly what I am speaking of, they will stop short of sliding inside freely because of the case expansion!

Thanks for posting the info!

_The_Shadow 02-21-2012 10:10

One other thing I have given some thought to is the metallurgy of the brass used these days. Brass can have a wide range of alloy. Things that affect strength of the casings...

Annealing (v) Multi-phased heat and stress treatment that alters the microstructure of a metal adding strength, pliability, and hardness.

Ductile, Ductility (v) A physical quality ascribed to a metal that will permit plastic elongation (wire drawing) without fracturing.

Forging (Forged) (v) Heating a metal to a temperature where the metal becomes malleable (red hot) or deforming its shape by compression or exertion of force (hammering or cold forging).

Malleable, Malleability (v) A physical quality ascribed to a metal that can be compressed, deformed, extruded, hammered, and rolled.

Plastic, Plasticity (v) A physical quality ascribed to a metal that can be bent and worked without rupturing. A non-brittle metal.

These terms were borrowed from http://www.allaboutgemstones.com/glo...etallurgy.html to provide some insite to what metals go thru while being produced or used.

Taterhead 02-21-2012 11:35

Excellent photograph. One interesting observation is that the flash hole centerline shifted to the right. It looks like the whole right side of the web shifted and perhaps the size of the flash hole enlarged. Notice how the anvil of the primer is not aligned with the centerline of the flash hole.

Good work.

Yondering 02-21-2012 21:20

Quote:

Originally Posted by _The_Shadow (Post 18610581)
Yondering, Great picture clearly showing what I have said all along, the metal has started to shear/tear and resizing and or pass thru sizing will not fix that situation to make them safe to re-use period!

Yes. I sectioned two bulged cases, but ran the other one through a Lee FCD first to smooth out the bulge, just to see what that looks like. It does the job it's supposed to (let the brass chamber) but that "lip" is still there, and I wouldn't use that brass again.

Edit: pic added of the pass thru sized case.
http://i24.photobucket.com/albums/c2...c/IMG_0578.jpg

You may notice the primer is backed out; this happened either during sectioning or the cleaning afterwards, not from firing.

Yondering 02-21-2012 21:23

Quote:

Originally Posted by Taterhead (Post 18611049)
One interesting observation is that the flash hole centerline shifted to the right. It looks like the whole right side of the web shifted and perhaps the size of the flash hole enlarged. Notice how the anvil of the primer is not aligned with the centerline of the flash hole.

I didn't notice that until you said something. Looking at the case, the flash hole is definitely off center, but not as bad as it looks in the picture. It's not sectioned exactly in half (wanted to keep the primer in there), so there's a little bit of a lip in the flash hole edges that hangs over more on one side.

I did notice the inside base of the case is no longer flat, but leaning outwards near the bulge. I don't know for sure if that's because of the bulge, but it does look that way.

_The_Shadow 02-21-2012 21:56

Quote:

Originally Posted by Yondering (Post 18613666)
Yes. I sectioned two bulged cases, but ran the other one through a Lee FCD first to smooth out the bulge, just to see what that looks like. It does the job it's supposed to (let the brass chamber) but that "lip" is still there, and I wouldn't use that brass again.

Good test, clearly a "SMILE" is there to stay...instead of a "Smile" we should call them a "FROWN"! :crying:

BTW, Flash holes are often off center...:shocked:

Yondering 02-21-2012 22:17

Shadow, another pic for you added above. Bulge on the left this time, after pass through sizing with a Lee FCD. You can see how the case wall has been stretched, and is thinner right above the bulge. A good visual of what you're talking about.

You can also see the "stretch marks" on the inside of the case, following the line of the feed ramp.

TDC20 02-21-2012 23:42

Excellent work Yondering! Thanks for taking the time to do this and for posting pics of the results. Makes me wonder about how many "mysterious KBs" are the result of reloaded brass that has been smiled like this previously.

Yondering 02-22-2012 21:24

Yeah, good question. With this brass, it was pretty obvious after running it through the FCD that it had been smiley-ed and resized, see pic below. With less of a smile though, it might not be noticeable. Or, maybe people just think it's re-usable anyway.

This isn't the best picture, but the brass is shiny from resizing above and below the smile, but the smile is still visible. This chambered just fine before sectioning. This is the piece of brass in the second picture above.
http://i24.photobucket.com/albums/c2...c/IMG_0577.jpg

dsb1829 02-25-2012 08:15

Great pictures. Thanks for posting.

gofastman 02-25-2012 10:57

would these cases be safe to reuse for very light target loads?

_The_Shadow 02-25-2012 19:32

Gofastman, My answer is NO! As I stated before the brass has started to shear, sizing does not push it back in to correct alignment or heal the shearing. That is made very evident by the cross section pictures which Youndering has so graciously provided.

If you have a case blow out, it can damage not only the magazine, ammo, extractor but the shooter as well! It's NOT WORTH IT!

Yondering 02-25-2012 23:56

Quote:

Originally Posted by gofastman (Post 18629123)
would these cases be safe to reuse for very light target loads?

I agree with The Shadow. Part of the problem is "really light target loads" may feel really mild to shoot, but may still reach full pressure, or enough to rupture an already weakened case. How much would that take? That's the question, aint it?

Often, "light target loads" means using Bullseye or another similar fast powder, that will still reach high pressures even though bullet velocity is relatively low.

You may be able to figure out a "target load" with slower powder that really does operate at low pressure, but the risk doesn't seem worth it, just to re-use some trashed brass.

nickE10mm 02-27-2012 13:34

Excellent post, Yondering!

Taterhead 02-27-2012 21:42

I agree Yondering. Great comments. When new brass from Starline is less than 15 cents shipped, not worth it at all.

_The_Shadow 03-21-2012 16:32

Yondering, I pasted some pics and linked this over at 10mmTalk site for others to learn from you great pictorial here!


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