Underwood 165 GDHP mini-smile :-)

RMM · February 25 2013 11:01:56 PM MST

Hey guys! I was just sorting through some of the brass I collected from my last range visit. G20SF, stock everything.

From left to right:
PMC 200gr (barely any bulge), UW 165 GDHP (tiny line w/bulge), UW 165 GDHP (noticeable line w/bulge), UW 165 GDHP (smiley! ${$default_shocked_smiley}$ )

It is hard to get the lighting right to show the fainter lines, but they are noticeable to me using a flashlight. The bigger "smiley" was very noticeable as soon as I picked up the brass. Do you think it will iron out? ${$default_tongue_smiley}$

DM1906 · February 26 2013 12:25:54 AM MST

Iron out? No. Not a chance. That's the price for (OTC) power. Pitch it and move on.

The_Shadow · February 26 2013 07:19:24 AM MST

Does the "SMILE" on the case equal or exceed that area of case support! Place the case back into the barrel, looking to see if the headspacing and smile line up or if the smile extends further up than the full seated casing.

In other words, was the cartridge backed out of the chamber any, having more smile than the area of no support? ${$default_huh_smiley}$

If it does exceed the lack of support at the feed ramp, then the unlock was too early...

sqlbullet · February 26 2013 07:37:06 AM MST

It will iron out in a push through sizer die.

The better question is whether it is safe to reload. The answer is a definite no for the last one, and a probably no for the next to the last one. Only way to find out for sure on the second to the last one is to subject it to a destructive test, after which you would know if it was reload-able, but will have destroyed the case. So, the functional answer is the last two cases are not safe to reload.

More here: http://10mm-firearms.com/reloading-10mm-ammo/cross-section-of-a-smiley/

RMM · February 26 2013 08:42:32 AM MST

I haven't tried to measure the smiley or put it back in the chamber. If I recall correctly there wasn't nearly that much of the case exposed in the unfired casing, but I could be wrong. I will take a look tonight and let you know what I find.

A week or so ago there was some discussion over at glocktalk about whether or not heavier aftermarket springs actually help delay unlocking. I think that a spring with more preload in theory will help a bit. I do have a 22 lb. ISMI spring which I haven't tried out yet, the next time I shoot some Underwood (from the same box/batch) I will use the spring and see if there is any change in smileys.

Also, I was joking when I asked if it would iron out... I guess that's the danger of not having a face to face conversation with someone. I would never try to reload a case with a visible crease line. At that point the metal is already very fatigued. It would be even more compromised after trying to size it back down.

The_Shadow · February 26 2013 09:32:16 AM MST

Let us know what you find out. I'm glad you mentioned Pre-Load. Someone was posting they actually had a short captive aftermarket setup in their Glock 20 and it would just drop out when he pulled the slide off of the frame...that would mean there is no pre-loading! The factory RSA also fell out in his test even tough the factory rod was slightly longer...

This is where I see a non-captive spring (Wolff Gun Springs two piece rod and 21 lb spring set) being an advantage in my Glock 29, it is pre-loading its pressure fully against the lock up. My S&W 10xx series guns are all non-captive setups from the factory and they too pre-load to hold the slide, barrel and frame in the locked position.

This doesn't allow for any slack at lockup, and the movement is only allowed as recoil overcomes lockup during ejection. I use many used brass and have loaded some to Underwood and SwampFox loads without any "SMILES" but that doesn't mean it can happen...I did find a very lightly smiled brass (it may have been smiled prior to my loading it, just missed during inspection). Some recent test of various loadings, no smiles were noted from Underwood loads, but I did have higher than expected velocity and blown primer from the 135gr Nosler @ 1700 fps instead of 1600 fps. ${$default_shocked_smiley}$

RMM · February 28 2013 10:59:28 AM MST

Quick update:

I went the the range Tuesday night with my wife (yeah, I'm that lucky ${$default_wink_smiley}$ ). I shot about 20 Underwood 165gr and 180 gr. with the 22lb. captive spring. I didn't see any more smileys, but this obviously was not a large enough sample size to be conclusive.

I re-examined the 4 used pieces of brass that are pictured in this thread. I placed each of them in the barrel to see how they fit and how the "smileys" lined up.

-The PMC brass slid in and out fairly easily.

-The two "slightly smiled" pieces of Underwood would slide all the way in, but were pretty tight. I could barely get them out with my fingernail.

-The "heavily smiled" piece of Underwood would NOT go back in the chamber. Furthermore, I can confirm that the smiley lines up with the feed ramp, but it definitely exceeds the unsupported portion of the barrel, as if it did unlock a little early. I will try and get some pictures sometime this weekend and post them here. (Trying to make it through another week of law school first.)

I'm wondering now if I screwed up by buying a captive guide rod instead of the Wolff setup. I don't have a good way right now to measure the amount of preload that the different springs are placing on the slide. I would be very interested to see how much amount of preload varies between different springs and how much it affects lockup.

REDLINE · March 01 2013 09:45:21 PM MST

Looking forward to the pics.

RMM · March 01 2013 11:30:31 PM MST

Here are some pictures. I'm too tired to write too much about them right now $:-\$ , but tomorrow morning I'll post some more thoughts. These pictures are of the same cartridges that are pictured earlier in this thread.

Unfired Underwood 10mm 165gr. Here you can see the case support.

Side angle shot of the unfired UW 10mm.

Side angle shot of the fired PMC 200gr. 10mm

Side angle shot 1 of the fired UW 10mm with only a SLIGHT line/crease. This one was tight to pull back out with just my fingers, but I was able to.

Side angle shot 2 of the fired UW 10mm with only a SLIGHT line/crease.

Shot 1 of the fired and smiley'd ${$default_grin_smiley}$ UW 10mm. Here you can see how the smiley lines up with the feed ramp.

Shot 2 of the fired and smiley'd UW 10mm. Here the case is pushed down as far is it will go without pushing too hard, which ended up being where the smiley hits the chamber/feed ramp.

Side angle shot of the fired and smiley'd UW 10mm. You can see that the smiley occurred with the brass at least partially extracted from the chamber.

4949shooter · March 02 2013 03:45:00 AM MST

Interesting. And the Underwood round/case was fired with a stock spring?

RMM · March 02 2013 08:35:57 AM MST

Quote from: 4949shooter on March 02 2013 03:45:00 AM MST
Interesting. And the Underwood round/case was fired with a stock spring?

Yes, all of these rounds were fired with a stock spring with around 200 rounds through it.

The_Shadow · March 02 2013 09:59:33 AM MST

RMM, very nice pictures and it helps to explain what I suspected happen. Seeing the "SMILE" exceed the actual area unsupported by the chamber, shows that unlock or movement added to the situation. Many people swear that the case can't be pulled out while under pressure, clearly this shows some movement or not fully locked (Out of battery firing)(Not suppose to happen in Glock) is occurring in this instance.

I would give some thought to the RSA, I have been reading where some are seeing their RSA drop out with no pre-loaded pressure being applied by their factory setup and some aftermarket captive systems. Other thing to look into is the locking block and barrel lug fit and angles.

Thanks for the visuals!

REDLINE · March 02 2013 10:15:14 AM MST

Quote from: RMM on March 01 2013 11:30:31 PM MSTSide angle shot of the fired and smiley'd UW 10mm. You can see that the smiley occurred with the brass at least partially extracted from the chamber.

Sure enough, check that out.......I always wanted to see actual clear evidence of the same, and there it is. TYVM for posting the pics! Now if we could find a way to solve the issue once and for all with FULL POWER 10MM loads we'ld be in business.

REDLINE · March 02 2013 10:19:04 AM MST

Forgot to ask; RMM, would you say the case was retracted a full eighth of an inch when it smilied?

RMM · March 02 2013 10:52:49 AM MST

Quote from: REDLINE on March 02 2013 10:19:04 AM MST
Forgot to ask; RMM, would you say the case was retracted a full eighth of an inch when it smilied?

I will get my calipers out tonight when I get back home and see if I can get a ballpark measurement.

I might have to try and cut this casing apart to see what it looks like on the inside. I will have to see what I can do with my little rotary tool.

This is an interesting puzzle to me. I am in law school now, but I studied the applied sciences as an undergraduate. I spent many hours in physics and chemistry labs. Although all of the calculations I've seen from knowledgeable people say that either (1) too much force would be required to extract the cartridge while under that much pressure (so much that the extractor would rip off the case rim), or (2) the extremely high chamber pressure (enough to smiley the brass) occurs too quickly for the brass to smiley as it's being extracted.

Obviously I've just made some very generalized statements here, but what we're seeing does not jive with either theory. When your calculations and actual results do not correlate, then you're missing something.