357Sig KB w/KKM BBL Underwood Ammo

The_Shadow · March 03 2013 07:53:42 AM MST

G31 (.357 Sig) KB'd with a KKM barrel. Chamber end opened up. Shooter OK, Underwood ammo mfg. covering the costs of replacing the firearm.

http://glocktalk.com/forums/showthread.php?t=1474747

I think this one might be setback related....

Modified to add the link for the pull-down of the ammo from the box that was used...
http://10mm-firearms.com/factory-10mm-ammo/underwood-357sig-125gr-bonded-fmj-pull-down/msg12302/#msg12302

Intercooler · March 03 2013 08:40:05 AM MST

Darn shame all the way around. When the same platform gets these about every week it's hard to not say these things are related.

I'm not convinced striker fires are good for high pressure ammo. My XD has digested the screaming Underwood 9mm round without issues but others have seen problems in Glocks. Maybe it was a matter of time for me with the Springfield platform? Seems the old unsupported stock Glock barrels were an issue back when and they fixed it (for the most part). Then people are swapping to aftermarket barrels now and running into more issues. I don't know what to make of it but plan on getting real comfortable with shooting all my pistols with the Hatch Kevlar gloves I got for Christmas (highly suggest them!).

sqlbullet · March 03 2013 09:08:57 AM MST

Shadow, you might wanna stongly encourage those guys to get into 9X25. Then they can pursue laser velocities with a little more margine for safety.

Intercooler · March 03 2013 09:21:43 AM MST

As someone mentioned there what is the draw to the Sig round? I only see 125gr listed so why wouldn't you just do a 10mm?

4949shooter · March 03 2013 09:24:29 AM MST

Quote from: Intercooler on March 03 2013 08:40:05 AM MST
Darn shame all the way around. When the same platform gets these about every week it's hard to not say these things are related.

I'm not convinced striker fires are good for high pressure ammo. My XD has digested the screaming Underwood 9mm round without issues but others have seen problems in Glocks. Maybe it was a matter of time for me with the Springfield platform? Seems the old unsupported stock Glock barrels were an issue back when and they fixed it (for the most part). Then people are swapping to aftermarket barrels now and running into more issues. I don't know what to make of it but plan on getting real comfortable with shooting all my pistols with the Hatch Kevlar gloves I got for Christmas (highly suggest them!).

ICooler, do you have a link to those gloves?

Edit: I found them for $26.99 and $51.99. I don't know the difference, if any.

Intercooler · March 03 2013 09:50:58 AM MST

These are what I have and they fit like batting gloves but better. They breathe and feel like a second skin! No complaints here with quality, fit or function in my two times out with them and they aren't broken in yet.

http://www.amazon.com/Hatch-SGK100FR-Street-Kevlar-XX-Large/dp/B003X3NCTW/ref=sr_1_6?s=sporting-goods&ie=UTF8&qid=1362329205&sr=1-6&keywords=hatch+kevlar+gloves

The_Shadow · March 03 2013 09:52:15 AM MST

While I think this one may be related to possible setback with a round that is already in the upper pressure levels, I have been reading where some guys are seeing their factory and aftermarket captive RSA's, that drop out with takedown. This issue sort of bothers me, not having the pre-loading of the spring tension to maintain lockup, although I could be wrong... ${$default_huh_smiley}$

The 40S&W and 357Sig guns being the thinner/smaller platform also means thinner/smaller dimensions, i.e. thinner barrel & chambers. There are many things to consider...

The reason I actually purchased the 357Sig barrel was it was looking like a popular round, and I was getting some brass for it, to have another option in my arsenal. However the 9x25Dillon option was just to be different and unique. ${$default_cool_smiley}$

Intercooler · March 03 2013 09:54:57 AM MST

Not like a 22lb 1006 spring/rod. I have a nice dent in my door-frame where I let mine pop out one time. When the slide comes off now it gets pointed in a downward direction!

The_Shadow · March 03 2013 10:01:38 AM MST

Quote from: Intercooler on March 03 2013 09:54:57 AM MST
Not like a 22lb 1006 spring/rod. I have a nice dent in my door-frame where I let mine pop out one time. When the slide comes off now it gets pointed in a downward direction!

You got that right!

REDLINE · March 03 2013 10:02:29 AM MST

Can't say I'm surprised. After already noting Underwood's sloppy load practice in 10mm, I don't know why the same manufactuer's 357SIG loads would be any different. And certainly, setback could have added an extra measure of high pressure, but no one knows if setback was involved or not. Setback may not have been any of the issue, or it could have been the whole issue. We simply don't know the cause beyond speculation. I suspect in this specific incident we never will.

No question though, somewhere in mix was an issue.

Intercooler · March 03 2013 10:14:46 AM MST

Was it ever determined Kevin's loading varied more than acceptable level? I thought what we got for data showed it was within an acceptable tolerance?

It for sure can't equal Precision One's almost zero powder loading ${$default_shocked_smiley}$ Just the one being found is enough to tell me never buy it again! GAS Ammo is off the buy list too because data shows they may not even know what's on their ammo for bullets ${$default_shocked_smiley}$ ${$default_shocked_smiley}$

Intercooler · March 03 2013 10:56:52 AM MST

What other platform in .357 Sig has had Kaboom issues? I looked up the 229 and only found one which had a sketchy set of events. What I saw was a piece of brass way past the number of times it should have been reloaded. Another common thing it seems the shooter was doing was rapid-fire. I'm not a huge fan of that and never just cycle mine as fast as I can.

PBR offers some .357 Sig and looks like a Zero HP. Wonder what the powder is:

https://www.pbrammo.com/premium-line-357sig-125gr-jhp

Yondering · March 03 2013 12:23:24 PM MST

Quote from: The_Shadow on March 03 2013 09:52:15 AM MST
While I think this one may be related to possible setback with a round that is already in the upper pressure levels, I have been reading where some guys are seeing their factory and aftermarket captive RSA's, that drop out with takedown. This issue sort of bothers me, not having the pre-loading of the spring tension to maintain lockup, although I could be wrong... ${$default_huh_smiley}$

Shadow, that is completely normal for a Glock, and does not indicate that there's not spring preload in lockup. The rear end of the guide rod is only retained by the barrel during assembly; once it's together the guide rod is retained by the frame, not the barrel. It won't always grab that little lip on the barrel again during disassembly, but that doesn't indicate a problem.

EdMc · March 03 2013 12:41:26 PM MST

Quote from: Intercooler on March 03 2013 09:21:43 AM MST
As someone mentioned there what is the draw to the Sig round? I only see 125gr listed so why wouldn't you just do a 10mm?

For the same reasons the 40 cal was developed......lighter, smaller frame handgun, easier for some to shoot. At 125 gr it compares to 357 Mag velocities of the same weight bullet. Law enforcement groups using it have given favorable reports supposedly. Good penetration car doors etc, threat stopping ability and flat shooting. Interesting round, to me, I've got a M&P in 357 SIG.

REDLINE · March 03 2013 01:02:57 PM MST

Just in disections of Underwood's 10mm 135gr Nolser load we've seen the powder charge weight range of 800-X from 11.4 grains to 11.8 grains (after The_Shadow fired the 11.8gr load the primer fell right out of the case and the brass was smilied). In those same disected loads we've seen cartridge overall length range from 1.249" to 1.252".

That's a range of .5 grains of powder and .004" of COL.

When already loading to a target pressure of 37,000 PSI, my opinion is that the range we've seen is not acceptable. And we only disected a few rounds. More rounds disected would probably add to the range we already know is possible. Then there's the other group of threads where other's have pointed out deep smilies they've got with Underwood 10mm ammo that was considered by Underwood to be completely safe in the firearms they shot them from. Then there's UW 10mm 200gr XTP loads hitting 1300fps from ~4.5" barrels that shouldn't be happening at all. And there's at least the one recent KB mentioned earlier with an UW 357 SIG load.

Then there are other tear downs like I did showing the following variances;

UW 10mm 155gr Gold Dot = 1.249"-1.254", 10.5-10.7 grains
UW 10mm 180gr Gold Dot = 1.249"-1.262", 9.6-9.7 grains
UW 10mm 180gr XTP = 1.250"-1.252", 9.4-9.6 grains
UW 10mm 200gr XTP = 1.253"-1.258", 9.2-9.4 grains

( http://10mm-firearms.com/factory-10mm-ammo/finally-5-underwood-10mm-ammo-disections/100/ )

And this is just what I can think of off the top of my head. All in all you have to remember, we aren't talking about variances with midrange loads. We are talking about variances with top end loads. It makes a difference. Either way IMO the tolerance ranges leaving the UW factory are unacceptable. At least one KB, numberous heavy smilies, at least one primer falling out, and velocitites too high for SAAMI spec pressures prove it. And this is limited to what I can remember off the top of my head that we've simply seen and heard. What haven't we heard or seen?

Maybe it's simply that our opinions vary on what's safe and what isn't.