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Bad day at range. Blew up my 929


AzShooter

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First time I sent the Ammo to the powder manufacturer and they ran test and told me it was a detonation. They also bought me a new gun.

This time I'm still guessing but the gun is back at S&W and they will let me know what went wrong.

I'll report the findings when they tell me.

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Lots of crazy myths in the shooting world. Unfortunately, gunwriters sometimes buy in to the BS and then it really takes off. The internet does not help.

You still occasionally read that bobbing the hammer on a revolver can cause misfires.

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Am I the only one who considers the undercharge detonation thing an old wives tale? Hopefully someone who knows how to work a slide rule will chime in with science.

You're not the only one. Urban legend.

Talking about urban legends, I've heard of a guy who could get S&W triggers down to 4# reliably. Unfortunately I heard he doesn't take work anymore.

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Although it is comparing Apples to Oranges, I have dabbled in "Air Decking" using explosives. Which allows the operator to use less explosives to get the same effect.

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Am I the only one who considers the undercharge detonation thing an old wives tale? Hopefully someone who knows how to work a slide rule will chime in with science.

You're not the only one. Urban legend.
Talking about urban legends, I've heard of a guy who could get S&W triggers down to 4# reliably. Unfortunately I heard he doesn't take work anymore.

You're definitely not talking about me, Fish. I never recommended going below 5.5 to 6 lbs. Too mushy.

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1.18~1.19 on virgin JAG brass.

That's a load right on the jagged edge. As stated that's a + P loading. Get an extra .1 grains on a throw and you're over 40,000 PSI. .2 over and a hundredth short and you're close to 50,000. And JAG advertises as military spec which usually means lower case volume, which means even higher pressures.

Flying a little close to the sun with that one.

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A 627 using 38 short colt should handle 40000psi at the cylinder (rated for 357 magnum), the case would be the weak point.

BUT an N Frame 929 chambered for 9mm can't?

Both are N Frames and 9mm usually run in the 30000+psi range, it would be an assumption that they would both have similar maximum pressure tests.

N Frames have always been chambered for Magnum rounds in the past and could handle in excess of 40000psi.

Maybe Smith tried heat treating to a lower pressure max for a 9mm. And in the process got off the mark.

Curious.

Edited by pskys2
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A 627 using 38 short colt should handle 40000psi at the cylinder (rated for 357 magnum), the case would be the weak point.

BUT an N Frame 929 chambered for 9mm can't?

Both are N Frames and 9mm usually run in the 30000+psi range, it would be an assumption that they would both have similar maximum pressure tests.

N Frames have always been chambered for Magnum rounds in the past and could handle in excess of 40000psi.

Maybe Smith tried heat treating to a lower pressure max for a 9mm. And in the process got off the mark.

Curious.

I'm sure the frame would handle that and more. Now the titanium cylinder in the 929 is another matter. :devil:

Edited by Shadowrider
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A 627 using 38 short colt should handle 40000psi at the cylinder (rated for 357 magnum), the case would be the weak point.

BUT an N Frame 929 chambered for 9mm can't?

Both are N Frames and 9mm usually run in the 30000+psi range, it would be an assumption that they would both have similar maximum pressure tests.

N Frames have always been chambered for Magnum rounds in the past and could handle in excess of 40000psi.

Maybe Smith tried heat treating to a lower pressure max for a 9mm. And in the process got off the mark.

Curious.

I'm not saying that the 929 can't handle 40,000 PSI. I'd imagine they use a 50% safety factor, so they can probably handle around 50K, but with some wear & tear and potential long term damage.

What I was pointing out is that the load noted was close to max SAAMI + P specs. If the brass had a thicker head, that pushes pressures above SAAMI. And loading on a progressive, it's possible to get rounds with a slightly higher charge / lower OAL than targeted. So it's not out of the realm of possibility (or probability) that a load that is already above max spec in ideal circumstances gets pushed well above that pressure in practical circumstances. The smaller the case volume (i.e. 9mm vs a 38 special) the more slight changes in load are magnified.

For example, using a 165 Xtreme w 3.2 GR Titegroup (assume a heavier drop or slightly miscalibrated scale) at 1.180 OAL, QL shows 40K PSI. Assume the thicker brass reduces case volume by just 5% - that jacks pressure up a lot. As in, 10K PSI - up to 50,000 - probably close to the safety factor.

And while the frame may handle it, the cylinder of the 929 almost certainly has a lower tensile strength than steel N frame cylinders.

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I had a similar problem. One squib and one double charge. I changed my loading routine since this happened.

Yeah, I switched from my Dillon 550 to a 650 with the auto indexing I don't think this can happen again. Now I'm waiting for Smith&Wesson to let me know what they think.

I called today and they said they wouldn't get to it for at least two more weeks. They have a three week backlog. Now at least I know not to call for a while.

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I talked to S&W and when I explained how bad it was they told me not to bother sending in in.

Did they just send you a new one or what? :blink:

Since he accepted it was a reloading error that caused the KB I'm guessing it was more of a "sorry, no serviceable parts left to that".

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Smith & Wesson sent me a letter today saying they didn't find anything wrong with the manufacturing of the weapon. They did offer me a new gun at a discounted price, cheaper than I could get one off the internet.

Since I have all the accessories for the 929 I told them to send me a new one at the discounted price.

I got rid of all the ammo from my last batch, started loading on the 650 instead of the 550 and I'm hoping everything is now good to go. After the new gun comes in I'll do an action job, replace the firing pin with a longer one from APEX and one of their hammers.

Should be good to go after that.

Now lots of chronographing to get the right load.

Thanks everyone for your comments and concerns.

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