Chasing The Blown Up Taurus Mystery. Here Is What I Have Found So Far

[jonp]

Check the other thread to see pictures. On the theory which seems most plausible right now, I'm pulling ammo to see if I double charged a round causing the cylinder to blow up.

First was re-calibrating my GemPro 250 and checking the weights against a different scale. All good
I weighed all of the rounds and came up with a variation of 373.4gr-379.75gr. A double charge would have been 8.8gr which is about 2.5gr over this variation. That is 373.4gr + 9gr = 382.4gr
Checking random Starline brass yielded a difference of 2.3gr from the same supply I used to load these. The brass is part of a 1,000 rd order from Starline.
I then pulled the lightest and heaviest to test.
Boolits variation was 4.0gr lightest to heaviest weight.
Powder variation: .05gr Weight from 8.75gr-8.80gr

I checked the powder as suggested. I pulled out the last fast powder I used which is ETR7. I shook up the Unique then poured a healthy amount on a piece of white paper next to an amount of ETR7. Both powders appear very close in looks but the ETR7 is gray and the Unique black. There is enough difference to be easily apparent under light. The unique from the pulled rounds and the bottle are uniform black so no mixing.

OAL are all uniform. All primers well seated. I also tried 18grs Unique in a case allowing for a variation in the powder charge to 9gr and a double charge. The case is almost full as in a compressed charge would be needed to seat the boolit. It is so readily noticeable that you can see it under room light easily. Could I have still missed it? Maybe but unlikely since I was using a
Lee Single Stage requiring each charged brass to be lifted from the holder then the boolit to be seated by hand then loaded and crimped by hand one at a time. Several steps from inspecting under a light to loaded to catch a double charge.

So...where does this leave me? If you take a worst case scenario and use the lightest boolit, brass/primer you still come out 35% or so under a double charge. Could a boolit with a worst case scenario double charge using the lightest brass/boolit combination be picked at random from a case of 100 and blow up the gun? I guess but that seems far fetched as so far nothing indicates a double charge was in the rounds loaded and that random string of bad luck, a 1 in 100 bad boolit choice using worst case brass/boolits still being under the heaviest loaded round in weight is next to impossible to fathom.

Next step is to pick 12 at random from the remaining and get out my trusty Blackhawk and shoot them over a chronograph to see if there are any velocity spikes or strange readings.

[Der Gebirgsjager]

I've been following your threads with a great deal of interest. It seems to me that you are a handloader of lengthy experience, and I'd be more inclined to bet on a defect in the handgun. Unfortunately, as these things go, once the round is fired that does the deed the components are gone down range (or wherever they went!) and reconstruction is difficult. I did not see where the brass was recovered (?), and that could tell us a lot.
Also, something which hasn't received much comment, is the photos posted by others showing destroyed handguns of this type. That fact, that yours hasn't been the only one, makes me wonder about the soundness of the design. So much more weight in that lengthy cylinder to be turned and reliably locked up by the hand and bolt. Much more chance, I would think, of the cylinder chamber being not quite lined up with the forcing cone at the time of firing, or not being locked in place and moving with the fall of the hammer. Interesting that the barrel has broken away from the frame in some photos. Anyway, I think you should be commended for coming forward with this situation, and whether or not the problem is isolated and solved, users and prospective buyers can beware. Thanks.

[jonp]

The brass looks fine except for the lengthwise dent from banging off the cylinder. No cracks, splits, dents or holes. Looks like i could run it through a sizer and load it right back up. That is one of the reasons im doubting a double charge as the brass should be destroyed in that case id think

[KenH]

Jonb - I missed that in the original post with photos. You're saying the brass from the cylinder that blew apart still looks good? That is interesting.

I don't know anything about the Judge - but do the cylinder walls look any thinner than a normal pistol of that type? It almost seems like they designed the walls a tad too thin in trying to save weight?

[jonp]

One of the first things I did was look at the brass and primers. Yes, even the one from the blown up cylinder looks fine with no signs of over pressure.

[Preacher Jim]

I just went to local G.S.
Could not see any reason for that to happen now you say brass good still only thing could be obstruction in cylinder but said bullet hit target. you got a real head scratcher. That cylinder so long be like obstruction in barrel.

There is a definate bulge when I went back to main post cylinders are thin still think obstruction like I shotgun barrel only thing could have caused that to rupture as it did

[reddog81]

It's very odd that the brass is OK but the cylinder is torn apart. Is it possible a bullet was stuck in the cylinder throat when you fired off the round?

[Camper64]

According to the OP, not all target holes were confirmed after each shot so I don't think we can rule out barrel obstruction yet. I'm also glad know one was injured.

[Preacher Jim]

I look to that long cylinder and think obstruction in it would make the most since not barrel

[Lead pot]

I also have a Judge that I carry for a snake gun when I'm out with a metal detector. It's a great piece for quick close shots when needed.
This discussion made me look it over close to see if it has any noticeable bulges because I shoot it quite a bit but the main use is for the shot shell.
One thing that has not come up in this discussion is flashover detonation that will raise a pressure spike in a hurry. A light load is just as dangerous as a heavy load, sometimes more so. In the .45 colt case the load of unique used is small enough that the powder can lay level below the primer flash hole and this can cause a detonation instead of a progressive burn especially if by chance a mag primer got mixed by mistake this will cause a dangerous pressure spike. This is more common with reduced rifle loads then hand guns. But one can guess all they want what happened in this case and never find the answer. The only way to get a good analysis is send the parts to a lab for tests to find out if there is a flaw in the metal.

[JBinMN]

Just conjecture, but if the brass looked fine "after" this catastrophe, and it has been confirmed that the boolit/bullet impacted the intended target, then it is very likely it was a defect in the cylinder.

Hate to say it, but you will likely not find out anything more by yourself, since you apparently have "covered the bases" with checking the other ammo used, both by weight, checking charge possibilities liked mixed powder & firing in another firearm. Seems to me what is pretty much left is a failure in the cylinder either by composition, or a "stress fracture" that was unnoticed, or something else going back to the firearm itself.

I am very happy, as I am sure you are, that it was something that happened without injury the way you have described it, and I hope it never happens to ya again.

I have owned & still own Taurus firearms & have no issues with getting a good response from them when I called about something I needed to know. I am aware that the use of cast boolits & reloads voids their warranty, but I still do what I do because I do not hold them responsible for things that are not under their control, like the possibility that I, or someone else, does something wrong. Those who do not like them, so be it. I happen to like mine, along with the other makers of the firearms I own, I understand that there can be a "lemon" occasionally. by "any" maker of a product. ( Lymans recall of muzzleloaders recently, comes to mind) Which, BTW, is why I will not buy or fire a firearm without inspecting it myself, "in hand". I do not care to handle, or have, a "pig in a poke"...

So, IMO, YMMV with any product ya buy & when I see folks posting immediately that it is the maker of the firearm that is the cause of an issue, simply because they do not think highly of that maker, I take such comments with a grain of salt. Sometimes it is not the maker, but something else that caused the issue. I guess it depends on if one is one of those "Chevy vs Ford/whatever" types of people, when others are, " I just want it to be affordable & get me there while I enjoy the ride" type folks. Takes all kinds, I guess...

Anyway...

G'Luck! if ya investigate further! If ya do decide to send it in to Taurus, even if they will not do anything to replace it, perhaps they will at least provide an answer about the condition of the firearm & the likely cause.

Please share if ya do send it in & they give ya some sort of an answer. That would be nice to see how it works out & if the mystery gets a solution.
:)

[Jniedbalski]

If the brass didint explode from a double charge forcing the cylinder to blow apart it must be bad heat treat or metal in the cylinder. If the brass is still all together I do not see how it could be over loaded. The cylinder walls in the photo lookvVery thin I guess to save on waight. My be the brass would never show signs of over pressure if the cylinder was that thin. Don’t know

[jonp]

I have a Taurus 1911 that is a fine gun so I have no bias against Taurus in that respect. I'm trying to cover the "bases" and after running some of the rounds through my Blackhawk I pretty much have covered everything I can think of.

Just because the other rounds are fine does not mean one was overcharged or defective. It could have happened. After the inspection of the gun and brass not to mention everything else I've looked at I'm increasingly suspect of the cylinder of the Judge having a manu defect of some sort.

[dubber123]

If the brass didint explode from a double charge forcing the cylinder to blow apart it must be bad heat treat or metal in the cylinder. If the brass is still all together I do not see how it could be over loaded. The cylinder walls in the photo lookvVery thin I guess to save on waight. My be the brass would never show signs of over pressure if the cylinder was that thin. Don’t know

If you recovered ALL of the brass, and none of it was burst, I personally would rule out an overcharge. I cant say I have EVER seen a blown cylinder where the round that caused the failure was intact. Cases are WEAK, and don't require much to let go if unsupported. If ALL the brass is intact and in good shape, you had a metallurgical failure of the cylinder. I would guess overly hard, and lacking the elasticity required. EVEN if your load produced 17K Psi, which I doubt with the tolerances and huge free bore, that's not a lot of pressure. My S&W snubs are probably as thin or thinner, and have digested a lot of rounds in excess of that figure. If the brass survived, the gun failed in my opinion.

[243winxb]

Stainless steel cylinder was not heat treated correctly.

If you were firing 410 shot shells at the same outing, the plastic has been know to separate and stay in the cylinder.

If you had a tube of plastic ahead of the 45 colt chamber, it may raise pressures a lot.

But you did say all brass was normal, with no pressure signs??

[white eagle]

seems to me that if you are that close to max on your charge weight
that you need to worry about components weight you are most likely
treading very close to dangerous pressures already now if it has nothing to do with
you,your loads or components that only leaves one thing, the gun itself

[arlon]

I thought I read in the first post that the case left a perfect "45 LC" imprint of the roll stamp on the frame? If it left an imprint on the frame it had to have had some pressure behind it. Maybe a combination of issues added up rather than a single cause.

[Rcmaveric]

Interesting. I will side with others on if the brass was still that makes the double charge less likely. I still love my Taurus fire arms but investigation of the judge fire arms may be in order to see if there is trend.

[10-x]

Sure looks like taurus has a problem. Wife has the TCP .380 but I wont buy any of their revolvers. Way back when they started selling in the US they had problems. Saw quite a few in the range, no LEOs I knew would buy one. Heard their QC improved but this is not the only taurus incident Ive heard of lately. Pretty sad as their revolvers look pretty good.

[jonp]

I thought I read in the first post that the case left a perfect "45 LC" imprint of the roll stamp on the frame? If it left an imprint on the frame it had to have had some pressure behind it. Maybe a combination of issues added up rather than a single cause.

You read that correct. You can read "45LC" perfectly on the frame with the rim clearly marked. Perfect casehead.

[HangFireW8]

Well there definitely was a metallurgical failure. Question is, did it occur within acceptable pressures or not?

I've seen headstamps mirrored on bolt faces before on new guns. It is due to the high pressure. 17K is not going to make that happen.

So now we know that there was very excessive pressure. There are many causal possibilities already listed in this thread. Which one(s)?

[BeeMan]

Jon,

Looking at pics on the original post and re-reading the thread prompts a few questions.

First, is there a bit of smoking in what used to be the front part of the 45 Colt part of the chamber? There seems to be a definite color change, difference in finish, or residue between what looks like the forward end of the 45 brass and the 410 portion of the chambers.

Second, it looks like this portion of the cylinder near this difference was plastically deformed more than anywhere else. Is that perception correct?

Third, it's been a while since I looked at a Judge. Where are the bolt stop notches in the cylinder?

Next, are there any gas cutting or smoke marks that might indicate where the rupture in the cylinder first started?

Last, do you know or recall the chamber dimensions in the 45 Colt vs 410 section of the bore? Was it a straight through bored cylinder or was there some dimensional change that could have created a local stress concentration?

BeeMan

[243winxb]

Judge 45/410
Separation of the shot shell is caused by the chamber from the 45 colt. The 45 brass body is larger in diameter than the 410. Some jb bore paste should polish the sharp edges out. Look up the chamber drawings for the 45 & 410. You will see the difference in diameter & chamber. The chamber for the 45 runs into the 410 chamber. The 410 being smaller in diameter then the 45 brass. The 410 chamber then becomes the "throat" for the 45. But the "throat" is much larger than a standard 45 throat. The 45 bullet will rattle down the oversize throat on firing, resulting in poor accuracy. Sorry.

See SAAMI

[Mytmousemalibu]

Just curious, is the firing pin indention on that primer perfectly centered? Or does it seem to be offset any?

[BeeMan]

Thank you 243winxb. I've not had a chance to look into the chamber dimensions but had a hunch based on the pictures. The design sounds like a perfect storm to not seal the brass case necks due to low pressure, followed by a chance for the bullet to get sideways and jam.

Result could very well be a bore obstruction with partly burnt powder, which partly consumed any deterrent coating and reduced particle size. Powder then starts to burn again but at a more progressive rate. Add a sharp corner at the 45 to 410 chamber transition to concentrate stress. Sounds like a poorly thought out design, possibly made worse by a different dynamic response of a reload relative to a factory load. This behavior happens in certain rifle chambers with slow powders and long bullets when the throats get firecracked.

This is all speculation of course, but without all the parts in hand and a proper analysis it could be a reasonable explanation.

[smoked turkey]

I have read this thread with much interest as I am sure others have also. I do not have a Judge, but the comments about the diameters of the 45/410 being different in this type of firearm as well as the comment about a poorly thought out design prompts me to ask if anyone has read or heard of problems with the Smith & Wesson Governor which appears to be of the same type of firearm and design as the Judge. Just seems that if it were a problem in the Judge, one would think that the Governor would also have some of the same failure situations. Not trying to high-jack the thread but wondering about the Smith?

[starmac]

Does the judge have a bigger percentage of failures than other handguns?

[jonp]

Just curious, is the firing pin indention on that primer perfectly centered? Or does it seem to be offset any?

All appear centered and normal. No runs, craters, pinholes etc... Just average indentations.

[243winxb]

Heat treating of the cylinder, is my best guess.

There was a recall on stainless, Tikka T3 and Sako years ago, 2004, because of a heat treating issue.

[35remington]

If you have intact brass that was fired in the blown up cylinder with a hammer strike that has unenlarged primer pockets you can rule out “flashover detonation” and other such fairy dust theories.

The reason “flashover detonation” in invalid as a blow up theory is that powder strung horizontally along the case exposes less of the powder to the primer’s flash, not more of it.

People that posit these theories have not logically thought about it nor tested the premise to see if it has validity. It is simply repeated because they read it somewhere.

It is easily discredited.

[jonp]

I have the brass as stated before and the one from the cylinder that split open ie: the one the round exploded in. Brass looks fine as does the primer. No splits or cracks

[pete501]

Will Taurus replace your gun. I have sent back and received in return, a couple of PT-22's. (Both developed a crack in the slides different locations). Each time a new pistol with the same original serial was returned to me directly.

[JBinMN]

Will Taurus replace your gun. I have sent back and received in return, a couple of PT-22's. (Both developed a crack in the slides different locations). Each time a new pistol with the same original serial was returned to me directly.

Not likely if they are told it was with reloads. Reloads void their warranty.

[jonp]

Der Gebirgsjager: Much more chance, I would think, of the cylinder chamber being not quite lined up with the forcing cone at the time of firing, or not being locked in place and moving with the fall of the hammer.

Upon further inspection of the primer for the round that was in the chamber that blew up the gun, the firing pin strike is slightly off center. Of all of the fired brass from this batch including the other 3 fired before the fateful round in the Taurus Judge when it blew up none of the others are off center.

We have a winner and this is why I came to this site for help in finding an answer. The working theory is a sticky cylinder stop causing the cylinder to rotate slightly off center when the trigger was pulled on a freely rotating cylinder not in line = BOOM

Here is a thread on just this problem in Taurus Armed http://www.taurusarmed.net/forums/smithing/119610-taurus-revolver-issue-fix-sticky-cylinder-stop-derailing-cylinder.html

[dverna]

Jonp,

Make Taurus aware of both your threads here and the one on Taurus Armed. They negate blaming the ammunition.

BTW I commend how you approached this issue...Very well done!!

[jonp]

The guys on this site are the best in the business and have years more experience than I do which is why I came here with this. I had to recheck the primers under a bright light with a magnifying glass to catch the off center strike. Once I saw it, it was obvious of course. Ugh...

I'm very interested now in finding that top strap to see if the boolit deflected up and broke it off.

[starmac]

I thought the boolit hit the target?

[243winxb]

Neck tension with the new unfired brass.
When you pulled the bullets of the loaded rounds, did it take a lot of effort?
If the firing of the primer moved the bullet to soon, there may have been a secondary pressure spike?


The off center pin strike, cylinder not locked, should have sheared lead at the forcing cone/barrel, if a swc bullet? Even if the bullet made contact with the frame, the 16,000 PSI has plenty of slop in the cylinders throat to relieve it.

We may never know.

[jonp]

I thought the boolit hit the target?

Crud...your right. I'm sure there were 4 holes and 4 fired. Now I'm going out to check the target to make sure the holes are all the same and I didn't put up a "slightly used" target. I was a little err....hyped up when I checked last time.

All were SWC Lead. I'm going back to look at the cone with the light and glass again.

[jonp]

There is lead jammed between the barrel shroud and the forcing come with the cone moved slightly off center.
Here is a picture of the brass that was in the cylinder. So....just enough off center to shave the boolit off center with a split second holdup causing enough back pressure to blow up cylinder and force the boolit down the barrel? The brass is not split so the pressure spike was in front of the brass not in it? The cylinder bulge is right at the mouth of the case and in front not at the case itself indicating the cylinder held at that point.
Any ideas?
217082

[mold maker]

Shuck's heck and darn, the attachment won't open.

[Omega]

Definately send these photos to Taurus, they may just surprise you.

[243winxb]

Post 40.
Cylinder timing problem. High pressure when the bullet made contact with the frame/barrel.

Unique does contain Nitroglycerin. This may cause detonation under some conditions.

Both ends of the cylinder were blocked just enough time to do the damage.

[35remington]

Ah, the “detonation”thing again. No accredited ballistician finds that credible with powders like Unique, and in my time, and with the Hornady plant so near, I have talked to more than a few.

The mysterious “d” word gets invoked when more prosaic causes for events get ignored.

A cartridge off center enough to be struck mostly centered on the primer will see the bullet mostly centered in the forcing cone. Since the forcing cone is in fact a cone, even such an slightly off center strike will see the bullet go down the barrel safely. The reduced diameter front of the bullet also provides alignment.

Off center does not seem plausible as a cause. Need to look elsewhere as that makes poor sense.

Jonp said the case was intact. Even if Unique or whatever powder was used could “detonate” it certainly did not here.

[35remington]

In addition, the only way the gun can fire is with the locking bolt in the cylinder notch. If anyone can make the hammer fall on any revolver they have when the locking bolt is not in the notch that is the first I have ever heard of.

I doubt this revolver is the exception. When the locking bolt is in the cylinder notch the cylinder really cannot be substantially misaligned with the forcing cone. The locking bolt stays in the notch throughout the firing event. Due to forces involved since it starts out with the bolt in the cylinder notch (or the gun won’t fire in the first place) the bolt stays in the notch throughout the firing event. Physics says so.

[Tackleberry41]

Im gonna toss out a theory that its just a marginal design. We have to remember Taurus makes these 45/410 chambers for the US market. In brazil, they sell them as 410 only. So a 410 will never see anything over that 12k pressure limit. So they design a gun for that use and no more. Now if Taurus was a better company, like Ruger lets say, they might overbuild the gun a bit. But I have not seen where guns in Brazil are made that well. If they can cut a corner...they will.

So maybe Taurus takes that same basic gun thats fine w 12k psi 410 shells. Then they ream them out to 45 colt, which reduces the cyl wall thickness. A company like Ruger would compensate, Im thinkin Taurus might not. 45 colt is already past that limit to begin with. Then you have that screwy chamber where yes a bullet can end up side ways, but still be forced thru the barrel. Lets imagine how that pressure wave would be, lets say its 14k, then bullet goes that inch or so of freebore, then wham is forced somewhat sideways into the barrel. One could imagine the pressure is gonna spike, and no where to go. Does Taurus even bother to proof test anything?

Proper metals = more money.
Better heat treatment = more money.

Not seen anything about the S&W governor blowing up with the same ammo in them. But S&W is a considerable jump in price and S&W will over build.

[jonp]

In addition, the only way the gun can fire is with the locking bolt in the cylinder notch. If anyone can make the hammer fall on any revolver they have when the locking bolt is not in the notch that is the first I have ever heard of.

I doubt this revolver is the exception. When the locking bolt is in the cylinder notch the cylinder really cannot be substantially misaligned with the forcing cone. The locking bolt stays in the notch throughout the firing event. Due to forces involved since it starts out with the bolt in the cylinder notch (or the gun won’t fire in the first place) the bolt stays in the notch throughout the firing event. Physics says so.

OK, I'll buy that. Let's move on to something different then.

[243winxb]

The explosive power of smokeless powder is extremely dangerous when confined to a small container. In addition, certain smokeless powders with a high-nitroglycerine concentration can be induced to detonate.
http://www.firearmsid.com/Feature Articles/McCord_gunpowder/

[35remington]

That would be relevant if the conditions for “detonation” existed in the chamber of a firearm when a normal charge of powder was used. It does not.

The idea of “detonation” is that faster smokeless powder somehow explodes like dynamite every once in a while for utterly unexplainable reasons while somehow for the millions of other rounds that are fired under identical conditions it somehow does not.

Trouble is, each and every time these events have been subject to forensic analysis that can answer the question definitively simple higher than standard pressure was involved or some defect in the gun was present.

If someone can talk about a blowup without getting into the weirder theories it better helps to solve the problem.

Besides, jon’s case was intact. Even if you believe in unicorn detonation theories......nothing “detonated” here.

[243winxb]

In addition, the only way the gun can fire is with the locking bolt in the cylinder notch. If anyone can make the hammer fall on any revolver they have when the locking bolt is not in the notch that is the first I have ever heard of.
.

You need to read the old model Ruger Blackhawk instruction available on Rugers website.

Its very possible for the firing pin to hit off center of the primer. The cylinder is out of time and not locked.

Single actions need to be loaded a certain way.

Happened to me with a 44 mag, but luckly, the round didn't fire.

[smilie=s:

[35remington]

This gun under discussion is not a single action firearm. According to the owner it was in a good state of repair.

The off center bullet so obstructed by misalignment that it hit the frame is not plausible. The essentially predominantly centered firing pin strike also attests to that.

Very slightly off center, which is the most it could have been, will blow up nothing.

[funnyjim014]

Could the remaining parts be tested for hardness? No one seems to have mentioned anything more than just saying it's got to be bad

[35remington]

What round count has the revolver been exposed to?

[DCP]

That would be relevant if the conditions for “detonation” existed in the chamber of a firearm when a normal charge of powder was used. It does not.

The idea of “detonation” is that faster smokeless powder somehow explodes like dynamite every once in a while for utterly unexplainable reasons while somehow for the millions of other rounds that are fired under identical conditions it somehow does not.

Trouble is, each and every time these events have been subject to forensic analysis that can answer the question definitively simple higher than standard pressure was involved or some defect in the gun was present.

If someone can talk about a blowup without getting into the weirder theories it better helps to solve the problem.

Besides, jon’s case was intact. Even if you believe in unicorn detonation theories......nothing “detonated” here.

You're so close! S.E.E does not happen with fast burning powder. Only slow burning. I shoot a lot of gallery loads 3 to 4 grains of 700x even with a double charge there is not enough pressure to blow up your gun. I also called Lyman loading lab and talked to a tech to confirm this.

[kens]

I read that the case headstamp was impressed in the frame? This would indicate high pressure.
What does the headstamp of the case look like?
Is it smeared?

[BeeMan]

I am keeping additional comments in this thread, though it responds in part to information added to the other thread.

After reviewing SAAMI drawings, I am still staying with the primary cause as poor design but also adding that this failure is probably a due to a combination of factors. This turns out to be the case more often than not when I do root cause analysis on product and process failures.

Just because something can be done doesn't mean you should. Reaming out a 410 revolver cylinder to also chamber a 45 Colt is only advisable if the design is evaluated for the old chamber, the new chamber, and the interactions of the old and new. Minimum and maximum dimensions allowed per SAAMI for each clambering can go from a conclusion of 'looks okay' to 'warning bells are going off.' As a single dimension's example, the maximum diameter allowed at the front of the 410 SAAMI chamber can allow an off center impact on the barrel forcing cone if the bullet is off center. Statistically speaking, an off center impact is a matter of when, not if. One impact, in and of itself, may not be a problem. But rarely is a single factor out of spec in complete isolation.

Unless we can review design intent from the chamber reamer drawing and look at the as machined dimensions of the part that failed, there is too much room for tolerance stack to convince me that the cylinder design was not vulnerable from the beginning.

The questions about rotational mis-alignment due to bolt locking issues struck me the same as 35remington. Misalignment to a small degree is a given. More than one source said Colt revolvers locked up tighter than most, but that they also wore and required a smith's attention to stay tight. Forcing cones are the insurance for this characteristic of revolver design.

The question of hardness has been raised. The part does not look brittle to me in pictures. I would suspect it being soft if anything, and then unzipping once it initially failed at a stress riser or internal material defect.

Another question comes to mind: what was the bullet profile, size, and hardness? Roundnose, SWC, .452, .454, etc. The OP acknowledged a mix of purchased and cast lead, if I recall correctly. Which was in the chamber at the time? Probably small considerations and maybe not a factor at all. Hints can come from asking and answering all the questions though.

As far as the load pressure goes, I would de-emphasize the load pressure as a primary concern. The bore diameter ahead of the brass case likely allowed considerable blowby, based on SAAMI specs.

Last, as a matter of analysis, the question needs to be asked whether lead around the barrel interface is a cause of the event or a result of the event. Once parts started deforming, alignment was almost certainly out of spec so lead could have been deposited there because of misalignment. This all happens very fast but there are still ways to reconstruct the sequence.

BeeMan

[JBinMN]

I am no expert, but this pic from jonp( the OP) would not make me think it was a S.E.E..

http://castboolits.gunloads.com/attachment.php?attachmentid=217082&d=1522009945&thumb=1

I am gonna stick with my opinion that it was failure of the firearm due to faulty manufacture practice(s) until someone can provide more evidence otherwise.

BTW, in no way would I reload that case, as it was described to be in an earlier post.
IMO, That one is one for the wall or the recycler... Your choice though.
;)

[243winxb]

For outside pressure to crush the case , the bullet made a stop before entering the forcing cone. Pressure spike. It also happens when the bullet moves out of the case to soon, from the firing of the primer. It sort of acts like a plugged barrel.

In a revolver, bullet jump is possible with light neck tension. The bullet moves forward, out of the case. Most times it keeps the cylinder from turning.

The recoil from thr OPs first 3 shots may have disloged the forth rounds bullet? With the 410 chamber length, its not going to keep the cylinder from turning.

[DougGuy]

I am going to attribute this KB to an obstruction in the cylinder itself. Somehow a boolit lodged in the cylinder, as in a squib load that may have enough felt recoil to not alarm the shooter, yet left a boolit in the cylinder. I don't think there was a double charge or even an overcharge of Unique. However, I often caution about using more than 10.0gr of Unique in 45 Colt caliber because it can be spiky and unpredictable. Even under the overcharge scenario, I don't think the gun would have been damaged like it was so I am going with an obstruction in the cylinder.

[edp2k]

Possible inclusion in the cylinder metal.

[jonp]

Doug: the bullet in cylinder is good except these were the first from a clean gun.