"73 Uberti Blow Up

[August]

It's always good to read about safety issues on a forum.  It keeps us on our toes.

Not yet mentioned in this discussion is the common problem of sticking firing pins on '73 rifles.  A firing pin that is stuck (bound) in the forward position can, and eventually will, set off a round as the gun is levered.  Visualize the firing pin being proud of the bolt face and coming forward onto the round laying in the elevator.  The round could discharge at any point while moving forward, to battery.

This is not a theory, it has happened to me.  The round (a 38/40 180 grain bullet, case filled with Shutzen FFF) went off early in the levering of the gun -- about the time the bullet started entering the chamber.  All but the back 1/4" of the case was turned to shrapnel.  The lever was bent significantly.

The firing pin getting stuck this way was the result of repeated dry firing without a snap-cap in the gun.  The firing pin peened a burr into one of the narrow parts of the channel and that burr locked the firing pin solid in the bolt.  (the mechanism is inertial on Uberti rifles and the only thing stopping the forward movement of the pin on a empty chamber is the shoulders of the narrowed channel in the bolt)  I subsequently learned that this is a common issue from the 'smith who had repaired several '73 rifles that had "blown up" over the years.  He said, in every case, the rifle was owned by a serious shooter who had done a lot of dry firing with it.

He went on to tell me that REGULARLY testing the firing pin for smooth and uninterrupted retraction, back into the bolt, was a standard test that every '73 owner ought perform during every cleaning episode.  I have done so ever since.  Up, until that time, I had never checked the firing pin for binding, I dry fired a lot, and never used snap caps.  Those three things have changed.

I got off without hurting any other shooters and felt very fortunate.  The gun had to be completely rebuilt, but I got a BIG lesson for my money.  Hope this lesson helps keep you safe.

[Chance]

I do know of several folks whom have managed to stuff two 250Gr bullets in a 45 Colt case. 

This statement fascinated me so I thought I would set out to intentionally duplicate it. Using a Lee 0.5cc dipper I put some sand into a .45 Colt case and pressed in two 255 grain bullets (250 grain not available). Picking up the cartridge it was immediately obvious that it was heavier than it should be (OK, the sand would be a shade heavier than powder). It would also have stood proud of the others in a box as the resulting cartridge had an overall length of 1.75". To get those two bullets into that case there would apparently have to be no powder in there at all.

Chance

[PJ Hardtack]

August - thanks for the tip! I'll pass it along.

This theory makes more sense to me than any of the others.

[Trailrider]

Alright, Ladies & Gents...grab a cup of you favorite beverage, be seated and get comfortable. (There may be a quiz at the end of the lecture period).
First, I will agree that without seeing the rifle in question, analysis of the problem is difficult.  An OOB firing sound possible if not probable.  The original Winchester '73's design was far superior to the current batch of reproductions.  Slam fire due to inadvertent release of the follower on M1860-design Henry Repeating Rifles has definitely happened! My solution is to load with the rifle almost horizontal, and to firmly wrap the fingers of the other hand around the barrel/magazine prior to releasing the follower.

Now, as to "detonations":  By ordnance definitions, a "detonation" is an explosion that produces a shock front in excess of 25,000 ft/sec. There is insufficient chemical energy in small arms smokeless powder to cause a "detonation"!  HOWEVER...in smokeless powder bottleneck cartridges, especially ones that have sharp shoulders and are overbore capacity, reduced loads of slowburning smokeless powder can cause overpressure conditions strong enough to exceed the ultimate tensile strength of the brass cartridge, thus releasing high pressure gas into the action, with bad results! What causes the high pressure with reduced loads of slowburning powder is creation of a shock wave that, if the powder is in a certain configuration in the case, can reflect off the front of the shoulder in the case. When such a shock wave reaches the smoldering or partially burned powder, the pressure increases, which, in turn, increases the burning rate of the power. This increases the pressure, which increases the burning rate exponentially until the cartridge ruptures. This phenomenon has been known by Naval Ordnance engineers since at least the 1960's and probably before.
Moral: DO NOT ATTEMPT TO REDUCE LOADS OF SLOW-BURNING POWDERS BELOW THE RECOMMENDED CHARGES!  If you want reduced loads, go to a faster-burning powder!

Revolver blowups:  There are three potentials for overpressures in revolvers: 1) Double-bulleting due to failure to notice what's happening either by the handloader not paying attention to what he/she is doing; or malfunctioning of a progressive loader. (I have never had the latter happen...because I don't use a progressive press!)
2) Double-charging of a smokeless powder, either through carelessness or malfunctions.  However, experiments have shown that some double charges may not result in destruction of the gun!  Just be careful!
3) A phenomenon of premature shotstart in revolvers, where the bullet moves out of the case, and into the forcing cone where the bullet stops, allowing the pressure to build up until the case ruptures, allowing high pressure gas to do a number on the gun!
Now smokeless powder requires between 5,000-7,000 psi (NOT CUP!) to commence stable burning. If the bullet starts to move before this pressure level has been reached, the pressure will drop until the remaining powder is smoldering, but no extinguished. If the bullet lodges in the forcing cone and stops, so that the barrel-cylinder gap is blocked, the pressures will rise. This will cause the burning rate of the powder to increase, increasing the pressure, etc., exponentially.  Depending on how sloppy the chamber is compared to the cartridge case prior to firing, the increasing pressure will expand the case until it ruptures, releasing hot gases that act like a cutting torch on the steel of the chamber wall. With many .45 LC guns, the oversized chambers allow the cartridge to initially lie against the bottom of the chamber. If the bullet stops in the forcing cone, as outlined above, the case will usually stretch upward until it ruptures at the 3 o'clock and 9 o'clock positions, releasing the flame and cutting the chamber walls. The pressure also causes the top of the cylinder to come off, usually taking the topstrap with it.  Experiments I ran some years ago, measuring pressure-time curves in .45 LC ammo, purposely loaded to allow premature shotstart, without causing destruction, as well as experiments by others, confirm the presents of the pressure spikes and drop off until the bullet hits the forcing cone.
There is a simple way to prevent this phenomenon: Insure that "bullet pull", the force needed to move the bullet out of the case is high enough so the powder gets burning fully enough to move the bullet: Reduce the diameter of the expander plug sufficiently so there is good friction between the case wall and the bullet; AND CRIMP, CRIMP, CRIMP! Roll crimp the case mouth into a crimp groove enough so you can see and feel it, but not so much as to collapse the case or bulge the case wall away from the side of the bullet!
Now, I will entertain questions until the end of the class period. Go ahead! Flame away! 

[Dave T]

I have to support everything Coffinmaker and Trailrider have said. While reading this I tried to remember how many "blow ups" I've been present for. It's well over half a dozen in 50+ years of shooting and competition. In every instance I saw or heard about it was eventually determined to be a reloading error. Double charges in progressives that don't auto advance, changing powder type without resetting the measure, and just not paying attention (watching TV while reloading is a classic).

Dave

[PJ Hardtack]

I've witnessed two catastrophic blowups with Henrys - three rds in each case. In both, it was the shooter who caused the failures by letting the follower drop on loaded rds.

In the case of the '73 that is the topic of this question, the shooter did have one other loud sounding report on a previous stage that attracted attention. It was his first rd on the next stage where the failure occurred.

[greyhawk]

It's always good to read about safety issues on a forum.  It keeps us on our toes.

Not yet mentioned in this discussion is the common problem of sticking firing pins on '73 rifles.  A firing pin that is stuck (bound) in the forward position can, and eventually will, set off a round as the gun is levered.  Visualize the firing pin being proud of the bolt face and coming forward onto the round laying in the elevator.  The round could discharge at any point while moving forward, to battery.

This is not a theory, it has happened to me.  The round (a 38/40 180 grain bullet, case filled with Shutzen FFF) went off early in the levering of the gun -- about the time the bullet started entering the chamber.  All but the back 1/4" of the case was turned to shrapnel.  The lever was bent significantly.

The firing pin getting stuck this way was the result of repeated dry firing without a snap-cap in the gun.  The firing pin peened a burr into one of the narrow parts of the channel and that burr locked the firing pin solid in the bolt.  (the mechanism is inertial on Uberti rifles and the only thing stopping the forward movement of the pin on a empty chamber is the shoulders of the narrowed channel in the bolt)  I subsequently learned that this is a common issue from the 'smith who had repaired several '73 rifles that had "blown up" over the years.  He said, in every case, the rifle was owned by a serious shooter who had done a lot of dry firing with it.

He went on to tell me that REGULARLY testing the firing pin for smooth and uninterrupted retraction, back into the bolt, was a standard test that every '73 owner ought perform during every cleaning episode.  I have done so ever since.  Up, until that time, I had never checked the firing pin for binding, I dry fired a lot, and never used snap caps.  Those three things have changed.

I got off without hurting any other shooters and felt very fortunate.  The gun had to be completely rebuilt, but I got a BIG lesson for my money.  Hope this lesson helps keep you safe.

This is outta place here proly shoulda put it in the 92 place but its on subject - an OOB with a Rossi 92 - however maybe a lesson for someone
Close to 40 years ago a mate of mine bought this Rossi after the deed was done - it had been traded to Myras gunshop in the outback town of Broken Hill - potential buyer comes in and some fool decides to test cycle it with live 357 mag round in the shop - kaboom!!!! boolit exits stage left and high leaving a nice lil souvenier hole in the window that I was told still there 20 years hence. Boolit clears the other side of main street and likely came to rest in someones chook pen on the outskirts of town - aside from the brown underwear no harm done. So my mate buys this work in progress cheap for me to fix  (we did a lot of that) story was a broken firing pin - it seemed to be ok but after one untimely discharge I pulled it down to discover a winchester original firing pin replaced the Rossi but the gunshop dude had lost the ejector assembly and we also missing the front barrel band (carbine) -- I made a new barrel band /front sight and ejector assembly, fitted the firing pin - I did a lot of testing and eventually put the Rossi in my rack as a finished deal (sold now) years went by and I had a friend rebarrel a original 44/40 for me - I stripped it out before he got it and everything was fine and it went back together sweet - - he did the job, test fired it - I shot it on and off for a year or so - only a couple hundred rounds - one day I was cranking it a bit practicing for a rapid fire match and had an accidental discharge (gun went off on target but finger clear of the trigger, it just fired as the bolt closed)  ---ooooops -- a broken firing pin - when I pulled it down was plain the pin had been broken quite a while but still working (could tell that by the peening impact where the break was) and it was also bowed a little to the right hand side - not much - the break was captive between the cheeks of the lever - after some head scratching I visited my gunsmith mate who just happened to be woking on another 92 (one of several he aseembled from parts he was given) we sat and talked while he worked and I watched him assemble the new gun - came to fitting the lever pin and ejector and hes picked up a hammer and pin punch with the lever pin about halfway home - couple of taps - didnt seem like a lot the pin moves some then goes home ok ---whats the point ? ok right when he picked up the hammer to tap that pin it was sitting interference on the weakest point of the firing pin - its bowed it a little bit sideways and probably upwards as well and I reckon his hammer and punch trick has broken the pin in my 44/40 and someone else had done the same trick with same result on that Rossi  - it all works while ever the front part of the broken pin stays free in the bolt but as soon as the peening of the break gets enough swelling to bind (in the lever in a 92) and then we add some impact with a fast close of the bolt ----off she goes ----- its a theory anyway !!!   

[Chance]

Regarding the OP - do we know if the bullet exited the barrel? Is the brass cartridge case available for examination?

Chance

[PJ Hardtack]

Chance

I haven't spoken to the person that suffered the blow up since the incident as he went back to work out of town. I will ask someone who examined the rifle if the bullet left the barrel.

Greyhawk

Looks no design is immune mechanical failure, compounded by human error. It's 'heads up' all the time.

When I acquired my first paper Sharps, I was told that I had a potential bomb on my hands as the next rd could be ignited by a smouldering piece of paper left in the chamber.

As a result, I've made a habit of giving the chamber a quick blow before inserting the next rd. There is occasionally a narrow strip of paper left where the glue was applied, but it has never been an issue.

I've also never read any historic accounts where it was a problem during combat.

[Lumpy Grits]

Are 'we' certain, that this didn't happen after a squib?
LG

[Coffinmaker]

Let us go back a ways.  Turn the pages back and re-read if you will.  Between what Trailrider and Wrote, I would hope there is at least a glimmer of the science and physics involved.  If all I and trail rider accomplish is to extinguish a couple of "Old Wives Tails" we sill have accomplished a lot.  Altogether too many people are PARROTS.  Willing to grasp what amounts to a Guess and Gossip and begin to repeat it as gospel.  That is a shame.

In this particular instance, we can only offer a WAG (Military Acronym for a Wild Ass Guess).  None of us were there, none of us had a chance to look at the rifle IMMEDIATELY after the incident and before anyone Gould go finger poking and destroy the forensic evidence.  Leaves us with with a simple BANG.  Big loud BANG perhaps.  Then an exclamation form the shooter.  And now at this point, we can't actually make a real good guess.  There are lots of possible causes.  Here is the bottom line.  Someone has a busted rifle.  that someone has no clue why.  Nor do we.  Been some real good discussion.  But now it's becoming an expired Equine.

[PJ Hardtack]

Are 'we' certain, that this didn't happen after a squib?
LG

It was the first rd he fired at the beginning of a stage.

[Lumpy Grits]

Could have been from a previous stage. I've seen it happen before.
Sure sounds like an over-pressure issue, more than OOB.

LG

[PJ Hardtack]

That's a good theory, but .....

The RO that ran him as well as the spotters were unaware of a miss or a squib on the previous stage that could have resulted in a stuck bullet.

Had he suffered a squib, his rifle would have been immediately checked. He was shooting fully loaded .45 Colt BP rds. Hard to overlook a squib.

[Lumpy Grits]

If he is a fast shooter-Very easy to miss a squib.
I'll never have that issue, as they use a Sundial to time me.   
LG

[Coffinmaker]

A squib??  A squib with BP??  Pullese .........

[PJ Hardtack]

A squib??  A squib with BP??  Pullese .........

Exactly! He is a competent rifle shooter, but not a 'speed' shooter. His match pistols are a '60 Army and a Walker '47. Sound like a race gunner to you?

[greyhawk]

Exactly! He is a competent rifle shooter, but not a 'speed' shooter. His match pistols are a '60 Army and a Walker '47. Sound like a race gunner to you?

PJ
My son shoots an unmodified Yellow boy - a '60 army and a '47 walker - all with full case blackpowder loads - somebody gave me a picture of him crankin that yellow boy - three emptys in the air and the fourth just leaving the action - I wonder could he stop in time if that third round was a squib? Interesting question huh

[PJ Hardtack]

I'm sorry I even mentioned the incident. Now we're down to how fast he operated the rifle. Yes, he's pretty quick, but so fast that a full house BP squib (?) wouldn't be noticed? Yeah, right ......

All the speculation and theories, especially those coming from people who haven't even read the previous comments on the topic are becoming an irritant.

Please - forget I said anything about the matter.

[Coffinmaker]

PJ .... No good deed shall go unpunished .. Murphy