Safety first, even as you build.

[Acer Saccharum]

Folks, I blew the muzzle on my rifle this weekend, from shot starting the load. More here:
http://americanlongrifles.org/forum/index.php?topic=6386.0


Why do I post this here? Number one, EVERYONE should read this post. It can happen to you.

What has this got to do with building?

Two, as a BUILDER, I would have done things a little differently, had I been aware of this issue when I built the gun. I cut my dovetail way too deep for this wall thickness. This has been mentioned many times over the years to NOT cut dovetails too deep, or at all, in the waist of a light swamped barrel. The danger is that the wall thickness will be too thin.

This shows the wall thickness over the dovetail, thinned even more, as a rifle groove happened here as well. The groove plus the already thin wall gave the pressure a path of least resistance. the split started under the sight base, and tore for and aft from there. Fortunately, everything went UP.


Does that look too thin? Sure does to me. So WATCH YOUR DOVETAILS, builders. This is not even in a high risk area, normally, but in the future, I will thin the sight base down before cutting the dovetail. And if I MUST use a short starter, I will make it so it pushes the ball beyond the dovetail.

As a builder you must be concerned with SAFETY, perhaps the safety of someone you'll never meet, but nonetheless, you must build with safety on top of your priority list.

Tom

[Ken G]

Acer,
How deep is the dovetail?  I'm read in your previous post it is a .54 cal.  Is it a "C" profile barrel. 
Thanks,
Ken

[Don Getz]

Unfortunately, it wasn't the depth of the dovetail that caused the problem, it just happened to fall right where he short
started the ball.    Had he not short started it, he could have shot that barrel the rest of his life.    Short starting a ball is
a wierd thing, sometimes it will bulge the barrel, sometimes blow it up like Tom's, most of the time it will merely blow it out
the barrel.  We did a lot of testing over the years.  Tried to create the situation where the barrel would blow up when short started.   Every time it would merely blow the ball out the barrel.    The only way we could get it to bulge or blow the
barrel was when we loaded the barrel properly, with a patched ball down tightly on the powder, then short stared another ball.....this scenario would always bulge or blow the barrel.  Over the years there have been many barrels with the muzzle ends bulged or blown away, and probably in alsmost all of the cases, the shooter was sure he had rammed that ball home.   But, if you think about it, why would a barrel suddenly bulge or erupt as the ball was going down the barrel, pressure decreasing rapidly, unless there was an obstacle in the barrel......there would be absolutely no reason for
that to happen.  I'm glad Tom posted this, it just shows what can happen, especially if we are interrupted during the loading process.  How many on this forum have ever dry-balled a gun......weren't we sure we had powder down that barrel?  It can happen to anybody..............Don

[Acer Saccharum]

Ken, I think it may be a 'C' wt bbl. 1 1/16 nom at the breech, and WAS around .825 at the split, kinda hard to tell now.

As Don says, this would never have been a problem were it not for the location of the short start. This is not even the thinnest part of the barrel. I mention the dovetails on the waist, because it gets MIGHTY thin at those points. You may want to solder lugs on, or go with very shallow dovetails.

At the shoot, other members mentioned how they short started, and nothing happened, but another shooter got a ring in their barrel. Others shot their ramrods downrange, double charged, superimposed loads, and the list goes on.

The fact is, there is such opportunity for accident, that we must pay special attention to the task at hand.

Tom

[Ken G]

I totally agree that the depth had nothing to do with the barrel bursting.  I was just curious how deep it was. 

Ken

[ironwolf]

  Excellent post.  Gotta' tell the story now.

   A friend of mine, who happens to be a range officer and very safety minded, had a similar experience.
  After cleaning a flinter he re-installs the lock and forgets that the set trigger is set.  He goes to the range and approaches the bench and notices that the top jaw screw is loose, cocks the lock to tighten 'er up and leaves it cocked while lining up the flint, with the frizzen down.  Sets the rifle down and drops powder down over a fully cocked lock with a set trigger. 
  First stroke of the rammer sets her off and shoots the rod out of his hand nearly tearing off a couple of fingers.  Bent the rod double and broke the wrist of the rifle.
  Distraction and complacency are bad, bad things at the firring line.

  KW

[Acer Saccharum]

Sorry, Ken. The dovetail was about .055 to .06 deep.

With an across the flats of approx .820. and .54 cal, and rifles about .01 deep, I get a min wall of .130. SUbtract .06 dovetail from that, and I get .07 wall over the rifle groove. Seems like plenty of wall, especially out where it is....UNLESS..... the ball is short started right on that spot.......

Tom

[roundball]

What an incredible chain of "long odds" events....ALSO forgetting the frizzen was closed at the time he was loading a cocked Flintlock...AND then had the bad luck for an errant spark to make it into the main charge.

Best step way away from that guy if lightning starts in the area...

[Sean]

Ouch... Was that the smoothrifle on your web page?  I'd hate to lose any gun you built, Tom.

Anyway, one of the reasons I always hate going to the range is that I'm always the only one there with a traditional muzzleloader and everyone want to come by talk when I'm loading.  Takes a lot of focus to make sure you are doing everything right.  On the dovetail issue, it was likely the difference between a ringed barrel and a split one.  I'd much rather ring it, but either way you are going back to the shop to replace it.

Sean

[billd]

A good thing about this is that the barrel maker used a steel that held together, no fragments flying around. Thank God for that, no one got hurt.

Bill

[Dphariss]

I am replacing a barrel on an  "entry level custom" kentucky that came to me for inspection that has 2 dovetails in the waist that are too deep and long.
Will solder the lugs on the new barrel.

Dan

[jwh1947]

Yep, no need for a dovetail to be deep.  Incidentally, regarding safety, whenever a person presents you with a muzzleloader, contemp or period, pull out the ramrod and drop it down.  Measure the length to the breech plug on the outside and make sure the rod goes in that full length.  Not once, but twice, in this little shop, I have been handed a loaded rifle, one likely loaded 100 years ago.  And, yes, we just had to try the powder in an ashtray outside.  It blew off without a hitch.  JWH

[frogwalking]

43 years ago, I had just shot a squirel with a 14 gauge flintlock.  It didn't fall like it was supposed to but clung valiantly to the linb.  I did a "quick" reload, aimed, pulled the trigger and had a misfire.  It must have scared him as he gave  up and fell dead on the ground.  In those days, I didn't know how to sharpen a flint, so I blew all the priming out of the pan, and installed a new flint.  Sitting cross legged on the ground, looking right at the pan to check out the sparks, I pulled the trigger.  A spark found the powder charge even with no powder in the pan, and the gun fired.  I was looking right into the flash hole.   

There I sat, blinded, a mile up on the ridge behind the  house.  I was wearing moccasins, so began to feel my way back down the logging  road  toward the paved road.  After a while I was able to blink my eyes open quickly and see a little.  It hurt so I didn't do it much.  To make a too long story not so long, I recovered, except for a little black spot that is only noticeable if I look at a blank wall.  Another case of an  unprimed flintlock firing.  No, I didn't forget the squirel. 

[B Shipman]

Glad you're OK. That must have been scary. I've made so many mistakes loading, I must have a guardian angle.

[rich pierce]

Guardian angle- is that when the parts fly off in a safe direction?

A dovetail induces stresses whether it's deep or not, the "notch" effect and so that's where it will go, if it's going to go.

[Michigan Flinter]

With that mishap Frogwalking had just reenforceses my use of eye protection when shooting  . I've seen several people have their eyes saved by wearing saftey glasses in my thirtyeight years around machineing . Was to a weekend shoot this summer and saw a person do the same thing as frogwalking did but didn't get hurt.A very lucky man me thinks.

[hyltoto]

It wasn't the depth of the dovetail that was the culprit, but the notch concentrated the stress. Look at most stuff you see cracked, and the cracks start at a scratch or corner. (think about cutting glass) So the dovetail notch was the initiator and the copression of the air in the bbl provided the energy. You need both for fracture.

I was reading how the early 1803 Harpers Ferry rifles would burst where the octagon to round transition occurred. When I turned my bbl, I made sure to file those tool marks out to avoid stress concentration. I use one of those chisels to put the undercut in my dovetails, sort of like rolled threads.

A good book written for smart practical guys like y'all is Structures, or why things don't fall down by J.E.Gordon. Covers everything from building Cathederals to lingere.

[jwh1947]

Frogwalking, glad you didn't get burned worse.  Not a muzzleloading accident but one based on lack of thought and unfamiliarity with the firearm, an acquaintance once took his brand new "Dirty Harry" S&W .44 Mag. out for its first shots and decided to steady the revolver by placing his left hand around the cylinder/barrel connection, right at the cone of the barrel. They debrided the wound at Hershey Med Center and put a nice bandage on it.  $375 ER fee.  Embarrassment and a decade of continual ribbing, priceless.  Any of us doing safety instruction could have prevented this through lesson #1.

 Also, never, ever depend on the safety mechanism of any firearm as fail-safe or positive; yes, some modern handguns with positive disconnects are very efficient, but I say make it a general rule, keep those muzzles downrange at all times, especially when you release the safety.  I've seen firearms discharge when the safety is released.  They needed mechanical services in the gunshop.  How do you know, for certain, that the next gun you pick up doesn't need some cleaning or repair in around that safety?  Then there's the ultimate unsafe safety on the Jap Type 94 with the external bar...touch it or shove it in the holster the wrong way and the gun goes off.  Faster and cheaper than a vasectomy. JWH

[Kentucky Jeff]

I've said this many times before but if you shoot a lot, sooner or later something like this will happen.  Even if you pay perfect attention, only shoot store bought ammo, etc.  Something WILL go wrong.  Its not a question of if...its a question of when.   If you have been a gun enthusiast your entire life and have never had something like this happen then count your blessings.   

When I was 14 years old I lowered my shotgun unloaded out of a tree with a rope just like you were supposed to.  As soon as I got myself on the ground I heard a deer making its way towards me and as quietly as possible with as little movement as possible I slid a slug into the chamber and closed the action and waited.  In no time a 6 pointer popped out 15 yards from me...I smiled raised the Shotgun and fired.  The deer looked at me kinda funny and happily bounced away...  I was stunned.  NO WAY I missed that deer at that distance!  I walked over to where he was standing and began looking for blood sign...nothing!  That's when I looked down and saw that the end of my shotgun barrel was peeled back like a banana for about 4 inches!   Oh NO!  I worked all summer to afford that gun!   Turns out when I lowered it down the muzzle stuck in the snow and pulled out a neat plug of snow and ice that I never noticed in the hurry to get that deer!

A while back Sako had a recall on some of its Stainless Steel Model 75s.  They had a nasty habit of blowing up!  Turns out they had a bad batch of steel that didn't work properly in the hammer forge and the barrels left the factory with microscopic fractures in the steel that let go with just the right amount of use...

If you read Major General Julian Hatcher's book, Hatcher's notebook he did detailed reports of hundreds of gun blowups etc when he was in the Army.  It is VERY interesting reading and you quickly realize that even if your are careful and do everything like you should bad things can still happen...

Wear eye protection!  ALWAYS!

[Dphariss]

The Sakos may have had microscopic flaws.  I can't believe they forged the stuff.

Krieger does not recommend re-profiling any of their SS barrels or shooting them at temps under 0F.

The stuff stainless barrels are made from is "free machining" i.e. brittle. There have been failures in SS handguns too...

Dan

[Dennis Glazener]

OK guys, this was a good topic but its gotten into the modern stuff and you all know that's for another forum not for here.
I am locking this thread.
Dennis