Blogs come, blogs go.
The Beagle Express was in my blogroll for a few years. Started by J.T. Hunter, it was eventually taken over by Trajectory.
The Beagle Express is no more, and Trajectory has found himself a new home.
This post is pretty interesting for firearm enthusiasts. We call the extremely rare instances when a gun catastrophically fails to be a "kaboom". The gun comes apart when it is fired, we knowingly exchange rueful glances and talk about the kaboom.
But what happens when the gun is ruined but it doesn't fly apart? What do we call that?
Comments (1)
Propogation of this longitudinal crack appears to be the result of a metallurgical defect. This is likely due to a nonmetallic inclusion or lamination which became elongated when the steel billet was rolled into bar stock. It would be interesting to know the serial number range of this revolver and when it was made, as it may reveal something about the QA processes in place when it was manufactured. I know a bit about this and have seen it before.
When I became QA manager with the company (1984) we worked through some material problems with 4140 steel produced by Republic and LTV when they hit the skids. Some barrels failed in a mechanism similar to the one pictured.
"Most of the time" such defects are centrally located in the core axis of the bar and are removed by the gun drill. Occasionally you do not get it all, and the barrel will then, at least theoretically, fail during proofing. That's the reason why you proof guns in the first place!
This type of defect is caused by improper "cropping" of the cast steel "ingots" into "billets" at the steel mill, which then become elongated as the billet is rolled into "mill-length" bars about 30 ft. long. These are cut to lengths as needed to forged or extruded to contour, or gun drilled, then rifled and profiled, so if one barrel fail, there will be others too which came from that same bar.
As the poured steel ingot cools, a conical cavity is produced at the pour point, caused by solidification shrinkage. For this reason the "one top" cut during cropping is routinely discarded at the mill and remelted. In gun barrel, ball or roller bearing and pressure vessel quality steels, the buyer will also specify "ingot position" and require that the "two top" cut be discarded and not rolled into bars.
This was not being done on some steel lots when I arrived, so I changed our steel purchasing specs and QA process to require it, as normally done on DoD contracts, and to have either our metallurgist or the government's Quality Assurance Representative (QAR) present at the mill to actually witness the cropping in order to certify the ingot positions specified.
Further manufacturing controls which greatly reduce the probability of such defects getting out into production is the implementation of 100% ultrasonic and Xray inspection after proofing. This is normally done on rifle receivers and bolts and revolver cylnders of magnum calibers, but was deemed unnecessary for revolver barrels, as peak pressure has dropped by the time the bullet leaves the cylinder.
Yes, it's a scary occurance when it happens, but I have never heard of an injury being caused by a "KaBLOOP!"
Posted by ke4sky | April 10, 2008 9:25 AM
Posted on April 10, 2008 09:25