Originally Posted by billdeserthills
Having received & printed out your photos, I can only think of one reason why a gun barrel would split like this & that is a Squib Load. Since 22 rimfire is not a caliber you can feasibly load yourself, do you know what ammo you were shooting when this happened? I would guess the ammo manufacturer is actually responsible for the damage that has occurred.
He said the first three shots hit the target.
The failure happened on the fourth shot. It couldnt have been a squib.
Are the roughrider barrels forged or machined? This looks like the effect of impurity elements in the metal during the forging process. See how straight the crack is? And note how it runs through the fromt sight machined pocket? (Read: weak(ened) area)
Technically: To eliminate the anisotropic plasticity of columnar grains and the danger of cracking during forging, the process must be conducted within narrow temperature and deformation limits. These conditions, however, are not always applicable to the central equiaxed zone. Such an anisotropy leads to microcracks during upsetting of ingots and bars with traces of columnar structure.
My bet is a finite failure analysis would find a high concentration of sulfur, phosphorus, copper or tin in the make-up of the failed area (crack). Too bad a failure mode analysis would cost more than the barrel replacement, but from this engineers old eyes, you got a lemon.
That or it just done blowed up.