OK, here's the scoop on the barrel. On the left we have Exhibit A, the test barrel. Note the breechplug is pinned in with a single 1/4" pin. On the right we have Exhibit B, the suspected actual Yooper Assault Rifle barrel. Note there are TWO 1/4" pins securing the breechplug in that case. While it may not be readily apparent to the untrained eye, these innocent looking barrels were both insidiously cut from a single length of J525 HydraBrite hydraulic pressure tubing, 3/4" OD by 9/16" ID. Indeed, they were cut in a calculated and premeditated fashion, such that the breech of one originated from as nearly as possible in the same area of tube as the breech of the other. After completing the necessary drilling, reaming , and assembly, the test barrel was escorted to a remote location for further interrogation. In preparation for this event, two measurement zones were marked onto its surface directly over the powder chamber area. These zones were 90 degrees apart and spaced about 1.25" longitudinally along the barrel. It was determined the barrel measured .751" at each of these locations.
Next, the test barrel was loaded with 70 grains of FFFg black powder and 7/8 ounce of bird shot. This was fired by cannon fuse. No expansion was noted in either measurement zone.
Then, the barrel was loaded with 140 grains FFFg black powder and 1 3/4 ounce of bird shot. This was fired as before. No expansion noted.
Then 210 grains of FFFg blackpowder, and 1 3/4 ounce shot. No expansion.
Then 210 grains FFFg and three .530" lead balls. No expansion.
Following this testing, the test barrel was disassembled and examined very closely. There were no defects noted in the breechplug or breechplug pin. The barrel surface was inspected by observing light reflected off its surface at a shallow angle. A very slight ripple was noted on each side of the fuse hole, outside of the measurement zones. The barrel diameter measured .752" in the area of these ripples.
After much beer drinking and tossing of coins, it was determined that the barrel known as "Exhibit B" might possibly be safe with a single .530" round ball and 30 grains of FFFg blackpowder. Or maybe 60 grains FFg and 3/4 ounce bird shot, if executed in mid-air during a "base jump" and an ambulance was on standby. Considering that J525 tubing has a previous record of being fabricated from plain low-carbon steel, it was felt that the possibility of metal fatigue ruled out routinely using charges which would almost certainly be withstood in a single test shot.
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Originally Posted by Expatriate
CNC (CAD/CAM) Gunsmithing
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