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Posted: Wed Sep 29, 2010 8:36 pm
by MrCrowley
I just bought two barrels today. One 7ft long copper, 1/2 pipe, and one 5ft galvanized steel 1/2. They both have different inner diameters, for the two ammo types I will use.
Wait a sec, you're using 1/2" diameter barrels on a hybrid with a 2" union? I'd suggest building a different cannon for barrels that size and use this hybrid as a big-bore launcher.
Posted: Wed Sep 29, 2010 9:12 pm
by whoa044
By two ammo types, I meant two small bore ammo types. I'm not worried about any of the larger barrels failing upon firing. I plan on using the compound rounds by UltimateSpudGun as well. My goal for those would be at least 900 fps.
inonickname wrote:You should use the yield strength, not the failure one. You also need to add in a safety factor. Finally, the seam on that pipe and the galv (galvanising is done hot, and tends to soften the metal) will drop the strength by a lot.
It's not galvanized, and it's forged steel. The company does not provide any info on the type of steel used, but I was assuming it was at least 40,000psi tensile strength.