Y'all think 0.065" wall thickness is sufficient for a 2" OD tube?  Or would stepping up to a  0.125" OD tube be better?  Material is going to be 6061 T6.  

This is for a DeLisle build, so not susceptible to high heat/high ROF.

I used .065- 6061 for my 7.62x39 build 7 years ago and it's still going strong I have several thousand rounds through it. Its 1.5 OD and has been used on a 10.5 inch upper. Your pressures will be a lot lower as well.  


edited to correct typo

My integral 45WM is 1-3/8x.058.
You'll be fine ??

Awesome thanks.

Edit: guess is should have mentioned that there wouldn't be spacer material separating baffles like in a traditional can. The DeLisle uses two rods with spacers on the rods to separate the baffles. So the ID of the can is going to receive the full pressure blast

Sorry for the late reply, if you're doing a faithful reproduction your diverter over the barrel ports should be catching the full blast and redirecting it absorbing some energy. Then there is the brass sheet wrapped felt/asbestos liner over the main section that wraps the barrel area which would absorb some of the impact/pressure wave before the tube too. I used .065 steel on mine.

In a 5" barrel a max load 45ACP will generate 3248 PSI at the muzzle

6 gr bullseye 230gr LRN

Use the calculator found here
https://www.engineersedge.com/calculators/pipe_bust_calc.htm
To determine minimum thickness for your tube

That's a good calculator and a good starting point, but going by their numbers will result in a way overbuilt can.

That 3248 PSI drops off immediately and drastically due to volume. Napkin math - adding Boyle's Law to your numbers, that 3248 PSI is in a .71 cu in. barrel, assuming 5" - moving into a 1.87 ID tube, even if it tried to contain it all in the first 1" blast chamber, you'd only have 839 PSI.
Actual pressures to the tube wall will be less because the bore will allow pressure to bleed of immediately, from baffle to baffle, and even less again if your baffles are cup shaped since they'll be taking some stress as well.  Going back to your calculator: 2" OD with .065 walls, a conservative 20 KSI allowable stress rating, 1.5 safety factor: 867 PSI working & 1300 burst.

OP, you're GTG.

EDIT:  Add another 20-25% for a cartridge/barrel combo that's going to keep burning powder - like a 10.5" AR in .223 -  it's sloppy but it comes out pretty close and the actual math for that is a massive pain. .45 won't have enough unburnt powder after 5" to make much of a difference.