Cool, I figured it was fine but I want to be 100%. Thanks for your help.

I bought some 4" sch.40 PVC and it is pressure rated at 110psi. Im wondering if anyone knows if that is just the standard for clear PVC and if thats enough of a pressure rating for a propane fueled launcher?

Awesome gun but one problem...ABS is not pressure rated. It could weaken and explode. I'm not being critical but that is very dangerous. ya im pritty shure that would be bad. last time i used one of thoes tanks it chought on fire. dident explode "untill 6 hours in"but was shooting out 3 foot flames...

I would try screws instead of nails for adjusting the depth or penetration. Also if you use wood screws, you might not have to sharpen them.