Disaster averted? Also, you need to know the yield strength to make a calculation. Without knowing the grade of steel, assume it's the weakest stainless in existence, plus the weld seam.

If I had the money, I'd make 3 of every cannon I have and test two to failure under different conditions. That way I'd really know the safety factor in a practical way and discover the weak spots and failure mode. Unfortunately, you could buy a nice car for what all that would cost, so it is what it...

How much pressure are you going for? What will you be shooting out of it and what velocity are you going for? If the answer is "maximum power to shoot a bullet-like thing", then there's really only one formula I can think of that makes sense: 4140 (or similar strength alloy), burst disc, big bottles...

That's a great response from the ATF. I don't understand and never will why some countries treat spud guns as if they were literal nuclear weapons and the people who build them as if they were literally a dangerous and violent war lord in need of immediate imprisonment. It baffles me why any governm...

Get crackin! Feed us pics and vids.

Don't beat yourself up over it. Bad things happen. That's why we try to be careful, but bad things still happen sometimes. We all have our stories and experiences. You shouldn't feel shame for what happened. It was an accident. They happen. Maybe try lead pellets instead? Steel tends to be pretty bo...

I'm pretty sure Larda holds the record for highest mix, at least the "public" record. 190X was totally insane.

I almost blew my head off one time. I never considered the risk of it and no one ever mentioned it, but one day I walked out to the firing line to shoot a pistol and forgot to put my ear muffs on. So, I put them on with a LOADED PISTOL in my hand. I basically pointed a loaded gun at my own head whil...

People have had success using a spark plug connected to a stun gun at 10x. I use a cheap stun gun and it's been reliable. I used one of those super cheap step up voltage thingies and it broke. It just stopped working. I think I even tried a second one if I remember right, and it broke too. Not sure ...

I have been using PVC potato cannon for about 2 years and I decided I wanted to make it shoot further. I use a grill igniter/spark plug wired up to 2 screws inside the combustion chamber to ignite the hairspray. One way I knew would make it shoot further was to wire a certain way with more screws t...

Beautiful work. This thing is cool. The spacing issue between faces reminds me of the headspace of a rifle; it has to be just right. I like it.

You could make a combustion cannon and toast those bagels on their way out! Just kidding, that's probably a terrible idea. Honestly, I think the best option is to build something different. I'm thinking go watch the slingshot channel on youtube and get some rubber-powered ideas to launch the bagels....

I missed this before. This gun is awesome. Legit full auto rather than a constant airflow with a tube stuck in the middle of a container full of BBs.

See link with external pressure ratings for PVC. They call it "critical collapse" pressure ratings. You can compare the critical collapse rating with the internal pressure rating. Critical collapse ratings: https://www.usplastic.com/knowledgebase/article.aspx?contentkey=777 Compare those figures to ...

What do you mean by buying an air tank and punching holes through it? Making a PVC cannon this large makes me especially uncomfortable.