Pneumatic Mortar

[quigly]

Not to mention a nerf ball isn't a giant shot gun.

[Matt]

Nerf projectiles as opposed to hard projectiles that might hurt somebody - yes. But a shower shell is perfectly acceptable. Lots of people use them out of 203s. People just use the nerf footballs because they have range. Sometimes they are the preferred prop for anti-vehicle because they are big and easy to see. Shower shells are better for anti-personnel.

And I don't care if you wanna use some flour in there to simulate a plume of smoke. I don't care if a little bit of flour hits my gear. We get covered with mud, sand, paint and soaking wet at most games. I expect to get dirty. Most of the BBs are going to fly farther anyway, the flour will just poof out as a cloud when you shoot. Coolness factor.

[Arbiter]

OHHH!!! I have one!!! hahahaha I made it up as I was going along never herd of em before but Its really similar to this design mine shoots 20oz soda bottles that have a foam tip pretty nifty..

[Falcon7]

So do you guys have PSI gauges, safety valves, and whatnot on your mortars? I want to add them but there is no great way I have found other than drilling a hole and applying gorilla glue.

[anubis]

a real simple solution that my team had good luck with was get a 2 inch bore pcv tube. add cap with a bolt dead center for a firing pin. then add bi pod, tri pod ect..

as far as the round is concerned get a 1 1/2 or 1 3/4 pcv tube. dremmel pcv so as to create a snug fit to any 40mm airsoft grenade. our best result hs been with the madbull pb4 co2 shells. chop pcv so there's a 4 inch gap between the top of the grenade and the end of the tube, then add a 1 each nerf pocket rocket foot ball.

on propane we were arcing the ball a good 120 feet up and between 150 to 250 feet out

bbs tended to get a good arc but only about 50 feet

[Icepick]

I actually have something like this that I built to fire nerf darts... Only problem is that the nerf darts are way too light and cont. curve right, even at 40-60psi. I'll post pics here in a second.

[Icepick]

[DJ]

For now I drilled a hole smaller than the valve treadings and cut it a little bigger and bigger until the valve could fit in with a bit of force. Then I put glue all over and shoved it it. I'm trying gorilla glue for now, if it doesn't work I will try something else. If you can find whatever pipe the valve is meant to be treaded into you could cut a hole for it and glue it in there.

Anyway, I didn't build this for AP events necessarily. Mostly just for ridiculous games with my friends and messing around. It could be a great element to add to an OP though.

If you want to build your own you need to use ABS or PVC rated at sch 40 or higher. Basically you have a 3" by 1' air chamber, then a ball valve or something you can open and close to let the air out, then a 2" by 2' barrel.
On the air chamber you need to put a schrader valve or whatever kind you want to fill it with, a pressure gauge, and a 125psi safety valve.
With sch 40 pipe you can fill the mortar up to 100 psi max. For airsoft purposes you most likely will not have to fill it up to very high pressures. Use at your own risk.

Very nice. One suggestion for people to heed. ABS ( according to company that makes spud guns) is kind of dangerous as it will splinter and cause fragmentation when/if it fails. I would recommend schedule 40 (or higher) PVC for safety purposes.
Very cool mortar, I was researching building one but it kind of got shelved. What is the range on your BB rounds? and at what PSI? I like the bb rounds as there will be no " I was outside the kill radius" calls to make as with the nerf. Also no lost nerf footballs, a pain in the butt when they are out in the weeds.
also check these out
http://www.milsimlabs.com/foam%20ordance%20mortar.html
If you can score an old scuba tank ( for an air source), they make a pigtail for them to fill inner tubes etc, that would work nicely for your mortar......

[dr.feelgood]

Very nice. One suggestion for people to heed. ABS ( according to company that makes spud guns) is kind of dangerous as it will splinter and cause fragmentation when/if it fails. I would recommend schedule 40 (or higher) PVC for safety purposes.

Are you sure you don't have those switched? Because I'm almost positive that it is PVC that will shatter.

[DJ]

Very nice. One suggestion for people to heed. ABS ( according to company that makes spud guns) is kind of dangerous as it will splinter and cause fragmentation when/if it fails. I would recommend schedule 40 (or higher) PVC for safety purposes.

Are you sure you don't have those switched? Because I'm almost positive that it is PVC that will shatter.

I'll go and recheck the source, However I'm almost positive that the ABS which is drain pipe, is not pressure rated like SCH 40 ( 400 psi) or 80 ( 800 psi) PVC pipe. You will also note that all of the spud gun sources have disclaimers stating that you make spud guns at your own risk due to the fact that this pipe is not intended for this purpose. What you are making in a mortar is a spud gun with a different projectile. The various spud gun sites are a wealth of information.......checking now.

update:
I cannot find the exact site right now. This one
http://www.spudgunextreme.com/faqs.htm
has a lot of useful information re pipe. What I could find sort of confirms what you said about PVC splintering. Regular spud gun (SG) users state that it is wise to wrap PVC SG with fiber reinforced tape in the event of pipe failure to prevent shards fragging you. The site recommend NOT using ABS pipe. There are a butt ton of spud gun sites out there with a lot of information, short version is use extreme caution with this unintended use of PVC pipe.
I have used ABS pipe extensively for DWW in housing, drain fields etc. It is not rated for static high pressure. Use at your own peril

Still later: I checked some SG forums ( yes they exist!) there is a lot of debate re ABS vs PVC. What was sort of the consensus was ABS works pretty well for combustion ( hair spray SG) but is not recommended for Pneumatic ( air powered) guns. There is a company making / selling rifled PVC for the do it your self SG manufacturers. That would be cool to try with a nerf to see if it increases accuracy / distance.
http://www.spudtech.com/detail.asp?id=32
This company sells a lot of cool SG components

lastly, read this and decide:
http://www.spudtech.com/content.asp?id=14

[CalvinB]

Most ABS is not pressure rated, meaning that they don't test it, however most people agree that cell core is good for at least 50 PSI and solid, sch 40 ABS ($$$) is a few hundred PSI. The failure mode of PVC is to shatter where as ABS which tends to rip and split. Through my own experimenting in a shoulder fired nerf gun, I know first hand that ABS will take at least 45 PSI, and that at that pressure and a 2:1 chamber to barrel volume ratio, it shoots about 250 feet, and does a lot of wear on the football tail. A usually run it at about 30-35 PSI but at 25 PSI, you're still outside of rifle range.

[DJ]

Most ABS is not pressure rated, meaning that they don't test it, however most people agree that cell core is good for at least 50 PSI and solid, sch 40 ABS ($$$) is a few hundred PSI. The failure mode of PVC is to shatter where as ABS which tends to rip and split. Through my own experimenting in a shoulder fired nerf gun, I know first hand that ABS will take at least 45 PSI, and that at that pressure and a 2:1 chamber to barrel volume ratio, it shoots about 250 feet, and does a lot of wear on the football tail. A usually run it at about 30-35 PSI but at 25 PSI, you're still outside of rifle range.

Please read the links re cell core. They specifically advise against using that type of pipe.

[CalvinB]

I'm aware of it but people I have talked have said that the fear of ABS is founded completely in the fact that it is unrated, and not an inherent weakness. The people that I talked to regularly use them and many are years old. They built them just for poops and giggles just to see what happens when they fail, at how fragile they are, but what they found out is that it is strong than they thought. One gentleman is a kids summer camp counselor and every year pressure tests it up to 100PSI.

As a finished product, I can stand all 170 pounds of me on the side, in the middle of the chamber on the ball of one foot with at ambient pressure and operational pressure. The only safety test I have yet to do is to put it up to pressure and shoot it with a sniper rifle at minimum engagement distance.

[Switchback]

My brother and his friend used something akin to a tire pressure gauge that was attached to the tank somehow. That part broke off because it was poorly attached, but I remember it being helpful when they filled it.

[DJ]

My brother and his friend used something akin to a tire pressure gauge that was attached to the tank somehow. That part broke off because it was poorly attached, but I remember it being helpful when they filled it.

Tire or sprayer gauge , sprayer is pipe thread.