SpudFiles

I've built a couple of pneumatic marble rifles/cannons (sorry, new to the site, excuse my lack of knowledge of terms!) and it would be good if there was some way to keep the marble in the barrel without it rolling out when you tilt the barrel down, and be able to shoot down, and not have to "dis-engage" something before shooting.
(Sorry if this was complicated!)
Any ideas?

use some wadding?

^^^already answered.

also if you had have used the search button you would find a near identical topic on this subject.

a bit of tissue works well

Or you can find the perfect barrel,which is in australia 15mm PVC for electrical uses the marbles doesnt roll in the barrel but still moves freely enough to shoot out even wiht lung power.The perfect barrel,so look around for a barrel like this as it should be able to be found.

Why not wadding or a small stop of some sort.

Cork sabot? would work as well as cottton wool balls!

Plastic bags ect anything that is light and ductile will work fine.

What you can do is saw into the barrel a tiny bit (about 1-2mm) and then put an elastic band over the barrel, and to have a piece of the elastic go into that cut of the barrel.

The marble would need to be either muzzle loaded and rammed past the elastic band, or breech loaded behind the elastic band.

This is what I will use for my up comming BBgun

@ RNA:

down this part of aus we have no 15mm pipe

@ Mr Russ. Ask a electrition they have heaps of the stuff aks for the length you want and he hould help you out and it's pritty cheap!!

Bubba

yeah not real keen on using wadding etc.

rna_duelers, Mr Russ and Bubba05, are you all from Aus? (i am too)
rna, thanks for the advice about the barrel; I had a look in the shed and found that I actually had an ideal piece of 15mm pvc (thankfully you speak in metric measurements too!) I've just used copper pipe as barrels previously because I didn't think pvc would be any good, but yeah I think it's a winner! thanks mate!

Aussie Aussie Aussie OIE OIE OIE!!
Hell Yeah dude im from the land down under!!
PVC is fine for barrels mate ive never seen one blow out!!

Bubba

glue some foam at the back of the barrel so the marble is wedged.

_________________________________
_________________________________ =>barrel exit
^
foam strip

yeah cool, I reckon I'll have to give that a shot!
and thanks for going to all that trouble to 'type' out a diagram, nice work!

thanks. I used some stick on foam made for door frames. I always have trouble describing stuff with out a diagram.

p.s any one from Western Australia?