SpudFiles

ammosmoke wrote: I was under the impression that using carb/engine cleaners is a bad practice. I don't think that using such a strong chemical is a good idea.

As long as you don't huff it or take a bath in it and don't do generally stupid things with it, it's not any different that any other flammable fluid we use in our daily lives.

However, using a fuel that's packaged properly and meant to be burned for energy...ie. propane..is really what ought to be encouraged. Spray and prays really shouldn't be much more than a 10 or 20 shot curiousity before moving on...IMO of course.

So are you saying that it's better to have your chamber smaller than your barrel?

Its'd better to have your chamber have more volume then your barrel, IMO.

n-strike wrote:So are you saying that it's better to have your chamber smaller than your barrel?

Read through the discussion that preceeded this question again. Ideal c:b ratio for a combustion falls into the .5 - 1.5:1 range. This is only an efficiency window and says nothing about absolute performance.

The .5 would mean the chamber is smaller by volume than the barrel...the 1.5 would mean the chamber is larger by volume than the barrel.

Increasing your chamber size, while keeping the same barrel will always improve performance some but your efficiency goes down and much of the extra energy is wasted as heat and sound after the projectile has left the barrel.

The dynamics of this is different with a burst disk.

about the only way to find out the best performance is trial and error, use anything that says flammable and see how it goes. i would think rocks would be hard to get a tight fit which is what you want, the tighter the better. i think the barrel length is fine, just whatever you prefer.
good job on the guns u made.

My chamber is 1 foot of 4" PVC, and my barrel is 2 1/2 feet of 4" PVC. Would mine be alright?

EDIT: Wait...I forgot this was Combustion...mine is Pneumatic...Anyone know the ratio for that?