SpudFiles

It's going to work like this. You cock the cannon. When you pull the trigger the bolt slams forward hitting the BB.

The whole thing will be made out of steel so that it can withstand the slam of the bolt. I want to maybe use a 100lb. spring. Then I build the cocker so I can cock it with my foot or something.

What should I put at the end of the bolt so that it won't chip the BBs? And what should I use for the bolt stopper so that the gun doesn't break apart at the slam. And what can hold a 100lb. spring back?

It's going to work something like this.

I think the idea don't smells right.No way to get any amount of power.

Big problem,you are wasting energy.When the bolt strikes the bb it will cause it to fly a few feet at the most, rather replace the bolt with a piston, like a nerf gun.
Scroll down on this web site: http://www.compasseco.com/technical.html

And take a looky here: http://nerfhaven.com/homemade/boltsniper_far/

So a plunger or piston is better than a ramrod?

much, instead of just striking the object, it uses the built force to propel the projectile with air pressure

How much FPS you guys think I will reach with a 100lb. spring?

With out a piston the bb will fly no more then 5m.Sick of stupid ideas.

Most bb guns don't even use 10lb springs,you are really going overkill with one of those unless you are making something more like an air rifle.

good idea to use a hop-up too, it wont shoot very far unless you build up a decent ammount of pressure, by the way, how many psi does an Air rifle build up when it fires?

I dont think you are going to be able to set up i trigger that will hold back a 100lb spring.

This is essentially a BB gun without the piston. All you need to do is cut off that protuding piece that is meant to strike the BB and put an O-ring around the larger part. Then it will act like a piston. Large chamber, into a smaller barrel. Found a way for it to load whenever you pull back the cocking handle.

Nah, I'm going to use the plunger thing. I have a spring-powered nerf gun that uses a plunger so I'll just base it on that. How much PSI you think it will build up in the plunger?

If you have nerfgun, that you want to mod to BB-gun, then just replace barrel with smaller one...simple.

replace the barrell with a smaller one, and upgrade the spring to a 15lb spring, and a new trigger and cocking lever, then, you will have one kickass bb gun

Well I have a 100lb. spring already...So...And I don't think airsoft guns can handle this spring. I'm going to make this from scratch.