SpudFiles

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Simple to make and to use.

No leaks or movement at 550 psi.

I think you posted this before, haven't you?

jrrdw wrote:I think you posted this before, haven't you?

No, it was just friction fitted.

i used someting similar except a compression fitting that i tighted down on the barrel then lossened again so i can take it apart. then the barrel slides inside a fixed peice of tubing.

<a href="http://s696.photobucket.com/albums/vv32 ... 0_9841.jpg" target="_blank"><img src="http://i696.photobucket.com/albums/vv32 ... 0_9841.jpg" border="0" alt="Photobucket"></a>
shown here open. it seems like you have quite a bit of trouble sliding it and this different way could fix your problem

c11man wrote:i used someting similar except a compression fitting that i tighted down on the barrel then lossened again so i can take it apart. then the barrel slides inside a fixed peice of tubing.

<a href="http://s696.photobucket.com/albums/vv32 ... 0_9841.jpg" target="_blank"><img src="http://i696.photobucket.com/albums/vv32 ... 0_9841.jpg" border="0" alt="Photobucket"></a>
shown here open. it seems like you have quite a bit of trouble sliding it and this different way could fix your problem

I have found that it loads and locks quite easily.

The barrel has to me moved less than 3/4" to clear the T.

A 1 inch rotation left or right and I can load an arrow.

All components hang together and no tools are needed.

A single click and she is locked.


I strive for light weight, Home Depot available components, and a minimum number of threaded parts.

minimum number of threaded parts.

Why would you want that?!
Threaded parts are great! easily changed, no glue, and they allow for customization of the launcher, the only time i don't use them is in PVC because its much cheaper, and i can just hack things off if i want to customize

i think mine is faster, the compression fitting is left hand tight so a quick twist its off then the barrel slides forward in the support. none of the twisting and binding i saw in the vid.

and i agree threaded fittings are great

c11man wrote:i think mine is faster, the compression fitting is left hand tight so a quick twist its off then the barrel slides forward in the support. none of the twisting and binding i saw in the vid.

and i agree threaded fittings are great

Well, to each their own.

Threaded parts are heavier than solder.

Read all the posts concerning leaking threads and you will find folks struggling with epoxy, tape, etc.

Well made soldered connections never leak.

(I have reused soldered fittings)

Then there is the issue of dead space.

The barrel of the Trom-Boyn fits directly into the piston T.

Does the threaded fitting offer a minimum of dead space?

Can you slide the barrel forward far enough in your design to breech load say, a 12" projectile?

Is there any breech less expensive than a barrel inside a T?

Those were my thoughts when I built it.

I also like to do things different than what was done before.

I have never seen a breech system like mine; pull out barrel and push it to the side to load any length projectile.

Your cannon looks fine.

What results have you measured? psi, weight, fps

boyntonstu wrote:I have never seen a breech system like mine; pull out barrel and push it to the side to load any length projectile.

I really really like this feature, you could shoot a freaken broom stick out of this if it fit the diameter. Red glow stick at night would be killer! Some body would call 911 claiming aliens where attacking lol...

Well made soldered connections never leak

just like a well made threaded connection

Then there is the issue of dead space

again, this is disputable.. I just added a quick sketch to show you how easily you can build a breech loading T with threaded parts... there is almost no dead space there



threaded fittings are much more useful when used properly

soldered parts are a bit lighter but at the same time they are not as tough as malleable iron or brass fittings.. you can smash a copper T with a hammer.. try to to the same with iron T

semiauto MKIII weights just 2.8kg... that's with all the things on it (including scope, magazine, vertical grip etc) and a couple of fittings I added to it just in order to increase its mass (so there would be less recoil)

but I like your breech loading system... pretty ingenious

jrrdw wrote:

boyntonstu wrote:I have never seen a breech system like mine; pull out barrel and push it to the side to load any length projectile.

I really really like this feature, you could shoot a freaken broom stick out of this if it fit the diameter. Red glow stick at night would be killer! Some body would call 911 claiming aliens where attacking lol...

Exactly why I designed it this way.

A few more improvements are possible.

Restrict the pull out travel.

Restrict the rotation angle travel.

Add a arc section stop piece to the T to make it simple to rotate the barrel into it for easier insertion.

Thanks again.

all valid points
on mine if this barrel was my only one then the compression fitting would serve as the coax conector and eliminate deadspace.
i havent measured but i think my barrel can slide forward close too 12inches. if i modified it it could slide forward close to 24inches with only the looks changed( barrel support slid forward).

and i do not have a crony so all i have is ggdt and it tells be 750fps with a 5/8in (.625) steel ball bearing at 700psi.

so i say its prettty good