SpudFiles

This is my latest Marble shooter I have made. It is my favorite shooter I have made yet. I don't have much to say about it. Here is a list of some important specs:

-Breech load system
-3/4 inch QEV for the valve
-I have shot it at up to about 350 PSI
-I have mounted a cheap Daisy laser sight, works good.
-All made of copper
-Chamber is filled with a fridge pump/compressor
-It is very comfortable and holds like a "real gun"

I have got a marble to penetrate a 2X4 piece of wood and show through the other side, but not blast all the way through and exit the back side, if that makes sense. I am hoping that I can make it through both sides of a 2X4 with a tighter fitting or heavier ammo. Any ways, This is my baby, and she may not be ultra clean, but I am still proud of her.

very interesting breach setup, I must say. I would suggest:
a) wrapping the marble in paper towel or tissue or something to get a better seal.
b) take your fridge compressor all the way up to 500psi or more, mine went easily to 600 and wasn't about to stop. Your QEV can take much more than that.

also, fun you can have:
-wrap a needle in tape, and shoot it at a coin at point blank
-(if you have a chrony) make really light ammo out of balsa or what ever, and see how fast you can shoot it. I got >1000fps (5/6 the SOS)

I feel uncomfortable taking either the valve or the blowgun up past 350 or so. Plus I dont have a guage that goes up past 300 yet. I like (LOVE!) the idea of more power but I would rather work in a range that I feel comfortable with.

I like the idea of shooting a coin with a nail. I really wish I could afford a chrony, It would be sweet to see how fast these marbles are going.

About the paper towell wadding idea, I can see that working, but it seems like a hassle. I am trying to find a steel ball bearing that is a nice tight fit, If anyone knows of a website that would sell that, let me know. please?

Looking good Jook! Bring on the damage pics!

cool looking cannon, but i would have put the breach further back to maximise barrel length

This is my baby, and she may not be ultra clean, but I am still proud of her.

Justifiably so, great job

jook13 wrote:I am hoping that I can make it through both sides of a 2X4 with a tighter fitting or heavier ammo.

Heavier ammunition will travel slower and therefore probably increase ft/lbs but reduce penetration depth. If you want to maximise penetration, you're going to need some form of APFSDS. If I could make a suggestion:

i agree with lentamentalisk. tissue will work great. finding steel ball bearings online, paying shipping, the losing the in one shot is a lot of trouble. the tissue gives u a decent seal without the excess weight of a steel ball. more weight means that u cannon works much harder unnecessarily. the cannon is great though. i love copper.

Put a bell and a mouthpiece on that thing and you've got yourself a trombone...

Nice job. Full 2 x 4 penetration is impressive indeed.

Noice. Looks a little unweildy but cool....

whyyyyyy didnt I use a store - qev in my gun... ugh. it looks so much cleaner.

overall, nice job, u better make some vids....

@jook13 it looks good and powerful...

@JSR

Heavier ammunition will travel slower and therefore probably increase ft/lbs but reduce penetration depth.

AFAIK heavier projectiles penetrate deeper...

POLAND_SPUD wrote:heavier projectiles penetrate deeper...

If fired at the same velocity, with all else being equal, then yes. However, fired from the same launcher, the heavier projectile will travel slower making the equation more complex.

There was some relevant discussion on the matter here.

One word: Funky. 8)

@ JSR

However, fired from the same launcher, the heavier projectile will travel slower making the equation more complex

first of all there is no proof in that thread that higher velocity = more penetration...

you can't compare penetration of .177 and .22 pellets which have the same KE and then draw conclusions... they have different diameters, which is likely to have an effect on their ability to penetrate.. it would make sense if you compared two projectiles that have the same diameter but different weight.. for example 15mm marbles and 15mm ball bearings... anyway I think it's better to discuss it in that thread since jook might not want me to hijack his thread

Gippeto: Thanks man! I plan on destroying things this weekend... with video and pics. Any suggestions?

ALIHISGREAT: Thanks for the compliment. I have a few reasons for my design of the breech. as it is, the whole barrel slides out a few inches until the notch appears to put the marble in. Then it slides back. I didn't want the barrel to come completely out because it puts added stress on my support and it just seems uncool to do that. Plus that notch acts like a little stop to keep the marbles from rolling out the barrel when pointed down. As it is, there is about 3-4 inches between the ammo and valve, which I don't think makes much of a difference.

jackssmirkingrevenge: again, thanks for the compliment, I love building these contraptions, though I feel guilty for using a pre-made valve. Its just so easy. I like the idea of the sabot nail with fins, a lot. any suggestions for attaching fins like that? I doubt JB weld or epoxy would hold something like that, and I have no welding experience.

i-will: I like the idea of steel balls for their more uniform size. as it is now, I have to test fit my marbles and throw a bunch away for being too big or small.

more weight means that u cannon works much harder unnecessarily

I don't really care about the cannon working harder, there aren't many parts to wear and tear. Plus heavier objects mean more energy and I would imagine more damage, which is cool even giving up some penetration.

starman: Thanks buddy. the trombone statement is funny cause it does kinda look like that. Guess my next project should be getting a trombone to shoot marbles.

VH_man:thanks for the compliment.

Noice. Looks a little unweildy but cool....

It is a bit long, but as long as it fits in the back of my truck, it isn't too big. The one thing I don't like about it is every time I bump the barrel on something, I have to re-zero the laser sight.

POLAND_SPUD:thanks!

markfh11q: thanks? 8)

As to this discussion of weigh vs penetration, I find it interesting. Guess I will find out when I get steel balls in from McMaster... Unless someone here knows of a cheaper place to get them...

As for Targets, Shoot a Bannana. Its epic.........