What I want in an anti-tank cannon.

[Smakman]

I have been searching the internet to see if I can find where someone has built a cannon like what I have in mind. So far, I have found a few that were close, but none that were just what I would want. Here are the criteria that I am looking for.

COMPACTNESS. I want it small enough and light enough that it isn't overly burdensome to carry along with other equipment for extended periods of time. I think a design with the barrel inside the pressure chamber and a piston valve might work best for this. Or a short barrel with a relatively short pressure chamber configured in-line.

SPEED. I want it to have a triggered valve that will dump air into the barrel quickly. The faster the valve opens, the lower the pressure required to launch the load. A hand operated ball valve is simply not fast enough unless the shooter sacrifices accuracy to slap the valve open as quickly as possible. Sprinkler valves work fairly well, but are still somewhat bulky when using a 2" bore cannon. If only someone made a 1/4" sprinker valve!

AIR SOURCE. I don't want to have to use or carry a seperate air source to power it if there is another way. My idea on this is to mount a good quality bicycle pump to it. They now make bicycle pumps that will pump up to 135 psi, far more than required to shoot a 2" foam rocket. If a CO2 source is used, I would want it mounted in-line with the pressure chamber, and regulated so as to automatically repressurize the chamber to the proper psi after the valve closes.

Cosmetics. Not as important, but it does need to look kind of cool and realistic. I prefer the look of a LAW.

Any more suggestions?

[p8ntball72]

check out..
http://www.xinventions.com/main/spud/home.htm
lots of info on air cannons.

the one i built runs at 60 psi on a 12 gram.
will launch a nurf rocket 60-80 yards if i run 100 psi.

[TheTramp]

As soon as I can get them hosted, I'll post some of mine and give the specs to give you some ideas.

[Smakman]

Thanks. Wow, some neat stuff on x-inventions.

[TheTramp]

Here's mine:

http://www.cyclelandspeedway.com/temp/AOHOST/cannon1.jpg

[doc_Zox]

heres the basic 12 gram LAWS guts:
http://www.darkviking.com/modules/coppermine/albums/userpics/10060/normal_LAWSchamber.jpg

heres the barrel:
http://www.darkviking.com/modules/coppermine/albums/userpics/10060/normal_chamber%26LAWS.jpg

you need ~2 feet of barrel to make a 75 yard punt

[tjmpaintball06]

i will build you a cannon to your specs. I use a sprinkler valve to fire. Any size expansion chamber is possible but i prefer a 6 inch galvanized pipe with a 12 gram quick change adaptor. It automatically fills the expansion chamber and propels 30 balls great. If you want a U type i can do that too. Just e-mail me at tjmpaintball06@yahoo.com for details. Prices vary for different options.

Thanks:)

[Rhinopkc]

http://www.bp-usa.com/weaponry.htm
I have one of their's, it is by far the best I have seen. I have made several of my own that work really well, but for size to performance, BP's is the best.

[Smakman]

Yep, that what I am talking about, but what a price tag!

[doc_Zox]

i've been waiting for someone to review the Blackpoint online

how does it work?

can you adjust the velocity?
hows the breech open?

what sort of valve does it run?

any batteries?

dZ

[kemikos]

So I picked this one up on Ebay as a collector's item... Unfortunately, the barrel was destroyed in shipping. Fortunately, I was able to rebuild it into a pretty darn nice Nerf tosser... :)

This is my USI Destroyer.
http://www.ameritech.net/users/kemikos/Destroyer1a.jpg
This picture shows the whole launcher. It's fairly compact - I've seen smaller 12-gram cannons, but most are significantly larger than this. The BP LAW is at least twice as long... (Incidentally, it came with a holster, albeit a pretty big one. That's right, this baby's holsterable!) :D

It's basically a "ball valve" style PVC launcher with an ingenious trigger system that releases the spring-loaded valve lever. Here's a shot with the valve closed...
http://www.ameritech.net/users/kemikos/Destroyer2a.jpg

I'm surprised how well it shoots, considering the barrel is pretty short (the tail of the Nerf round sits at about the middle of the white repaired area - you can push the Nerf in all the way without a ramrod). Currently it shoots well over the legal limit; I estimate I should be able to get 3 full-power shots from a 12-gram once I add a regulator for better velocity control...

Anyway, that's my new toy... :D

[doc_Zox]

thats pretty impressive performance for a 12 gram

it looks like the vortex only seals the last 3 inches of the barrel

will it sail a nerf 75 yards?

[Rhinopkc]

Originally posted by doc_Zox
i've been waiting for someone to review the Blackpoint online

how does it work?
Overall function of the unit is very good, it's just like shooting a gun, pull the trigger and it fires. It is very dependable, I have had no malfunctions.

can you adjust the velocity?
Yes, there is a knob on the front of the unit to control velocity with.

hows the breech open?
There is a button under the barrel, at the front of the launcher. The unit can be opened by grasping the top of the barrel, pressing this button with your index finger, and sliding the barrel forward about 1/2 inch. The barrel then tips forward and the rocket is inserted into the breech. There is nothing to cock, so as soon as you close the breech, the unit is ready to fire again. After familiarizing yourself with the unit, you can easily fire a rocket effectively every 10 seconds.

what sort of valve does it run?
I am not sure, but I think it's either a piston or a diaphragm valve

any batteries?
no, the valve is pneumatically actuated

dZ

The only gripe I have is that the launcher was not prepped right before paint, after 1 scenario game, the paint is sliding off of the launcher.

[doc_Zox]

it appears to be a high pressure design

a piston valve is usually a low pressure high volume affair

i would bet if you wrote up a review War Pig would publish it

[Rhinopkc]

If constructed properly, a piston valve can be used at any pressure. The launcher has a built-in reg, so it could be operating at a lower pressure, I don't know where to install a gauge. A piston valve is probably overkill for this application, I think the launcher utilizes a diaphragm valve.

[doc_Zox]

so how many shots do you get off of a tank?

our Ballista drinks deep from the CO2 tank

[Rhinopkc]

I don't have an exact count because i was using a nitro tank and I had all day air, so I was topping off whenever I came in for a break. I can get 3 shots off of a 12 gram. I need to get a smaller compressed air tank, I have an 88/3000 aluminum, after a full day of play my butt was dragging from the extra weight!

[kemikos]

Originally posted by doc_Zox
will it sail a nerf 75 yards?

Don't know yet. I live in an urban area, so I haven't had a chance to test for range.

But does it matter? I'm only going to use it for scenario games, where launchers are limited to the same velocity (230 FPS, for any producer that uses GSRP 3.02). If your launcher is getting 75 yards @ 230 FPS, then I'd say yes, mine will too (same projectile + same muzzle velocity = same range).

The Destroyer is a high-pressure design (up to full CO2 pressure - around 850 psi), though, so it accelerates the Nerf faster; it shouldn't need as much barrel length. It might waste more air than a low-pressure design, although since the valve opens faster than most, it might not.

The pressure chamber is a 3.5 oz. CO2 tank. The air line attaches to the on/off valve, and the butt end of the tank is welded to a fitting that attaches to the ball valve. The bolt in front of the grip frame is the velocity adjuster. It blocks off part of the air passage to slow down the expanding gas. Effective, but wasteful. A regulator should make velocity control finer and more efficient. Fortunately, it just so happens that I have a spare Stabilizer laying around here somewhere... :)

Oh, and while I haven't used one of the Blackpoint LAWs, I got to see the prototype last year. Rhino has it right; it's a solid, foolproof design. All I know about the valve is that it's air-piloted; I do remember the BP rep saying that the production models were going to be limited to under 200 FPS. I don't know if that's actually the case or not.

Kenn

[Rhinopkc]

Where did you get that m-14 mag?

[kemikos]

Originally posted by Rhinopkc
Where did you get that m-14 mag?

http://www.extremesportsandhobbies.com

The M-14 has been discontinued, but you can still see the info page at http://www.extremesportsandhobbies.com/m14.html.

Kenn

[Rhinopkc]

That's a shame, they keep all of the crappy looking ones in production and get rid of the best looking one.

[Smakman]

Thanks for all of the info on the Blackpoint launcher. Sounds like it is exactly what I want. Now, to come up with a reasonable excuse to spend the money on it........

[Rhinopkc]

you won't be sorry

[kemikos]

Originally posted by Rhinopkc
That's a shame, they keep all of the crappy looking ones in production and get rid of the best looking one.

Oh, if you come up with the money and ask nice, Vance'll probably build you one. Apparently they didn't sell too well; I was told there are about 5 of them (Mine's the only one with a real wood stock). :cool:

You want to see a really cool discontinued model, check this out...
http://www.extremesportsandhobbies.com/m60.html

:D

Kenn

[rkjunior303]

guys,

i was lookin to make a grenade launcher type law attached to a wood stock.. I didn't want to use a ball valve though -- I was thinking a sprinkler valve.. the electronic trigger is rather easy so that wouldnt be a problem but I had one question...

Would I have to use a anti-syphon valve? Since I was mounting this on a stock, i would really love it to be inline between the barrel and the 12g quick change.. Would an inline sprinkler valve work or does it HAVE to be an anti-syphon valve? (unless they make inline anti-syphon valves)..

[TheTramp]

I'd use an anti-siphon if the tank will be on it's side.

More importantly, you'll need a CO2 friendly reg that will keep your output under 100psi. I'm planing on using 12grams then switching to a Max-Flow reg

[doc_Zox]

a palmer stabilizer makes a great inline pressure regulator

but by the time you pay for that
and mod a sprinkler valve and buy X bucks of plastic pipe & fittings

yer geting close to a down payment on the BPE unit

and the head ref is going to want to inspect yer handiwerk...

[Rhinopkc]

Originally posted by rkjunior303
guys,

i was lookin to make a grenade launcher type law attached to a wood stock.. I didn't want to use a ball valve though -- I was thinking a sprinkler valve.. the electronic trigger is rather easy so that wouldnt be a problem but I had one question...

Would I have to use a anti-syphon valve? Since I was mounting this on a stock, i would really love it to be inline between the barrel and the 12g quick change.. Would an inline sprinkler valve work or does it HAVE to be an anti-syphon valve? (unless they make inline anti-syphon valves)..

You do not want to use an anti-siphon sprinkler valve, you need to use an inline valve and modify it to trigger pneumatically.Like this (http://www.geocities.com/tbrown111083/sprinklervalvesoupup.htm)

[TheTramp]

Originally posted by Rhinopkc


You do not want to use an anti-siphon sprinkler valve, you need to use an inline valve and modify it to trigger pneumatically.Like this (http://www.geocities.com/tbrown111083/sprinklervalvesoupup.htm)

That's a great mod. I've got mine set-up like that and it dumps the chamber much more quickly than the solinod did.

[rkjunior303]

Originally posted by Rhinopkc


You do not want to use an anti-siphon sprinkler valve, you need to use an inline valve and modify it to trigger pneumatically.Like this (http://www.geocities.com/tbrown111083/sprinklervalvesoupup.htm)


Thanks! that is perfect! That will be great.. Now, onto the air supply.. If I have a 12g quick changer going into the inline, what will I need going between the two to make sure it's around the 100psi mark? Will the 12 grams of CO2 alone make sure of this or do I need some sort of reg between the quick change and the valve?

[TheTramp]

If you're using a quick change all you'll need is a small dump chamber between the changer and the valve.

To determine the sizes of everything you need the barrel volume, dump chamber volume, dump chamber pressure, and velocity you are trying to get.

For example mine has these stats:

Barrel: 15"x2"
chamber: 7"x3"
chamber pressure: ~75psi (one 12gr)
Vel.: ~250fps

One 12 gram CO2 cartrage fires a nerf rocket at around 250fps. If fired at an angle it will sail at least 75 yards.

[rkjunior303]

ok so a 2'' barrel will fit those nerf rockets cool. >That's probably exactly what I need then since That is what I was looking to use... now, what do I make the dump chamber out of? :) (sorry for so many questions!)

Also, on any threads, will Loctine 545 (pneumatic thread locker) be sufficent? I use it on all of my fittings.

[rkjunior303]

Oh, using that setup how long is your completed LAW? Would that be moutable onto a wood stock for a grenade launcher type look?

[doc_Zox]

this one is a good guide:
http://spudtech.com/content.asp?id=22

http://spudtech.com/images/products/tbl250-2.jpg

[Rhinopkc]

A 42 cubic inch chamber will give you 100 psi from a 12 gram. Zox, did you buy one of those from Joel?

[Rhinopkc]

Also, I have had better results with 2" sch 80 for the barrel, the nerf rockets fit tighter. The rockets fit too loose in sch 40 and fall out sometimes.

[rkjunior303]

rock on.. thanks guys! i'll make sure I post pics when I finsh. now the dump chamber before the sprinkler valve can be made of PVC as well, correct?

[doc_Zox]

Joel's launcher is a great value

and has all the right parts

like the guage and the 125 psi safety valve

you need that on any PVC chamber

i have not bought one from Spud Tech yet...

Right now i'm working on a low tech, low cost Piston valve design

[TheTramp]

I bought Joel's 100psi gauges for my launchers. The nice thing is that you only have to drill the hole. THe threads of the gauge will tap for themselves.

I am suprized to hear that there are problems with the Sc.40 pipe letting rockets fall out. I've never had that problem.

[Rhinopkc]

They get real loose with temperature changes, sometimes they fit real good, sometimes they don't. With the sch 80, I get a nice, tight fit, with better accuracy. I spent a lot of time and money experimenting with different designs, my final design is breech loading, with constant air. If you build one, you MUST INSTALL A POP-OFF VALVE! If you don't, 1 malfunction can kill you!

[TheTramp]

Originally posted by Rhinopkc
If you build one, you MUST INSTALL A POP-OFF VALVE! If you don't, 1 malfunction can kill you!

Even when only using 12 grams?

One 12 gram only gives me ~75psi and I only charge it when I'm ready to shoot so it's not going to heat up. I can see if I was using reg'ed constant air but....

[doc_Zox]

wanna see my new ghetto charger concept?

http://www.performancebike.com/shop/Profile.cfm?SKU=16499
http://www.performancebike.com/product_images/400/40_1550.jpg

a pop off will prolly be required by a thorough judge on a plastic chamber

its a $9.99 investment in anti-Darwin logic
http://www.spudtech.com/detail.asp?id=17

[rkjunior303]

that's pretty cool. just have a fill nipple on the charge chamber and fill it with a 12g connected to that?

[TheTramp]

I use one of those! Well, not that exact one but still.

I just got a 12gr quick changer that I'm going to start using.

I guess it won't kill me to order a pop-off from Joel and put it on.

I'll put up a picture on mine tonight.

[doc_Zox]

yep! a schrader tire valve and i'm GTG

with a quick change one co2 shot is all you can load, you could double fill with the schader valve

some folkes claim if you use a rubber tire stem for the fill port, it can act as a pop off too...

my other LAWS have crossman quick fill CO2 but the bike dealie is on sale this week for 13 bucks...

heres some other good hardware:
http://www.cooper-t.com/expansionchambers.html

http://www.cooper-t.com/miscellaneous.html

[rkjunior303]

that's a good idea.. that would allow a fill to 100psi with the proper gauge on the fill port... I may pick one of these up!

[Rhinopkc]

If you're only using a quick change 12 gram, you probably don't need one, but for 5 bucks at Lowe's, why not be a lot safer?

Zox, those inflators are great for charging mines as well!

[TheTramp]

Here's mine. I still need to paint it. I also haven't filled in the solenoid hole with epoxy so I have to keep it in there for now.

http://www.jayloo.com/lib/get_file.php?id=1800

[doc_Zox]

one more step:
http://www.dickblick.com/zz014/11/products.asp?param=0&ig_id=6372

Krylon Fusion Plastic Paint

The first no-sand, no prep, superbond spray paint for plastic! It creates a professional finish that won't chip, peel, or fade.

Use it indoors or out on a wide variety of materials. Dries for handling in 1*hour.

[TheTramp]

I've heard of that paint. It looks great. Have you used it?

Does it come in olive drab or matte gray? I don't see a huge selection of colors on the site.

[doc_Zox]

i have yet to try the Fusion

i wonder if you use if as a base coat, if you can get wild with regular paint on top

only the Black & white are listed as Gloss...

Krylon® Fusion

Color & Product Offering
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Blue Hyacinth - 2333
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Espresso - 2340
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Gloss Black - 2321
Gloss White - 2320
Honeydew - 2335
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Navy - 2326
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Nickel Shimmer - 2338
Patriotic Blue - 2329
Pewter Gray - 2439
Pumpkin (Safety) Orange - 2337
Red Pepper - 2328
River Rock - 2323
River Rock - 2423
Spring Grass - 2327
Sun Dried Tomato - 2332
Sunbeam - 2330
Twilight - 2440
White - 2420

[Rhinopkc]

I've used it, it's better than regular spray paint, but it's no miracle like they claim.