I'm trying to figure out to make a bolt action paintball rifle which uses propane instead of co2 and uses a bolt system similar to the sl-68 made by tippmann. In this system a hammer is cocked by sliding the bolt segments together and the spring tension between them fires the gun. When the trigger is pulled the hammer end of the bolt slides back and hits a stem which pushes a diaphram back into a gas chamber releasing co2. How safe or unsafe would it be to adapt this system to propane and put in leads in the bolt that cause an arc, creating a fireball to propel paintballs or other projectiles. Would i need to place a cut off valve inside of the air chamber so it didn't fire back into the tank and kaboom, or would the pressure of the gas escaping keep it from coming back in? if so what could i do to prevent it from doing that when it got low on pressure. I might try it, basically it would be a repeater spud gun, pump action or bolt. I have an old sl-68 that i might convert if i can. would it be possible to easily convert propane to 1/2" thread because that's what co2 is. the bolt could probably be easily converted for electrodes, also how could i get a 9 volt to fire across about a 1/8" gap. Any suggestions would be great.

Looks cool, but I think you should do some serious reinforcing\thickening of the combustionchamber where the propane\air-mix ignites...I'm just saying this because I've done the same myself, and the fuqqer blew up and teared a wallsection clean off our garage...Once again, thank god for rigging a remote testfiring-system...I think you need two separate tanks for the half-auto spudgun, the minimal mixratio for any gas\air ignition is around 15-20% air, and in a combustionchamber(Airthight) you must mix the gasses from two separate tanks repeatingly for making a repeating spudgun, if you pull it off, please send me some blueprints and some fuelmixes that worked well... ;)

instead of using two tanks i had planned on using the initial pressure of propane to begin to propel the projectile down the barrel and once the air mixture is right the bolt will cause an arc. I will have to adjust the timing on this, that will drop the pressure in the chamber, and still push the projectile down the barrel. this will keep something brittle like paintballs from breaking. it's like cold firing a rocket sort of.

phyrelord: Have I missed something? Where does the air come from? You have a propane tank, valve gear, and the chamber and ball. Would you just be combusting the air in the chamber? How big is the chamber supposed to be?

It's not very clear what you're going about doing, phyrelord. I think a good diagram would do wonders to explain (including what the tippman action is would be good too).

Why do you need a 9 volt battery to spark across 1/8"? You cannot use a normal peizoelectric sparker because of timing or something?

Please explain how the flame could possibly "fire back into the tank". If there is no oxygen then the propane cannot burn. There is no oxygen in the tank. Therefore it is impossible for the propane to burn inside the tank and explode the tank. This strange and stupid misconception has to be one of the most common urban legend type things around. It pisses me off every time I hear it.

Mostly my post is to take beef with post number two in this thread:

Beethoven, how (the fuck) can you say that he should reinforce the chamber if you have no idea what he is making it out of in the first place?

You are wrong about the gas/air mixture. 20% air and 80% propane is far too much propane. 4% (by volume I believe) propane is just about optimal. To use this amount I have found it needs to be mixed with a fan in order to light but it does give the best performance. For more information see this excellent webpage:
http://www.burntlatke.com/
More propane, along the lines of 5% will make it easier to light.

You do not have to mix gas from two seperate tanks if you are using air as the oxygen source, as it seems he is planning to do. Instead you would have to air out the chamber.

I don't believe your story about blowing a wall off of your garage from a propane explosion. Just how big are you saying your combustion chamber was? Do you understand the concept that the same amount of gas is produced whether the chamber explodes or whether the gun fires properly? In other words your gun would have pretty much have to be so big as to blow the wall off even if it fired normally, which is rediculous.

Hi guys,

how come are we all argueing again?

Right, making a paintball gun that powerful might have some mad results. For christs sake don't turn out to a game and use it against your peers! Hit someone with that, and you might live with just a few bruises (then again, in the woods...) Only use it on some fucker who really deserves it.

As for the mix, try reversing it! Even then, 20% propane is a bit rich. 80% won't even burn, let alone explode. (It will burn as air gets to it, obviously)

As for fragging the wall, read the post properly, Sparky! He clearly states that the gun exploded on test firing. He doesn't claim it levelled his house! Plasterboard is not a strong material, and for a large spudgun, I can believe it. (Think standard plastic sewer pipe, 16" across, well mixed with air - Beethoven_1983 just might be that dumb!)

I doubt that you would need to reinforce something like the Tipman, though I don't have my other half's on hand to check. It seems pretty sturdy. The problem you will have, however, is the backpressure, which paintball guns aren't designed to take. You will trash your seals in one shot, and that will be that.

Using a 9V battery to ignite the mix will only work if you use a coil and/or a capacitor, and so you might have problems with the timing.

The ball, however, will almost certainly be fine paint mist!

in order to mix the oxygen properly i had planned on the ball being about halfway down the barrel then exploding, further accelerating the ball, would this work or will i have to introduce fresh oxygen. I also don't have to worry too much about the seals there is only one of them excluding the o-ring that attempts to seal the barrel off. this link shows the basic operation of a pump gun http://entertainment.howstuffworks.com/paintball2.htm any ideas on mixing the propane w/the oxygen would be great. could i use a different gas that is more forgiving?

As jack's complete has already started your painball will be uterly distoyed and your seals will defently be distroyed for sure. Most painball gun operate at 1200psi or less most 800 usually. Also most paintball guns fire a paintball at just under 300fps as they tend to loose acuracy with anything over 300fps not only this but i have had a marker shoot hot at just under 350fps and my paint was breaking from the friction caused by the air so theres no way in hell your gona get one to go Mach 1.

Not only this but why propane powered just use Co2 or compressed air most high pressure systems start at 3500psi and go up too 5500 psi so theres more than enough pressure. Just work on fireing a heavy 68cal round like a lead round out of your paintball gun at 300fps as it would make a good high kenetic energy weapon. I imagine it would work great on small mamals like squirrls at 100' of closer

chem burn i had not intended on it going mach 1 it's just what i designated the project, like the car. go speed racer, sorry;). Also the reason for this is just for novelty's sake, plus would be really fun to have a paintball sniper rifle not intended for anything less than 100 yd shot i'm going to try to make special sabot to fire paintball but that's another thing. also thinking about using .50 cal paintballs instead of .68 caliber. also would be cool to show up at the field with a semi normal looking gun that belched flames. This is just a project. And thanks for the link to burntlatke.com that helped a lot. I figured out that i'll need at least a 24" barrel to get this to work. it will need to fire when the ball is about 11.04 inches down the barrel to get right propane/air mixture. or will just letting the vacuum created by the ball suck in air work to mix air with propane should i make some kind of venturi to swirl the air around?

As for the mix, try reversing it! Even then, 20% propane is a bit rich. 80% won't even burn, let alone explode. (It will burn as air gets to it, obviously)

As for fragging the wall, read the post properly, Sparky! He clearly states that the gun exploded on test firing. He doesn't claim it levelled his house! Plasterboard is not a strong material, and for a large spudgun, I can believe it. (Think standard plastic sewer pipe, 16" across, well mixed with air - Beethoven_1983 just might be that dumb!)


No, I think even 20% is far too rich. Propane has a fairly small range of flammability. Even for hydrogen I think the upper limit is about 19%. Take a look at that burnt latke site and you can see some tests they did with propane mixtures.

Hey, accusing someone of not properly reading a post carries some serious disrespect so make sure you mean it if you say it. I think I interpreted the post correctly:
Beethoven said:
"and the fuqqer blew up and teared a wallsection clean off our garage..."

and my response was:
"I don't believe your story about blowing a wall off of your garage from a propane explosion... In other words your gun would have pretty much have to be so big as to blow the wall off even if it fired normally, which is rediculous."

In other words I never assumed Beethoven was claiming the explosion "levelled his house."

Edit: Point taken about the arguing, I was just pissed off at Beethoven's post and the bad start that this thread seems to have gotten off to.

Ether would be better than propane, as it will burn over a very wide range of mix ratios. Thats one of the reasons its so good for starting manky old cars.

problem with ether would be introducing it into the gun, it would probably work better but it would be hard to introduce the gas into the chamber.

As far as ignition goes a ignition coil from a old car or car shop and 9 volt would last a little while. A better system would be to just buy a cheap stun gun. Lowes sells a electronic push button grill ignitor that would be perfect and only uses an AAA battery.

For this whole idea I'd just rig up a small potato gun sort of thing. Forget about things combusting in a paintball gun, they're just not made for anything like that.

I just cannot understand why you're all (some exceptions) are trying to make us look stupid by drawing your own infantile conclusions, Hear us out instead. what I ment was: If phyrelord made his combustionchamber for repeated shots, He had to equip his gun with two separate gas tanks,who mixes the gas\air in a ignitable ratio,and regarding the gun,do what I've been very clear about in at least one of my posts, the secret lies in the lamination. An inner pvc-tube,glued and inserted into a thin coppertubing, this is being glued and wrapped in a carbonefibered netting,glued, and inserted into barely bigger steel tube, this is glued, and thightly wired with thin steelwire. Insert this into whatever design you want, yes, a such device did rip the inner wallsection clean off my garage, if some of you think leveling the house is the same thing, well...bad for you...

Of course, it was after the incident with my friends when we made the demolition-gun, I started the laminating, scared shitless, not tkaing any chances, my first spud with laminated chamber and barrel looked like a doomsdayweapon. Later I learned to scale it down, and use several thin layers separated with nets and thightly winded wire, and lots of maritime epoxy enforced with glassfibre. I've recently made a pcp-gun with such barrel,and a scuba, working on the triggering system now...Any ideas? :rolleyes:

Beethoven_1993,

I was backing you up! Anyway, I too was pissed off with the arguements. People who are too antagonistic tend to get banned.

Sparky,

Hydrogen will explode at conc.s between about 7% and 97% with Oxygen (iirc). The range in air is very wide, too, in fact about the widest you can get.

I have seen paintball guns doing 400 fps at competitions. I went to a walk-on day, which was a bit mad, and they chronoed all the guns after lunch as there had been some complains. One guy had his set to dead on 400! That is 33% over the limit of 300!! Mine was set to 300, and it gave 301 on a few shots, average about 298. They asked me to tweak it down a bit, but I didn't bother, since the higher velocities were after ten shots+, and then dropped as things cooled. This would never be an issue at close ranges.

If you have one of the better guns, you can simply unlock the adjuster, and turn the power right up. This is to adjust for colder days, when you need more gas for the same velocity, and hot days when the oppo is true.

If you want blazing velocity without breaking your paint, try getting a venturi bolt. I have one, and you never get broken paint, as the bolt never actually hits the ball! What normally happens is that the ball gets a smack to start it moving, and the gas then pushes the ball out. The venturi has more holes in it, so the gas gets out faster. Also, your bolt is lighter, so the gun fires even faster!

I say forget this as a project, and just get a newer, better paintgun. Turn it all the way up, and you will be able to put down 15+ shots per second at 400+ fps, in .67 cal! Freeze the paintballs hard in your freezer for killing rats!

jacks complete i have a tippmann A-5 w/flatline and e-grip not having a good gun isn't really my problem. Mine is cranked open all the way for all those angel toting yuppies whose mommy and daddy bought theirs for them:) chronoes about 350-375 now with the new expansion chamber. I just want something unique. The guy at the local field knows me for this with my 98custom with an underbarrel scattergun. He wanted to buy it from me but ii gave it to my cousin for christmas when i got my a-5. I'm an individualist, i have to be different. what i'm planning on doing is similar to the effect of a venturi bolt. The 90 psi that propane creates will start to push the projectile down the barrel once the mixture is right the electric arc will ignite the gas further speeding up the ball so as not to rupture it but gently accelerate the ball down the barrel. I think i've figured it out i'm going to test it this weekend if it works i'll try to post info.

Jack, I know hydrogen has one of the highest flammability range, that's why I used it as an example. It seems I misremembered the actual limit though,
http://www.c-f-c.com/specgas_products/hydrogen.htm

http://www.hydrogensafety.info/articles/04-feb-04.asp (http://www.hydrogensafety.info/articles/04-feb-04.asp)

The sites agree to limits of 4% to 75%. 18% being the lower explosive limit. It may have a higher range in pure oxygen but I don't suppose there is much point in using pure oxygen.

I've found it hard to get a good mixture with ether (though not unusably hard). So I was surprised to find Tuatara was right about it's wide flammability range, about 1.9% to 36%
http://www.orcbs.msu.edu/newsletters/July1993/haz_mat_report.html
http://www.osha.gov/SLTC/healthguidelines/ethylether/recognition.html

Compared to propane at 2% to 10%
(http://www.technocarb.com/natgasproperties.htm)

I suppose the fact that ether comes out if the can as a liquid makes it easy to add too much.

I think i have a perfect solution to your problem of breaking paintballs...DONT USE A PAINBALL!
I recently aquired a 0.61 inch solid steel ball bearing, and when shot from my tippman 98 reaches 380 fps and easily shatters 2X4's. I went online and found a site which manufactures CUSTOM ball bearings and odered 2000 of them. I'd bet that with your propane mod, it's power would rival that of my H&K .45 P7M10!!!

I went online and found a site which manufactures CUSTOM ball bearings and odered 2000 of them.
Have you got a link for them? How much did 2000 cost?? Doesn't it knacker the gun? Hell, what is the recoil like?

I have a spare... :D

i've thought about playing hopper roulette with these before http://www.pbreview.com/products/reviews/1499 they're called t-balls one to a hopper of 200 would make the game more interesting. i'm not trying to kill things. i want to make a super paintball gun that shoots .68 caliber PAINTBALLS. i still have to get a stun gun shipped in and i'll have it together. hope it works, i'll post pics when i get it all together.

Have you got a link for them? How much did 2000 cost?? Doesn't it knacker the gun? Hell, what is the recoil like?

I have a spare... :D

I will answer your questions as they come.

Firstly, It is my custom never to give out web links except in rare cases. I beleive that those who are do mentally deficient to figure out how a search engine works, have no business playing with such dangerous toys.

Secondly, my first batch of 2000 set me back 150 bucks...pretty steep, however some of that was shipping (the full crate weighed nearly 300 pounds). However, I sold 500 to my best friend, and 500 to his brother for a 80 bucks a bag, so i have already made back 160 dollars!

As to your second question, yes is definitely does. However i sumply use my stock Tippman 98 barrel whenever im shooting bearings. The wear can be reduced by lightly oiling the balls so that they slide easier.

Another great way to get FREE ball bearings is to SWIPE the mouseballs out out the old school mice. Simply remove the rubber coating and VOILA!
The only problem is that they are too large for the regular tippman barrel. I solved this by borrowing my friends FREAK BARREL (with the changeable sleeves for different ball sizes). The largest ball size works great for the ancient beige Macintosh mouseballs. But make sure your balls are well oiled(sorry but the pun), cause THE FREAK is freakin expensive!

Recoil is pretty bad on the highest pressure, but nothing like my .50 Desert Eagle AE. If you can shoot even a low-powered handgun, then this should be no problem.

EDIT: I just had a thought...I wonder what a well oiled ball of plasticzed PETN would do when shot out of a PB gun! Someone insane, PLEASE try this and post the results if you live! Ill post this request on the TOTSE and MISCHEIF forums too...those dumbasses will try anything.

-=PEACE OUT, AND HAPPY HUNTING=-

EDIT: I just had a thought...I wonder what a well oiled ball of plasticzed PETN would do when shot out of a PB gun! Someone insane, PLEASE try this and post the results if you live! Ill post this request on the TOTSE and MISCHEIF forums too...those dumbasses will try anything.
Like stuffing a kilo of HE into a car and fragging it from ~90meters away? :P

That sounds like a good idea, but I suspect it would be a remote test for the first shot!

I see what you mean about the link to someone's site, but I suspect you are being a little over-cautious, since you are probably in the states, and I am not. I will have to see how well the local shop can re-grind BBs - I got a whole load of old ones for nought, because they aren't round yet - this place re-grinds them to round, and sells them back to the sellers! Great for catapults, but wouldn't feed at all!

As for the recoil, I can imagine it being quite fierce for a single shot from an empty gun, but if you are trying to use the hopper feed, and spit them out fast, what happens? Or is it single shot only? Both my guns are semi's.

As for the recoil, I can imagine it being quite fierce for a single shot from an empty gun, but if you are trying to use the hopper feed, and spit them out fast, what happens? Or is it single shot only?

The problem with using a hopper full of the bearings it that a full one weighs about 20 pounds, with only 3 loaded into the elbow though it shoots fine, and is manageable. I am working on a 10 round low-profile feeder from sheet metal that will be light, but still provide plenty of firepower.

As for the PETN rounds....well...Im still a chicken bastard. Even if a remote firing SUCCEDED, if one ever went off in the barrel due to some freak occurence it would be all over. It would totally frag the barrel, and turn the gun into a lethal pipebomb. If me or anyone else came up with a SAFE, reliable method of firing i would try it.

I have been working on modifying .45 cal HOLLOWPOINTS into EXPLOSIVE ROUNDS. I am trying to make a larger cavity in the bullet and pack it with PETN desensitized with RDX. This should allow the bullet to be fired without detonating, and still be sensitive enough to initiate on impact. The trick however is getting the right mixture. I am slowly adding more PETN to my RDX mixtures until I find one that will detonate upon impact...The waste of RDX though is enough to make one cry! :(

So how many guns do you have Not_Osama? No offense, but to me it sounds like you dont have all these guns you claim you do.

How much do those bearings weigh?

So how many guns do you have Not_Osama? No offense, but to me it sounds like you dont have all these guns you claim you do.


I own 4 handguns: A H&K 9mm P7 Compact, a H&K .45 P7M10, an original model .380 Walther PPK(similar to the one James Bond used in his older movies), and my new pride and joy, A .50 Desert Eagle AE Mark XIX with 24K gold finish. If you would like pics for verification, i will attach them as soon as i get back to civilization. For now here is a catalog pic of my new baby
http://www.magnumresearch.com/Expand.asp?ProductCode=DE50GO
click on "gallery of guns" if you want a larger pic.

On a side note, I bought this with my tuition refund!

I own 4 handguns: A H&K 9mm P7 Compact, a H&K .45 P7M10,

You sound like you don't know what you are talking about.

A HK P7M10 is chambered for 10mm Auto ammunition
not .45 ACP. There is no such model as a "HK P7 compact"
There is a HK P7M8 and the older HK P7 PSP variant.

Also in an earlier post, you said a crate of 2000,
0.61" diameter steel balls weighed 300 lbs. The weight of those is more like 66 pounds - did you really order those?