P.M.O.G Airsoft 40MM Projectile

[Hopewell]

As I have said previously in this thread, I think that this is a fantastic idea, and as Mazuran has said, I am convinced that these are safe IF wearing goggles.  From the power levels that you have stated (and backed up), albeit uncomfortable, I seriously doubt that they would take teeth out either.  On the other hand, these would have a set of safety glasses off in a jiffy;  For this reason, I can forsee that it would be an up-hill struggle getting these adopted and approved even with the generic "nothing is our fault" site disclaimer.

 

I don't wish to sound negative, but with a relatively low faith in my fellow man (example above, as per the Mall), I am just not convinced sites will accept them (and keep them fun)

[ninja master of coffee]

Mazarin, that's a better analogy! Yeah, some guy dropped one off a balcony and it landed on some guy's head which ment a trip to A&E. I don't know if they're still banned but it did illustrate the issue of riskier than average equipment in the hands of idiots. I actually really like the idea of the PMOG rounds, I'd be happy to go to a game with them on but honestly having them all the time and always having full sealing goggles would be a pain ( I use shooting glasses but don't use 40mm anything). Used correctly and with the correct equipment these look fairly safe, it's just that I think a lot of games would be inappropriate for those measures, partly, sadly because of the behaviour of fools.

[Avenger96]

It actually says at the end of the video that he was briefly unconscious due to being winded so hard from getting hit in the neck with the cannon round... what upgraded AEGs are you using?! I can see the utility and added immersion of using the PMOG rounds but you'd have to restrict use to games where people only have fill sealing eye protection. In the UK that is not a lot of games, most people use shooting glasses, simply saying "You didn't use the protection against this thing I just introduced, GOT WHAT YOU DESERVED!!"

Shooting glasses won't even protect you from a $10 springer. That's why the biggest field in my area has them banned.(the field is Red Fox paintball, I live in an airsoft deadzone, but I'm not to incredibly far from games in Charlotte NC and Atlanta GA)

[scorch]

Shooting glasses won't even protect you from a $10 springer. That's why the biggest field in my area has them banned.(the field is Red Fox paintball, I live in an airsoft deadzone, but I'm not to incredibly far from games in Charlotte NC and Atlanta GA)

Considering the rating shooting glasses have I smell trollbait.

[blobface]

I suppose they won't protect you from a $10 springer... it would damage your eyes pretty badly.. if you weren't wearing them.. 

[Avenger96]

Considering the rating shooting glasses have I smell trollbait.

They'll take anything on a direct hit, the danger is that rounds can pour in the from sides and behind.

[scorch]

Obviously I must have a massive moon-face or something cause there's no gap round mine.

[JCheeseright]

They'll take anything on a direct hit, the danger is that rounds can pour in the from sides and behind.

 

A large proportion of airsofters in the UK use shooting glasses for eye protection, myself included (I use ESS Crossbow and ESS Ice glasses), in my experience BBs coming in from the sides is not a problem and since they're accepted as sufficient protection at the vast majority of British airsoft sites I don't think many others see it as a problem either. 

[PMO Gordo]

I can think of at least 3 times I had BBs came through the gap between my goggle and the nose ridge - all during indoor CQB game play. It is likely that chances of BBs going through the gaps would be greater with shooting glasses.

[JCheeseright]

I'm not arguing that at all, of course full seal goggles are safer... paintball masks safer still.  I'm just saying that shooting glasses are safe enough for airsoft providing they fit well enough that there is no direct line from the big bad outside world to an eyeball the risk is negligible.  

 

I've never heard of anyone wearing a decent pair of shooting glasses getting an eye injury playing airsoft, not saying it's never happened, but in the 11 years I've been buying and using airsoft guns I have never heard of it. 

[Brigg]

Ive been playing airsoft for many years myself, all over the East Coast of the US. And never have I seen a field which allowed anything other then full seal goggles or a straight-up paintball mask. If I showed up at any of the fields that Ive commonly played at with shooting glasses, I would be sent home.

 

Considering that, I dont imagine this grenade would have much of an issue being used at outdoor fields in the US, provided that its shown that a direct head hit with it wont cause injury.

[CatgutViolin]

Guys, let's not forget that there are some pretty significant differences in how we play airsoft in the US versus in the UK. I've never been to a field in the US that allows shooting glasses, but I gather that they're very common across the pond. The outdoor field I usually play at, in fact, not only requires full seal goggles, but also requires some sort of covering over the lower face. You guys play with lower muzzle velocities than we do so it's not as critical to have face protection. It's not inherently better or worse, but keep in mind that Gordo is American so this is obviously tailored more towards our style of play.

 

For what it's worth, a paintball at typical velocity limits carries around ten joules of kinetic energy. The energy alone doesn't matter, it's the energy density (energy across a cross-sectional area) and the physical properties of the projectile that make it hurt or harmless.

[blobface]

Yeah because at this rate we might as well debate whether it's aluminum or aluminium... evidently a lot of people around the world play with shooting glasses, but also true that your sites in the US only allow for full face protection (probably due to the everyone suing everyone culture, they have to cover their bums for insurance purposes).. so this debate isn't really needed. 

 

That being said though, being hit by a large projectile like that or even just a cardboard pyro grenade thrown, if it hits your in the face and you are wearing seal type goggles, you might be okay, but if you were wearing shooting glasses, it could knock them off and expose your face for a short period to other risks... but you're probably more likely to trip and break your legs in airsoft than for that to happen.. 

[CameronZombie]

Except that there's no law in the US that states you must wear goggles while playing airsoft.  I know many, many people who wear their Oakleys, ESS's, etc (including myself) whilst playing.  In fact, I would give a rough estimate that only around 25% of people in my community wear goggles (and we're not a small group).  Also, in my community, we follow a slightly modified version of OLCMSS, so we have multiple rules to ensure everyone can be as safe as possible. It would appear that one of the few differences between the US and UK in terms of airsoft is that we have significantly less government intervention with our rules and regs.  We don't have a set FPS/Joule limit and hardly any other safety laws in the US.  So when you hear people say that the US is lawfully a goggle-only country, they're full of it.  Rules and regs vary from field to field.  The goggle rules are usually set by either indoor fields or the very large events to cover their *albatross* in case a kid gets shot in the face and goes to their parents.

 

That being said, I love this idea.  Perhaps a more pliable foam cover on the head of the round would work out some safety issues. 

[PMO Gordo]

The tip of the PMOG is a very pliable foam, made of Alumilite's Super foam 320. It shatters easily.

[Mike 8-{>]

Looks like a fascinating project and well done on all the decent research, both by experiment and of papers published in relevant fields. National differences in local practice and legallity of varieties of air weapons is always going to increase the complexity of achieving your goal of a useable ranged 40mm projectile.

 

I suspect that there are a bunch of areas of grey that may preclude such a device being available in the uk (or even just England as Northern Ireland and Scotland have differing rules either inplace or possibly pending for air weapons.) Please note I may be a bit out of date on some of this so am open to correction. In a generalised UK Replica Imitation Firearms or Imitation Firearms (airsoft weapons) of all kinds including, I suspect, 40mm grenade launchers are limited to a muzzle energy of 1joule (I know that this can be up to 1.2J or with local agreement more for single shot DMR/snipers but for the sake of argument it is 1J). Then we have air rifles and pistols which are differently classsified and fire metal projectiles with muzzle energies of 12ft/lbs / 16J for rifles and 6 ft/lbs / 8J for pistols. Strangely I believe paintball markers fall in to the air rifle catagory so are allowed the 16/8J limits (paintball markers are smooth bore so not strictly rifles). This strange differing between airsoft and paintball muzzle energies is a result of the VCRA and history / timing I believe. If it looks real but is a "toy gun" it is 1J. If it doesnt look real and is a paint ball firing air rifle it is up to 16J. By now I hope that you can see a 40J muzzle energy device, regardless of your well researched argument against the use of muzzle energy as a sensible indicator of lethality, would likely fall foul of UK law and not be allowed. So unless you can get your muzzle energy under 16J and fire it from something that doesn't look real or 1J and fire it from something that does look real I fear we will, at the moment, be unlikely to see one this side of the pond regardless of whether or not we wear shooting glasses, safety specs, mesh goggles, paint ball goggles, full face high impact chemical face shields or welders masks

[PMO Gordo]

 

Troops,

 

You might be wondering why I've been quiet about this project for the past two months. This is because I realized the limitations of the P.M.O.G 1.0: 1) Effective only when used with launcher with rifled barrel, 2) Unable to carry the projectile and the shell as one unit, limiting the amount of ammo that a player can carry. I find P.M.O.G 1.0 not very competitive on the market due to these limitations, and put the project on hold.

 

Now, I'm pleased to present to you the P.M.O.G 2.0, thanks to the accessibility of 3D printing technology. When I designed the P.M.O.G 2.0, there are several specifications I tried to follow:

 

1) Integration with the popular Moscart-style grenade shells.

 

Unlike the ICS/TAG grenade shells which cost US$ 80 a piece, the Moscart-style ones now cost as cheap as US$ 25. To make 40mm grenade launching truly as part of the Airsoft gameplay, it would be advisable to make use of the cheapest options. The difficult part of designing a projectile that works similar to ICS/TAG one is to allow players to carry the shell and projectile as one unit. Fortunately, many Moscart-style grenade shells produce approximately 1-2 mm of gap between the upper part of the shell and the grenade launcher's barrel wall. So, it is possible to utilize this space to attach the projectile to the grenade shell.

 

2) Compatibility with the common smooth-bore M203 grenade launcher

 

Smooth-bore M203 grenade launcher is the most common and cheapest model on the market. Although rifled barrels are available on several models, and they do provide better performance for launching projectiles, it is still better to make the projectiles usable on all 40mm grenade launcher models. An unique challenge from M203 grenade launchers is that due to the fore/aft only motion of the barrel for loading/unloading, the dimensions of the projectiles, specifically the length, must allow the projectiles to load easily from the breech.

 

3) Foster slug concept

 

I happened to learn about the foster slug that the hunters use to take down larger animals. The foster slug were designed to be fired from smooth barrel shotguns with decent accuracy. The trick is the deep hollow in the rear of the foster slug, which makes the center of mass concentrated at the front and stabilizes the slug in flight. The deep hollow in the rear, in the case of an Airsoft 40mm projectile, can also allows it to sit on top of a grenade shell securely and enhances air seal.

 

The P.M.O.G 2.0 consists of three sections, from top to bottom: 1) Tip: solid (for practice) or chalk-filled (for marking or special effect), 2) Midsection: the fins (if they are taboos for you law-abiding Brits, you can call them "wind channels" ) are mainly for minimizing friction and engaging the rifling (if there's any), 3) Bottom: allows the projectile to sit on top of a grenade shell.

 

I am currently making molds from my 3D printing prototype. The prototype costs me US$ 34 from Shapeway, so there's no way I'm going to use them for testing. After I produce several copies, I'll take them out for field tests. If everything goes well, I'll stick to this model and start mass producing it. I'll also make my Shapeway model available for order once I confirm its effectiveness.

 

I'm planning on making two types of projectile: practice and chalk-filled round. The practice round will be made of denser foam and have solid tip, which will make it more durable. The chalk-filled round will be made of lighter foam and have chalk-filled tip, which will make it safer for skirmishing. In addition, an accessory I'm planning to make for my P.M.O.G 2.0 is the "egg protector". What it will do is to sit in the 40mm grenade pouch and provide protection from impact for the projectiles.

 

Fig 1. P.M.O.G 2.0 integrated with Matrix Eagle Force Multi-Purpose CNC 40mm Airsoft Grenade Shell (Short type)

 

Fig 2. P.M.O.G 2.0 system in a 40mm grenade pouch.

 

More photos: https://plus.google.com/photos/111341442407880008659/albums/5928315087067854049

[Stuey]

Looking really good dude! Very promising.

 

If the fins cause the projectile to spin, that's a no-no for us Brits I'm afraid, I'm sure we can slightly alter the design though.

 

How's this for an idea - design the PMOG for the multi purpose/paintball shells that just have the big hole in the middle (like the one you've got there) and have the PMOG itself insert into the shell (so like a sort of mushroom shape). I'm not sure if it would make the whole device any smaller (actually looking at yours it wouldn't, yours is a smart design) but it might make the two halves stay together better. and perhaps look less like a dildo? That was the idea I came up with when I was trying to design a better 40 mm grenade anyway.

[PMO Gordo]

 

 

 

Looking really good dude! Very promising.

 

If the fins cause the projectile to spin, that's a no-no for us Brits I'm afraid, I'm sure we can slightly alter the design though.

 

How's this for an idea - design the PMOG for the multi purpose/paintball shells that just have the big hole in the middle (like the one you've got there) and have the PMOG itself insert into the shell (so like a sort of mushroom shape). I'm not sure if it would make the whole device any smaller (actually looking at yours it wouldn't, yours is a smart design) but it might make the two halves stay together better. and perhaps look less like a dildo? That was the idea I came up with when I was trying to design a better 40 mm grenade anyway.

 

 

 

 

Thanks for the suggestion. I actually tried your approach when I was modifying my Nerf rockets last year. The results were hilarious. The "stick" on the rockets often got left behind, and the main body of the rockets only flew a couple feet. At the end, I found out they worked best without the "stick" and fins on my EGLM launcher.

 

The best projectile shape for air weapons is probably the diabolo from airgun pellets. Here's a passage from Robert Beeman (a world-famous airgun guru)'s "Airgun Projectiles":

"...The most accurate airgun projectile is the modern, precision lead pellet with a waist that is constricted - giving the pellet an hour glass shape. Such waisted pellets are referred to as diabolo pellets in reference to the ancient game of Diabolo which used a wooden spool, with an hour-glass shape, which was juggled on a string between two hand-held sticks. The purpose of the constricted waist is to reduce friction and to provide a thin skirt which can expand to form an airseal and easily engage the rifling, even in bores of considerable manufacturing variation. Again we have a major contrast with firearms. The effect of most bore friction on firearm projectiles is swamped by the driving power of the powder's explosion and a relatively large bearing area is generally needed to provide, and maintain, good rifling engagement in firearms. However, modern airguns, with their limited power, derive considerable advantage using the diabolo design with its very limited areas of friction and expanding skirt. The aerodynamics of diabolo pellets are quite different than those of firearm bullets with long straight or curved lateralprofiles. Also, it is clear the ballistics of super-sonic projectiles (most firearms) and sub-sonic projectiles (most airguns) are also quite different..."

 

The keys are low friction and tight air seal, in addition to the forward center of mass. I could design my projectile as an enlarged copy of a modern airsoft pellet, but it wouldn't sit squarely on top of the grenade shells.

[PMO Gordo]

I finally got the molding procedures right! Unfortunately, none of the three fast-curing materials I tested can withstand the power of CO2: Alumilite regular resin, Alumifoam, and Foam 610. The problem is due to the thin walls of the base of the projectile, which require materials of greater tensile strength. The last material I can try is the Alumilite Performace 80D, which has a lot more tensile strength than others but has longer curing time.

I did try launching my projectiles with green gas, but the Matrix Eagle Force Multi-Purpose CNC 40mm Airsoft Grenade Shell - Short type I was using just didn't hold enough gas to propel the projectiles for long distance. I got about 20 ft with my Matrix grenade shells on green gas. It is possible to get it to work with long type grenade shells, but then it won't fit regular 40mm grenade pouches.

If the Performance 80D still won't solve the problem, I will have no choice but to go back to the drawing board. I probably will work on redesigning the projectile cap of the G&P Projectile Cap 40mm Airsoft Grenade Shell to include a chalk-filled tip. Although that would mean players will have to get the G&P grenade shells to launch my projectiles.

 

[PMO Gordo]

The strongest plastic still didn't work unfortunately. I even strengthen the cavity near the tip, but the material failure just occurred further down. By my estimation, the walls of the projectiles need to be at least 2 mm to withstand the power of CO2. The space between the typical grenade shell and the grenade launcher barrel is less then 1 mm, so the P.M.O.G 2.0 design does not work. Sorry to keep your hopes up.

However, this process from prototyping, manufacturing, and testing is not without merits. I've learned valuable lessons on how to create better copies than my early attempts at making P.M.O.G 1.0.

My next step will be strengthening the wall of P.M.O.G  2.0 and attempting to fit it to G&P Projectile Cap 40mm Airsoft Grenade Shells. I think it will still be possible to use regular grenade shells to launch this next version (I'll call it P.M.O.G 2.1), but the benefit of easy-to-carry will be lost.

Besides G&P Projectile Cap 40mm Airsoft Grenade Shells, there are other models that can be used to launch integrated projectiles. I'll list them below:
1. G&P Projectile Cap 40mm Airsoft Grenade Shell - $30 each on Evike (Evike.com Airsoft Guns - Airsoft Guns | Evike.com Airsoft Guns - Grenades & Mines |)

2. 'Vanaras' 40mm white star parachute gas cartridge - $32 each on RSOV (RSOV.com - Airsoft Gun & Tactical Gear Wholesale)

3. Madbull M576 Soft Foam Cap Grenade Shell - $68 each on Airsplat (Madbull M576 Soft Foam Cap Grenade Shell - Airsoft Grenade Shell - AirSplat.com - AirSoft Gun Warehouse)

4. 5KU-69 Airsoft 40mm Cartridge m433 HEDP - $31 each on EBairsoft (EbairSoft Airsoft parts & Tactical Gear - 5KU-69 Airsoft 40mm Cartridge m433 HEDP 5ku-69)

 

[PMO Gordo]

Just got the G&P 40mm Rubber Projectile Cap Type Airsoft Gas Grenade Shell. In the picture above, the G&P grenade shell with the projectile cap is on the left, and my P.M.O.G 2.0 is on the right. The 2.0 is currently sitting too loose on the grenade shell, so this picture is only for demonstration of what P.M.O.G 2.1 would look combined with the G&P grenade shell.

I was surprised to find the outer diameter of the G&P projectile is only 38 mm, which means the G&P grenade launcher barrel's inner diameter is about that size as well. The VFC EGLM barrel's inner diameter is 40.2 mm, so there's a discrepancy of the barrel sizes among different makes. This signifies the importance of the fins on my P.M.O.G 2.1 design. The fins on the P.M.O.G 2.1, similar to those on the Foster shot gun slug, are designed to help swagging the projectile down narrower barrels instead of spinning the projectile. The wall thickness of the G&P projectile is 1.5 mm, which is twice the thickness than my P.M.O.G 2.0. Shooting the G&P projectile with my Matrix Eagle Force Multi-Purpose CNC 40mm Airsoft Grenade Shell did not result in the destruction of the projectile, so I'm planning to use the same wall thickness on my P.M.O.G 2.1.

I also found a way to attach the G&P projectile to my Matrix grenade shell. I put a piece of paper tape, used for holding wound dressings in place, around the circumference of the projectile, and taped it to the grenade shell. The projectile was held in place fairly well as shown in the picture below. So, I figured it is possible to use the same trick on the P.M.O.G 2.1. And if players don't want to get the G&P grenade shells, they will still be able to use their current ones, although the total length of the projectile and grenade shell will be 50 mm more.


Here are a couple more pictures:
1. Matrix Eagle Force Multi-Purpose CNC 40mm Airsoft Grenade Shell (L) and G&P 40mm Rubber Projectile Cap Type Airsoft Gas Grenade Shell without the cap ®


2. The bases of the projectiles: G&P (L) and P.M.O.G 2.0 ®


3. The tips of the projectiles: G&P (L) and P.M.O.G 2.0 ®

 

[Erka92]

Awesome Work!

 

 

Hope it goes well because you have a potential buyer here!

[PMO Gordo]

P.M.O.G 2.1 prototype is on its way from Shapeway! In the mean time, I've been studying the characteristics of the G&P 40mm Rubber Projectile Cap Type Airsoft Gas Grenade Shell. I knew Evike marketed the G&P shell as green gas only, but I thought it had more to do with materials G&P used in making the shells. According to this article (link), the valve body (the purple part in the picture below) of a grenade shell would start to warp after repeated launch with CO2. The way to remedy that is to add a "valve buffer" (the red part in the picture below). The author recommended using a paintball gun buffer to make the valve buffer, but I found it difficult to get. So, I used a 70D sorbo sheet and cut it to appropriate size and shape. The bottom of the valve body can be used as guide when cutting the sorbo sheet.



After making this modification to the G&P shell, I felt that charging it with CO2 would less likely destroy the shell. However, after I charged the shell with unregulated CO2 pressure for 3 seconds , as I've always done with my Matrix Eagle Force Multi-Purpose CNC 40mm Airsoft Grenade Shell, I found it very difficult to press the discharge key at the bottom of the shell. I had to put all my body weight on it to discharge the gas. So, I looked for a maximum pressure the shell could take without freezing the discharge key. I found out that 550 psi is the maximum. Whether or not it will be sufficient to launch P.M.O.G 2.1 remains to be answered. Why the G&P shell froze up while the Matrix one didn't at higher pressure? My theory is that the Matrix shell has a bigger valve body, and it somehow prevent the discharge key from seizing at higher pressure.

Another reason I initially charged the shells with unregulated CO2 pressure was that I broke the regulator on my Madbull CO2 charger / regulator. When I inserted the CO2 cartridge, the pressure gauge would shoot straight up to 800 psi instead of staying at zero until I turned the adjustment knob. I found out later that the o-rings (#10 and #11 in the diagram below) were worn out. Fortunately, I still had the replacement o-rings that came with the charger, and replacing them fixed the problem.

[PMO Gordo]

Fig 1. P.M.O.G 2.0 and 2.2 base comparison (side view)

Fig 2. P.M.O.G 2.0 and 2.2 base comparison (bottom view)

Fig 3. G&P Projectile Cap Grenade Shell


Great news! The P.M.O.G 2.1 did hold up against CO2. Compared with P.M.O.G 2.0, the part of the base that goes on top of the grenade shells is narrower, but its wall is thicker. Still, at the beginning, I experienced difficulties with finding the right materials to use, and I almost gave up until I noticed the springiness of the G&P Projectile Cap that came with the grenade shell, which gave me the idea to try the Alumilite’s Performance 65D. The trick is to use tough but flexible materials instead of the toughest ones. Before using 65D, I was trying the 610 foam, Alumifoam, and Performance 80D, and they all shattered at the moment of launch. I also thought about using Alumilite’s Flex rubber series, but they take 24 hours to cure, which is way too long.

Fig 4. P.M.O.G 2.1 and 2.2 tip comparison

Video: P.M.O.G 2.1 and 2.2 Test
[video=youtube_share;n28uDDQ07Lc]

Fig 4. Matrix Eagle Force High Power Multi-Purpose CNC 40mm Airsoft Grenade Shell (Long Type)


I was also testing two sizes of P.M.O.G tips: one holds 20 grams of chalk, and the other 10 grams. The 20-gram tip produced larger cloud of chalk upon impact, but caused instability during flight. And while the 10-gram tip produced smaller cloud, its flight characteristics were better. My guess is that the larger tip moved the center of mass to the rear, which produced instability. It is possible to move the center of mass forward with the larger tip, but I’ll have to elongate the base. Further more, to maintain air efficiency a longer grenade shell like the Matrix Eagle Force High Power Multi-Purpose CNC 40mm Airsoft Grenade Shell (Long Type) should be used for the longer base. The increase size will probably make the proposed high capacity projectiles more suitable for Airsoft rocket launchers like the LAW and AT4. In any case, I’m content with the 10-gram tip, and will adopt it for the current P.M.O.G model.

There are some imperfection in the P.M.O.G 2.1 prototype: it is sitting 3 mm over the top of the G&P grenade shell, and the fins are 1 mm smaller than my original design. I fixed them with Dremel and some superglue. Coupled with the 10-gram tip, the new model is called P.M.O.G 2.2. I will begin mass-producing the P.M.O.G 2.2, and sending them to local shops and players for review in the next two weeks.