biged
Master sergeant
Posts: 468
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Post by biged on Apr 14, 2008 5:50:52 GMT -5
Designation: M1A1 replica Construction: Steel, Oak, PVC Type: Pneumatic Bore: 2.625 Pressure range: 50-290 psi FPS: 300 (@120psi) Hopup: Yes Range: 175' (direct fire) Chambering: Sliding Breech Valve: 2" piston, 1.5" porting ROF: 4-6 RPM Ammo: Tennis balls Designed to be shot at buildings and vehicles. It's loud, and can break ribs under 50'. At 75 feet you can catch the tennis ball with your bare hands and is safe. At 125' it drops off. With 15 degrees of arc you can reach 175'. Anything you hit with it has a loud report, it's unmistakable. If you were in a plywood bunker it sounds like someone hitting the outside with a bat. More pressure, greater range. If I add a ball valve instead of a blow-gun to vent the pilot volume, I am limited to PSI equal to the rating of the hose - 290 psi. Configuration from the Testing phase. (grip and stock not connected) Plumbing. Carving. Steel backbone & plumbing. The world's largest hopup. (As far as I know.) Completed stock. Another recent mockup. (grips and stock not attached) Completing the trigger assembly sometime this week. ///ed///
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TommyGunner
Staff Sgt.
Hackjob Mauro
1st Marine Division, 1942
Posts: 2,265
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Post by TommyGunner on Apr 14, 2008 7:29:45 GMT -5
This is fantastic, you have yet again out done yourself. The break ribs at 50ft seems a bit iffy to me. But then again its probably less dangerous than having something like a vehicle in a game where the possibility exists that a person could get run over and killed.
TommyGunner
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click
Sergeant
Company G, 3rd Battalion, 1st Marines, 1st Marine Division
Posts: 1,764
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Post by click on Apr 14, 2008 8:46:04 GMT -5
Break ribs at 50 feet? Isn't that a little dangerous? Looks good though...
Click
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Ersatzjack
Corporal
"That silly Franz... he thinks we are winning."
Posts: 1,093
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Post by Ersatzjack on Apr 14, 2008 16:27:06 GMT -5
It's not the breaking ribs at 50-feet that I'm worried about but the energy at oh... let's say 5-feet. Best left in the hands of a responsible person for sure. Looks like you have a very nice counter to the airsoftcorner.com tank going there. You know of course that you'll still have to hit the trackster (er.. uggh I mean Panther) in the side or rear to take it out though, right?
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biged
Master sergeant
Posts: 468
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Post by biged on Apr 15, 2008 4:56:27 GMT -5
Under fifty feet is the is the danger zone at 120 psi.
That's 234 Joules of force with a 56 gram tennis ball. A .25 gram bb at 400 fps has 1.86 Joules.
Because a Tennis ball is so light the diminishing range effect takes over by 50 feet. At 125-175 you can almost step out of the way of the tennis ball. It appears to be traveling in slow motion at that point. The Hopup or "Magnus Effect" on a Tennis ball is really wild to see.
I would never shoot it directly at a person unless they had a baseball glove and were far away.
Historically accurate and more challenging, I love it.
///ed///
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biged
Master sergeant
Posts: 468
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Post by biged on Apr 21, 2008 5:15:14 GMT -5
3 grip designs later... 2 Steel plates drilled & tapped to the blow gun. The plates will be welded to the tube. The Oak grips will be screwed to the plates. The front sling ring plate will also be welded to the bottom of the plates. ///ed///
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YankeeDiv26
Staff Sgt.
Frustrated Mac Owner
BDM<33
Posts: 2,462
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Post by YankeeDiv26 on Apr 21, 2008 7:01:54 GMT -5
Wow. That is friggen sweet! As a labor of your hands Ed, I wouldn't expect anything less.
<YD>
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Post by Garrick Udet on Apr 21, 2008 10:45:50 GMT -5
Ed, you charging this with CO2 or HPA?
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biged
Master sergeant
Posts: 468
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Post by biged on Apr 21, 2008 17:37:50 GMT -5
CO2 regulated to under 120 psi. I have a palmer's air rig. But I just picked up another air rig. www.lowes.com/lowes/lkn?action=productDetail&productId=166441-61735-J-6901-100The regulator and CO2 bottle will be hidden in a ammo bag or musette bag. The blowgun (trigger) can handle as much as 150 psi. If I change the blowgun (trigger) to a ball valve I can go as high as 290 psi which is the max pressure rating of the black hose. If I switch the tubing to hydraulic steel tubing or HP air lines I can go as high as 1000-3000 psi. I won't however go any higher than 150 psi. There is no need for it. ///ed///
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Post by schmitty on Apr 21, 2008 21:27:21 GMT -5
Wow That is really cleverly built. Nice handy work as usual. There isn't room to fit the tank and regulator within the bazooka? Is the diameter too big? Schmitty
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biged
Master sergeant
Posts: 468
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Post by biged on Apr 22, 2008 4:06:28 GMT -5
Haven't measured one yet. It is a possibility, but the breech that slides open is the heat shield. The last 16 inches beyond that is chamber and piston.
It can be gassed up then disconnected from the air source to give a stand alone look & feel. Once the ball valve in the stock is closed the line can be disconnected. If you open it slowly with no tank attached you can safely vent all the pressure inside the gun without firing it.
The chamber itself is around 64 cubic inches. So two 12 gram CO2 cartridges could be used to charge it up 120 psi. I would have to add a shrader valve and use CO2 tire inflater for that setup.
I am also predicting about 8-10 shots from a 9oz CO2 tank at 120 psi. If it's real hot outside maybe 12 shots.
///ed///
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Post by Garrick Udet on Apr 22, 2008 15:21:04 GMT -5
There are also the really rare, old school paintball 4oz CO2 tanks. I've only ever seen a couple, mostly now used by old timers as expansion chambers. Based on the diameter of pipe you're using, I bet you could fit a 9oz CO2 in there nicely with a small inline reg. It would just mean shortening the barrel a bit.
Nice work!
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Post by Warlord on Apr 25, 2008 17:11:12 GMT -5
Aaanndd thats why we're getting rid of the facades ...Wow...fantastic job Ed. Cannot wait to see it in action.
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biged
Master sergeant
Posts: 468
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Post by biged on Apr 26, 2008 5:33:41 GMT -5
I welded the grip and stock onto the tube. Then did a test fire, and the shot only farted out.
I ran some numbers and calculated the pilot volume increase by x4 times. The original volume is around 3 cubic inches. After I added all the tubing & gauge that increased to over 11.87. That means the valve is opening very slowly like 4 times slower than normal and hence the 30 foot fart shot. The faster you open a valve (speed in milliseconds) the more power you get.
I ended up putting a 1/4" QEV (QuickExhaustValve) on the back of the bazooka which increased the speed better than just a blowgun. The bazooka operation is still the same, it just has a small valve on the back cap. I should be able to camouflage it with the back cage of the bazooka. I'll post a picture of it soon.
///ed///
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Post by gunfighters on Apr 27, 2008 13:30:05 GMT -5
"That's 234 Joules of force with a 56 gram tennis ball" ummm thats a bit more then "rib breaking" for refrance a study by U.S. Army Land Warfare Laboratory on blunt trauma found 40.67+ joules to be “dangerous” IE “broken ribs, concussions, loss of the eyes or superficial organ damage” 122+joules is listed as “Severe Damage” ie “massive skull fractures, rupture of the heart and kidney, and fragmentation of the liver” as a side note Within the nonlethal community, it is generally accepted that any impact exceeding 58 foot-pounds(78.6J) of kinetic energy: will result in a potential fatality. as such most riot controal rounds stay below the 78.6J mark.. with that in mind 234J is a bit exissive great build btw, cant weight to see it finished up and detailed
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biged
Master sergeant
Posts: 468
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Post by biged on Apr 27, 2008 13:50:56 GMT -5
Welcome aboard gunfighters... My initial muzzle velocity of 300 fps was chronographed before I made it a breech loader, and added hopup. I will chronograph it again next weekend. The power loss of the shot is truly incredible, beyond 75 feet you can easily catch the tennis ball. I did manage to complete the basic build of the bazooka, and test fire it several times. Finished the front hand guard and I made a removable shroud to cover (and protect) the rear QEV. Side note: The QEV turned the gun into a semi-auto cannon. I can leave the gas on (red lever on stock) and every time you pull the trigger the gun will fire. ///ed///
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YankeeDiv26
Staff Sgt.
Frustrated Mac Owner
BDM<33
Posts: 2,462
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Post by YankeeDiv26 on Apr 27, 2008 14:26:41 GMT -5
wow. Semi-auto gas charging. SWEET.
I'm assuming sights/finish work are to follow?
<YD>
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biged
Master sergeant
Posts: 468
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Post by biged on May 1, 2008 16:41:45 GMT -5
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YankeeDiv26
Staff Sgt.
Frustrated Mac Owner
BDM<33
Posts: 2,462
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Post by YankeeDiv26 on May 1, 2008 17:23:29 GMT -5
She's a beauty. Awesome job Ed.
Tribal Wars right?
<YD>
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biged
Master sergeant
Posts: 468
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Post by biged on May 4, 2008 5:01:52 GMT -5
Yes. Final head count was 190. Really crummy weather, 43, rain and windy. I ended up test firing it about 80 times. Range was the same 175-200 feet. Piston had trouble resetting towards the end of the day, most likely because of the chilled CO2. I missed the opportunity to chronograph it. I will do it on Monday or Tuesday.
///ed///
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deacon
Private 1st Class
Posts: 748
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Post by deacon on May 4, 2008 22:42:47 GMT -5
are you thinking about selling them?
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biged
Master sergeant
Posts: 468
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Post by biged on May 5, 2008 4:41:12 GMT -5
There is a chance I may sell them. But it's not a toy. Two or three shots in a residential neighborhood and someone would call the police. It will break car windows and dent side panels under 50 feet.
Believe it or not the hardest part about making it was attaching the wood stock and front grip. It took at least 6 hours from cutting the oak, until it was on. Producing just the tube, piston, chamber and barrel, I could bang out in 2 hours. Plumbing takes less than 20 minutes.
///ed///
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Ersatzjack
Corporal
"That silly Franz... he thinks we are winning."
Posts: 1,093
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Post by Ersatzjack on May 5, 2008 7:58:36 GMT -5
When is the Panzerschrek version coming out? ;D
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Post by 2ndranger on May 5, 2008 8:33:51 GMT -5
Very nice job Biged!
Franz
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Young Blood
Corporal
Dog Co. 504 PIR, 82nd Airborne (SoCal)
Posts: 876
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Post by Young Blood on May 5, 2008 13:38:47 GMT -5
yeah that thing looks brutal, I would definatly hate to be a victim..!! -Eddie
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biged
Master sergeant
Posts: 468
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Post by biged on May 10, 2008 6:32:17 GMT -5
Ersatzjack, I started gathering Panzerschrek photos. I already built a couple extra sets of internals. The one on left is a 2 piston with 1.5 porting. The same size as the bazooka. The one on the right is a 3 inch piston with 2.375 porting. It is more powerful than the 2 inch. Which means less air volume to launch a ball the same distance, just more shots per air source. Example: Instead of 120 psi I could go 90 psi and get the same distance. I chronographed 20 shots in it's finished configuration at 120 psi. 122 234 192 121 233 249 259 242 235 237 244 121 220 231 237 232 242 317 220 255 ----- 222.4 Average fps after 20 shots, which is still a dangerous 128.27 Joules with a 56 gram ball. I did record 2 inaccurate readings of 4 and 1040 fps. ///ed///
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Post by trippy on May 10, 2008 10:13:17 GMT -5
Are you doing this with the fuzz on the tennis ball? It dramatically increases surface area, slowing the ball down faster, and thus reducing range. If you remove it, you can get much more distance, or lower the muzzle velocity and still get the same range with less danger.
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biged
Master sergeant
Posts: 468
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Post by biged on May 10, 2008 10:53:56 GMT -5
I fired it a couple times at 150 psi, which put a ball out to the 225-250 (guess) foot mark. The tennis balls lose fuzz after every shot due to the hopup. The fuzz can be seen floating through the air. The tennis balls look distressed more and more after each shot.
It is very difficult to visualize the magnus effect (hopup) from the side. But the balls speed slows down incrementally. When standing at the 200 foot mark, your first instinct is to jump out of the way, but, the ball just "dies" and drops to the ground with very little forward momentum. The benefit is a, level, straight shot, which is amazing to watch. Depending on how "new" the ball is you can see it rise in it's flight similar to over-hopping a bb.
If I seat the ball straight in the chamber you could easily hit a outhouse sized target at 175 feet. I did experiment with wrapping tape around the center of the ball so the ball would self correct it's flight path. But, the tape gets blasted off the ball and floats to the ground 2-3 feet from the muzzle.
///ed///
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Post by Gordak on May 10, 2008 12:59:53 GMT -5
I got to shoot this thing, it was ammazing, I just hope no one gets hit with it Actually I think if it shot larger nerf vortex style rounds (IE no ho up), it would be safe, and VERY accurate, Just my thought. -Gordak
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on May 10, 2008 13:12:18 GMT -5
It looks awesome and as a device for bunker busting and anti vehicle it sounds ideal. I heard great things from friends who were present at the event and would remind you that the sudden lack of inertia and dramatic drop is exactly what an airsoft Bb does at the end of its flight.
It's why folks believe they are hitting their opponnents at ranges that simply aren't being achieved. Cool weapon. I do think you could sell them.
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