Posted 02 April 2006 - 06:48 PM
Instead of having the plunger tube part of the bolt, which means that the plunger must be at least as long as the piston stroke just in front of the catch, I am using the gun body as the plunger tube. The bolt seals in the body with an O-ring and is worked back and forth by a metal rod the extends over the camber and barrel to a slot above the barrel. The bolt is only about 3 1/2 inches long and is made of a 1/2" PVC endcap and 3 layers of brass.
So far I have made the bold, plunger, chamber/barrel, magazine well, catch/trigger mechanism, and whatever you want to call the main body part thing.
Not bad for one day.
I still have to make the pump mechanism and the magazine, but I need a mag spring. Right now I am leaning toward a constant force spring from McMaster-Carr, but I'm open to suggestions.
Posted 02 April 2006 - 06:54 PM
My freind: You cant hit from there
Me:Yes i can... BANG(from my singled AT2K)
My friend:OOOWWWWW My arm.
Posted 02 April 2006 - 07:00 PM
Anyway, bullpup, eh? Hmm...not a bad idea.
Posted 02 April 2006 - 07:03 PM
Posted 02 April 2006 - 07:13 PM
As for the bullpup idea, mabey I wasn't clear, but this nerf gun will be a standard set up, with the magazine in front of the grip, but with the considerable length decrease caused by the new bolt and an extension spring between the bolt and planger you could potentially make a bullpup. That will probably be my next project.
Posted 02 April 2006 - 07:14 PM
Posted 02 April 2006 - 07:23 PM
Posted 02 April 2006 - 08:02 PM
29", for me, is really short. I'm used to homemades longer than 34". My next one has a micro (as in...7" long) barrel with an overall length of somewhere around 41", not magazine fed, but single shot. Then again, there's a silencer on it that is 12"...
Posted 03 April 2006 - 06:01 AM
Alias Scoped loser (+)
"In a sense, what I'm saying is that you shouldn't waste your time handling your balls. Go for the foamy rods instead."
Posted 03 April 2006 - 10:52 AM
Magazine rebuild kit
If you don`t want to go that route then it is going to be tough to find a spring with enough displacement to function as a magazine spring. At least tough to find one just laying around or at a hardware store. Coil springs, like the one I used in the FAR, work well. Finding them can be tough too. If you can find someone in retail that can get you one from a new or broken fixture. Thats how I got mine.
Good idea you have going on for your gun. I found it hard to design the action so that the section of the receiver where the plunger lies would have no holes, slits, or cuts in it. The operating rod sticks out of hte bolt and through the receiver which meant a long cut down the axis of the receiver. Because of this slot if I didn`t have the plunger tube as part of the bolt all the air would just rush out of the slot. I`m sure there are ways around that. You are right it does add another plunger stroke length to the length of the rifle. I didn`t have a whole lot of issues with that though. The distance from the stock to the pistol grip (length of pull) is dicated by comfort and turned out to be longer than the action needed. The magazine can be placed jsut ahead of the pistol grip allowing suitable distance from the trigger. Magazine placement will dictate chamber placement and beyond that is just barrel which can be whatever length you want. I took all these points into consideration when making hte SCAR. The LOP is as short as I felt comfortable and is still longer than the action needs. I had to perch the spring up about 2 inches from the end of the stock to get fiull compression. I placed the magazine much closer to the grip than on the FAR and the magazine is much shorter. The barrel is shorter at 12". The whole rifle is about 29" with the brake on the muzzle.
I don`t know if you are planning a rifle or not. If you use the system you have going you can drop the stock and make a pretty wicked pistol thing. That would be pretty cool.
Posted 03 April 2006 - 01:54 PM
To solve the problem of no slots in the reciever where the plunger is, I'm using two metal rods side by side that go up the inside of the body passing right above the chamber and apearing through a slot cut above the barrel.
I was planning on making this a rifle, but it is so short behind the magazine that it may end up with a shortend barrel as a pistol. The next version will use a locking bolt and an extension spring between the bolt and plunger. This should give me the extra two inches less of length that I need to make this thing a bullpup.
Posted 03 April 2006 - 05:52 PM
EDIT: Actually, looking at your design, you might need a second o-ring on the endcap at the end of your bolt. Otherwise, when you push back the bolt with your bolt handle, the force on the spring might cause the bolt to "twist" in a sense, making it alot harder to push the bolt and plunger back, as well as causing possible problems when the bolt comes back to seal the dart/shell. Of course, that's just what I see, I haven't tested it myself.
Edited by ompa, 03 April 2006 - 10:50 PM.
Posted 04 April 2006 - 04:44 PM
Ompa- I just tested the new bolt with the bars and there is no twisting whatsoever. This must be baecause the bars are so close to the inside of the pvc and are in fact rubbing along the top of the chamber, which is made of the same size brass as the back of the bolt where the bars attach.
Also, I've decided on the issue of whether this will be a rifle or pistol. It will be neither but instead it will be a submachine gun type thing, with a folding stock and possibley a shorter barrel.
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