Original Thread
There were a few initial issues that needed to be addressed:
-It was too heavy
-The magazine went too high into the sightlineing the sprinkler valves and the pressure drop was significant enough to only get a few shots per fill…far too inefficient for what I wanted.
-It was both too big and too long. I wanted a bull pup assault rifle not an unwieldy piece of plastic that weights 27 pounds fully loaded.
So yesterday I got my first day off in 2 months so I sat down and began to build a rifle which is going to own its predecessor in ammo capacity, air chamber volume, ergonomics, and overall intimidation factor. This is what I've come up with thus far. Mind the crappy pics, 0.3 Mpl webcam.
The body is 1 1/4 conduit pvc (only place that sells SCH40 does so at a plumbing store parts counter and its not cheap, also it doesn't need to be pressure rated for my application.) You might notice I salvaged most of the parts from the original reaper and so far I've only spend 10 dollars on new material.
Behind the mock trigger is a sprinkler valve which has its solenoid removed while I build but I'm keeping it electrically actuated for a sweet trigger set-up I have in the works. The regulator isn't easily seen in the picture, but it is sitting behind the sprinkler valve, which leads to a tee to a 0-200 pressure gauge and to the main tank that is 14x2inch SCH40 pvc. attached to the front of the chamber is a brass tee where another brass tee comes off of that where a L-shaped piece of 1 1/2 SCH40 Pvc is attached, as well as a schrader valve (labeled a "snifter valve" at homehardware) there is another 1/4 inch hole which is cut off with a simple 1/4 threaded brass plug. On the very end of the 1 1/2 L chamber there is a ball valve which is simple there so I don't have to dump air through the sprinkler valve (I broke off the black lever-it still works but no manual dump anymore.)
I'm using the same shells as the Mk.1 however I initially wanted to use 3 inch shells. This made a great
deal of dead space in the finished product. So cutting down to a 1.5 inch shell meant I could cut down a lot of dead space and bring the new rifle from 37 inches to hopefully something around 28-32 inches while keeping its 14 inch barrel.
The bolt still needs to be finished as its made of 1 inch aluminum round stock pipe with 3/4 inch pvc conduit inside that the shell will fit into and rest against the pieces of 3/4 aluminum (grey in the pic beside the white CPVC.) I also didn't like the ease of the charging handle in the original reaper so I switched to a polished stainless steel handle that I happened to have lying around that will be perfect to use.
Bolt detail
Bolt charging handle
With more people using shells these days in their homemades I'm surprised linear magasines havent caught on more. OMPA make a working prototype in his NEAR, and Torque used one in his Boomstick.
This is the Original linear rotating mag that completely killed my sightline however looking through the centre was somewhat helpful but I wanted better!
It is made of 1/2 sch80 pvc which fits my shells with just enough room to slide. There are 10-11inch pipes around a 2 inch piece of 2in SCH40 pipe which has a 1-1/4 coupler hotglued inside. This makes it possible to have an unobscured sightline and increase the ammo capacity from 42+1 to 60+1! *edit* I made a mistake in measuring. I can fit 7 shells in each pipe, so the capacity is 70+1 but I'll be cutting that in roughly half in my design change.
So I need to finish the bolt and some minor fitting work before I can bondo this sucker and give it some looks (I want P90 meets alien vs. predator)
Questions/ Coments are always welcome and I'll post more as I find more time to work on it.
FA.
Edited by FromAbove, 21 August 2006 - 09:02 PM.
