New QEV Rifle
Posted: Tue Oct 23, 2007 1:28 am
After building my first gun around my newly purchased QEV and whatever parts I had lying around I set out to construct something a little better.
My main focus was to reposition the main chamber and decrease the pilot volume, as well as relocating the exhaust valve.
I went to the store and purchased the components I needed, surprisingly the stainless steel fittings (very nice IMO) were about the same price as the brass, so I decided to use them.
I only used a brass end cap because it was easier to drill through, and I don't think there were stainless steel screw in barbs. The stainless steel, as well as not rusting, is also a lot harder, which means the threads will take a bit more abuse then the brass would.
I'm not sure exactly what type of tube I used, but it's high spec and can easily hold a lot of pressure, as well as looking pretty mean.
The schrader valve I got for free from a tyre/wheel place. I couldn't find a fitting that it screwed into so I just drilled a hole in the cap and used the nuts it came with to hold it in place, it seals ok, no obvious leaking.
The barrel is the same one as on my last one, rather thin walled aluminum tubing. The wall thickness is only 1mm which I think is a little too thin, I would like something a little heavier.
I had to use the same method of attaching the QEV to the barrel as last time because I couldn't think of a solution at the time, it's all good though. Its reasonably strong and doesn't leak.
The ball valve is really smooth to open and close although it still puts off my aim when firing the thing.
I usually take it up to around 170-180 psi using my air compressor. I think the only thing limiting it is where the tube is pushed on to the barbs.
Although they would probably hold to a lot higher pressure, the air compressor has a similar setup using that type of tube and barbs, so if the gun doesn't go then that will (or the crappy tyre filling device will, I go off the scale on it's built in pressure gauge).
Specs:
-The barrel is 1m long with a 10mm internal diameter (0.4 inch)
-The chamber is the same as the last one, about 400ml I would guess.
-QEV is 3/8 inch variety
Pros
-The QEV works a lot better with a small pilot volume, it goes off with a bang and you feel the recoil.
-It's compact.
-Reasonably powerful for it's size I guess.
-Can take high pressures. (High for what I'm using)
-Triggers well, using a ball valve seems to work nicely.
Cons
-Difficult to aim without a stock to keep it steady.
-Moving the ball valve puts my aim off.
-No safety, can be accidently set off when removing the filling thing from the schrader.
-Has to be muzzle loaded.
I will eventually come up with something that rectifys these problems.
Now some pictures.
My main focus was to reposition the main chamber and decrease the pilot volume, as well as relocating the exhaust valve.
I went to the store and purchased the components I needed, surprisingly the stainless steel fittings (very nice IMO) were about the same price as the brass, so I decided to use them.
I only used a brass end cap because it was easier to drill through, and I don't think there were stainless steel screw in barbs. The stainless steel, as well as not rusting, is also a lot harder, which means the threads will take a bit more abuse then the brass would.
I'm not sure exactly what type of tube I used, but it's high spec and can easily hold a lot of pressure, as well as looking pretty mean.
The schrader valve I got for free from a tyre/wheel place. I couldn't find a fitting that it screwed into so I just drilled a hole in the cap and used the nuts it came with to hold it in place, it seals ok, no obvious leaking.
The barrel is the same one as on my last one, rather thin walled aluminum tubing. The wall thickness is only 1mm which I think is a little too thin, I would like something a little heavier.
I had to use the same method of attaching the QEV to the barrel as last time because I couldn't think of a solution at the time, it's all good though. Its reasonably strong and doesn't leak.
The ball valve is really smooth to open and close although it still puts off my aim when firing the thing.
I usually take it up to around 170-180 psi using my air compressor. I think the only thing limiting it is where the tube is pushed on to the barbs.
Although they would probably hold to a lot higher pressure, the air compressor has a similar setup using that type of tube and barbs, so if the gun doesn't go then that will (or the crappy tyre filling device will, I go off the scale on it's built in pressure gauge).
Specs:
-The barrel is 1m long with a 10mm internal diameter (0.4 inch)
-The chamber is the same as the last one, about 400ml I would guess.
-QEV is 3/8 inch variety
Pros
-The QEV works a lot better with a small pilot volume, it goes off with a bang and you feel the recoil.
-It's compact.
-Reasonably powerful for it's size I guess.
-Can take high pressures. (High for what I'm using)
-Triggers well, using a ball valve seems to work nicely.
Cons
-Difficult to aim without a stock to keep it steady.
-Moving the ball valve puts my aim off.
-No safety, can be accidently set off when removing the filling thing from the schrader.
-Has to be muzzle loaded.
I will eventually come up with something that rectifys these problems.
Now some pictures.
