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Posted: Fri Jan 25, 2013 3:39 am
by DaxSF
Lol, I go to the gym
I don't need to exercise! Just kidding, adding some plates to the bench won't hurt anyone
Back on topic: LOL this is the exact same compressor I was going to buy! I actually wanted a compressor so there is an automatic charge, I hate manual pumping. The difference is only 10 PSI for the manual pump, and these kind of pumps cost well over $50 where I live, while the compressor costs more like $20..
Also I think the 6mm barrel will result in some major FPS incline because of the "snugger" BB fit (right now it just falls out of the barrel if I aim too low).
Posted: Fri Jan 25, 2013 3:46 am
by jackssmirkingrevenge
DaxSF wrote:The difference is only 10 PSI for the manual pump, and these kind of pumps cost well over $50, while the compressor costs more like $20...
On paper, you'd be right. But the reality is that these compressors are about as useful as a chocolate teapot, and will overheat and die long before they reach 250 psi.
A manual pump can also be used anywhere.
Also I think the 6mm barrel will result in some major FPS incline because of the "snugger" BB fit (right now it just falls out of the barrel if I aim too low).
Barrel tightness is *very* important. I did a test a
very long time ago:
2005 me" wrote:It's fairly obvious that the closer the barrel diameter is to the projectile diameter, the less air is wasted and therefore, more power. I decided to set up a simple experiment to see just how much of a difference it makes.
The basic setup was two 15 inch lengths of barrel tubing, one was aluminium with an I/D of 5mm, while the other was a straighted piece of coiled copper tubing with an I/D of 4.5mm. The barrels were hooked up to a blowgun attached to a compressor and used to fire lead BBs - with a nominal diameter of 4.5mm - at 100 psi through a chrony.
Over a 5 shot string, the 5mm I/D barrel averaged 242 feet per second, whilst the 4.5mm I/D barrel averaged 279 feet per second.
A projectile with 10% less diameter than the barrel resulted in 25% less energy, that is very significant.
Posted: Fri Jan 25, 2013 4:05 am
by DaxSF
MAN I love eBay! Just ordered some 6mm brass tubes since the smallest diameter I could find in this entire country was this 8mm and that was only because I found it from a scrap lamp post (go figure..)
Posted: Fri Jan 25, 2013 6:36 pm
by wyz2285
Incorporate a onboard shock pump would be a good option, but your chamber maybe too big to take advantage of the high pressure it offers.
Posted: Sat Jan 26, 2013 9:47 am
by iloveairguns
It seems to be a coax airgun... Plz take a pic from the front plz plz plz
Posted: Sat Jan 26, 2013 9:54 am
by DaxSF
iloveairguns wrote:Is it a coaxial airgun? just asking...
Yes it is.
After finishing this gun completely (probably next week, when all the parts arrive from eBay), I plan on making a new bullpup, semi-auto with a QEV I bought.
EDIT: Didn't see the edited post. I will take proper pictures tomorrow probably.. If you're interested in taking a look at the gun, PM me.
Posted: Sat Jan 26, 2013 10:01 am
by iloveairguns
Woah quick reply, well cool if your gonna make it a bullpup and a pic would be nice of the front, and what type of trigger system does it have? Is it the schrader type?
