HP/low volume vs. LP/ high volume in relation to accuracy

[Gun Freak]

For my upcoming coaxial airsoft sniper, the chamber can either be 1.25" and I could use low pressure or it could be 1" and I would use higher pressure. The construction will be PVC but I will happily take it to 150 or higher psi. Either way, the airsoft barrel will be inside 1/2" pvc which the piston will seal on. So I am wondering if I go with the higher volume, there will be a bad muzle blast and veer the bb off course or if high pressure low volume is the way to go. What are your suggestions?

[clemsonguy1125]

I dont suggest using 1/2 inch pvc in either, I used CPVC in my stich gun in a coax with a 1 inch chamber. It fine on that but with 1/2 inch PVC you will have small chamber volume. Your best choice is probably 3/4 inch EMS electrical conduit pipe with a 6mm barrel. Your getting a high pressure pump arent you? It not much more expensive than pvc. If forced to choose id say the 1.25 inch pipe though.

[jackssmirkingrevenge]

High pressure low volume is the way to go - you want the highest possible muzzle velocity to help with accuracy.

If you're worried about muzzle blast, fit a muzzle brake/air stripper/suppressor

[Gun Freak]

@Clemsonguy, I dont need a big chamber volume, my barrel is only 3 feet of 7mm pipe.

@Jack, So the best way to go is the 1" chamber, and I have plans to make an integral suppressor at the last maybe quarter of the barrel, just some hoels drilled and wrapped with something to suppress it (suggestions?). Here is the mock muzzle break that fits over the 1/2" barrel...

You can probably guess what gun it is modeled after now

[clemsonguy1125]

So is this for skirmishing, or plinking, if its for skirmishing your probably good, but if you want 500FPS+ you probably want to use metal because 150PSI isnt really high pressure.

[Gun Freak]

I was thinking more in the neighborhood of 200 psi, it is for both plinking and skirmishing, and don't tell me it will be impractical for that, because I have already thought it through and you would be amazed at my airsoft tactics. You should have seen me last night ROFL. I think 500 fps is way less than I will be getting with this thing, especially on higher pressure. Let me run it through GGDT real quick.

[Technician1002]

I do know that a lot of excess muzzle blast tends to tumble t shirts very early in the launch reducing accuracy and range. I'm not sure about spheres. For power low volume and high pressure is the norm for acceleration of the small diameter rounds.

[Gun Freak]

Good, HP/ low volume it is.
Here is the GGDT on 100 psi. 200 psi yields over 1100 fps, lol.

[jackssmirkingrevenge]

It's the 0.236" projectile in a 0.250" diameter barrel which concerns me in terms of accuracy, think of the golfball in a drainpipe analogy - you never know which direction it's going to come out of the barrel...

[Gun Freak]

True. I shall check a hobby shop for some 6mm pipe, but I don't know if I will be able to get it in a long section. The diameter is actually .2811 for the barrel GGDT doesn't calculate for blow-by does it?

[jackssmirkingrevenge]

You don't need a long section, really if you just have the last 2-4 inches of the barrel that are a true 6mm diameter then you're good in terms of accuracy.

[Gun Freak]

That doesn't seem like it would work though. The bb could run into the edge of it...
The bb (green) shoots down the 7mm pipe (blue) then when it gets to the 6mm pipe (orange) it would hit the edge of it and slow it down.... if it even makes it out the barrel.

[jackssmirkingrevenge]

chamfer the edge of the tube and you won't have any problems, besides don't forget that the BB is already riding centrally on a "tube" of air...

[jhalek90]

gunfreak, the easiest way i found to get a barrel, is go to wall-mart.. and get an airsoft shotgun for around 10 bucks.

you will get a barrel, a hop up system, and a few bbs.... as well as any parts you save from the shell of the shotgun, aka grips, pump....

well worth the 10 bucks.... even just for the tight bore airsoft barrel.

[Gun Freak]

chamfer the edge of the tube and you won't have any problems

Are you sure that would work, how long would the piece of 6mm pipe have to be, just a couple inches or like a foot?

besides don't forget that the BB is already riding centrally on a "tube" of air...

That kind of contradicts what you said earlier, unless I am missing something, I probably am

think of the golfball in a drainpipe analogy - you never know which direction it's going to come out of the barrel...