SpudFiles

hi!

Im starting to build a blowback gas operated airsoft smg, and i realized that hop-up would be nise. Im in the designing phase and i need an answer for one guestion: do the hop-up "detent" need to be on top or can it be in side?

I know this ia a stupid question but i need an answer

If it's on the side, the BB will curve to to side ...

but can i still get it go straight?

The man just said it would go to the side

The hop up slot needs to be on top. This makes the bb spin backwards and generates lift. If it is on the side, the bb will drop and go to the side.

A blowback airsoft gun sounds cool though...

what are you using for a barrel?

if you have a sloppy barrel/projectile fit, hop-up is (almost) pointless because your BB will already be inaccurate, due to air rushing around the side of the BB and making the BB "wobble" in the barrel.

If your BB wobbles, depending on how sever it is, the BB may hit the hop-up system at an angle, and fly of in a sideways curve.

I will edit in a few minuets with a drawing of a proper hop up for you.


EDIT:
black=barrel
dark gray=spring
light gray=bolt to changed tension
yellow=rubber type surface.
green=BB
light blue=air.

place this setup as close to the muzzle end of the barrel as you can.
(someone correct me if I'm wrong there.)

place this setup as close to the muzzle end of the barrel as you can.
(someone correct me if I'm wrong there.)

I think you are wrong there. It goes closest to the breech end of the barrel.

jhalek90 wrote:what are you using for a barrel?

place this setup as close to the muzzle end of the barrel as you can.
(someone correct me if I'm wrong there.)

I think you're wrong there. Every airsoft gun I've seen has the hop-up attached to the rear of the barrel, as close to the breech as possible.

jhalek90 wrote:place this setup as close to the muzzle end of the barrel as you can.
(someone correct me if I'm wrong there.)

Some arguments on the matter

well, the barrel is going to be 6.03mm tightbore so . But do i even need a hop-up?

well, the barrel is going to be 6.03mm tightbore so Very Happy . But do i even need a hop-up?

It depends, What is the power of the gun that you are making? Anything over 500fps doesn't need a hop-up but if you want to skirmish with it, you might need a hop-up to increase range and accuracy.

Well, what i can calculate, the gun will shoot over 500fps, so its not skirmishable . Well its going to be hammervalve operated blowback (pretty much the same blowback as in the jhalek90's 27mm blowback cannon has), and im going to feed it with co2, propably unregged. the air-reservoir is gonna me made from steel.

Thats why i wanted to put the jop-up in the side cause the air-reservoir is goint to be on top of the reseiver of the gun.

Jakethebeast, read this page.
http://www.spudfiles.com/forums/viewtop ... tml#316240

Well, what i can calculate, the gun will shoot over 500fps, so its not skirmishable

Sure it is... my airsoft gun shoots 650 fps with a 1/4" barrel, and with my 6.03 on the way, I'm sure it will be in the 700s. The only thing keeping it from being skirmishable in your case is that it probably isn't accurate enough.

Anything over 500fps doesn't need a hop-up

Anything over 500 fps needs hop up even more than anything under
The higher velocity will make the trajectory go berserk without hop up.

well, the barrel is going to be 6.03mm tightbore so . But do i even need a hop-up?

Absolutely, if at all possible. Read my link.

Anything over 500 fps needs hop up even more than anything under Laughing
The higher velocity will make the trajectory go berserk without hop up.

You think? I've shot multiple rounds at over 700fps all hitting the target through my scope. Just make sure your muzzle is smooth and has no bits of metal sticking out.

@warhead I don't mean to be rude but do you know what a hop-up is used for? Basically to increase the range an accuracy of an airsoft gun, a thin circle of rubber is placed at the breech of the barrel which puts backspin on the round. This backspin gives the the BB lift and gives the effect that it "floats" through the air at a straight tragectory(SP?) so it doesn't drop. This increases the range and accuracy. Hope this clears things up a bit

Yes, the spin increases accuracy not only because it goes further but also because it makes the bb spin in the same direction every shot, making each shot almost the same.