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hop-up

Unread postPosted: Fri Oct 19, 2007 5:04 pm
Author: ALIHISGREAT
would putting a line of small holes along the top of my barrel put backspin on a bb, the holes would probably be around 1cm or less apart and would be in the last 20cm of the 80cm long barrel.

Unread postPosted: Fri Oct 19, 2007 5:10 pm
Author: e1337
I really don't know, I think it would due to drag, but you might lose power.

Peace,
e1337

Unread postPosted: Fri Oct 19, 2007 5:36 pm
Author: Hubb
I've thought about this, too (only for paintball). The best way I've figured it would be to put a small laceration into the top of the barrel, near the breech. Then obtain o-rings to fit in these slits and place the o-ring in such a way so that part of the o-ring is actually in the barrel. I've included a diagram to help better understand it.

Unread postPosted: Fri Oct 19, 2007 5:43 pm
Author: ALIHISGREAT
so that would work because of friction between the bb and the o-rings? so the o-rings would wear over time.

Unread postPosted: Fri Oct 19, 2007 5:50 pm
Author: Hubb
The o-rings probably would wear over time, which is why the o-rings should be replaceable.

Unread postPosted: Fri Oct 19, 2007 5:59 pm
Author: ALIHISGREAT
hmm could get fiddley in a 6mm barrel, i would prefer using my idea (if it works) because it would act as a silencer too because my barrel will be inside some 15mm pipe.

Unread postPosted: Fri Oct 19, 2007 6:22 pm
Author: Hubb
Yeah, it may be hard to accomplish using that size barrel. However, your idea seems more like normal porting. I don't know how effective it's going to be in creating hop-up. It may work, but I don't know.

Unread postPosted: Fri Oct 19, 2007 7:34 pm
Author: Marco321
Just put a trin strip of rubber at the top of the barrel, it will create backspin, thats how its done in airsoft i believe.

Unread postPosted: Fri Oct 19, 2007 10:42 pm
Author: noname
Your idea will most likely not work, and drilling small holes in small diameter metal pipe is a [female doggy]. All you need to is cut a tiny slot in the end of your barrel (perpendicular to end of barrel, about 1 cm from the end) and put an O-ring in it. It works great, and replacement O-ringas are only like $0.10 at that size.

Unread postPosted: Sat Oct 20, 2007 3:23 am
Author: ALIHISGREAT
noname wrote:Your idea will most likely not work, and drilling small holes in small diameter metal pipe is a [female doggy]. All you need to is cut a tiny slot in the end of your barrel (perpendicular to end of barrel, about 1 cm from the end) and put an O-ring in it. It works great, and replacement O-ringas are only like $0.10 at that size.


well i'm gonna be drilling holes anyway becasue i'm gonna suppress it so i was just wondering if the postition of the holes affected the spin on the bb.

and if i was to put a strip of rubber along the top of my barrel how long would it need to be and if the barrel was a tight fit would tape work?

Unread postPosted: Sat Oct 20, 2007 3:55 am
Author: jackssmirkingrevenge
Why bother with hopup slowing the BBs down when you could just aim higher?

Unread postPosted: Sat Oct 20, 2007 4:04 am
Author: ALIHISGREAT
jackssmirkingrevenge wrote:Why bother with hopup slowing the BBs down when you could just aim higher?


it would make the gun more accurate because it would counteract any spin put on the bb becasue of imperfections in the barrel.

although i could just use a tissue sabot to do this.

however i will be drilling holes anyway so i thought that they could have a second use.

Unread postPosted: Sat Oct 20, 2007 4:11 am
Author: jackssmirkingrevenge
it would make the gun more accurate because it would counteract any spin put on the bb becasue of


Would it?

As far as I know, the whole point of hop-up is to give BBs an upwards spin in order to flatter the trajectory, to compensate for projectile drop which is more evident in BBs due to their very poor ballistic co-efficient. Since you'll be firing "heavyweight" BBs at much higher velocities than normal BB guns, I wouldn't bother.

imperfections in the barrel


What on earth are you using for a barrel then? Sheep intestines? :D

Unread postPosted: Sat Oct 20, 2007 4:44 am
Author: ALIHISGREAT
no... not sheep intestines aluminium tube but there will probably be imperfections becasue its not designed to be super smooth and perfect i assume although i'll have a look later when i buy it, and i want hop up to give awsome range and accuracy.

no one has answered my qustion though, would the porting along the top of the barrel put backspin on the bb or not?

Unread postPosted: Sat Oct 20, 2007 4:49 am
Author: jackssmirkingrevenge
i want hop up to give awsome range and accuracy


Chances are that without adjustable hop-up, you're never going to be able to tweak it to get that - I say stick to no hop-up and make a range table to compensate for BB drop.

I wouldn't worry about imperfections - I don't know what sort of tubing you're buying but the ali tube I've found has always been perfectly smooth on the inside.