tanktrack

hi folks.....

just stripped the turret on my hl tiger to rotate and lengthen the barrel...

found a hole drilled into the side of the barrel.... are they all like this and if

so anyone know why ... cheers

martin g

Is that the inner barrel ? i mean the metal not the plastic?

I dont know if this is normal or in other tanks. but..what i can tell you being a former small arms technician is that some novelty air weapons ( and indeed some true weapons) have holes like this in the barrel to reduce the velocity or to vent propellant gases back to the reloading mechanisms). That is probably in this case to make it safer, meaning the propellant gas (air in this case) behind the projectile relieves here, rather than at the muzzle thus reducing the force behind the round and therefore the velocity. I have never inspected the air soft gun but i assume is uses air in this way. In summary, if the hole wasnt there, the round (BB) would have more 'push' and therefore more velocity, it would travel faster and further. I am not sure I should be announcing this on reflection.....heck i will. If i am right, solder over the hole, make sure there is no residue inside the barrel, and your gun will be more powerfull providing it made well enough, if the gun isnt strong enough..youll blow the gun seal and it will be kaput!

I shoud write a disclaimer now maybe..? I should also add that this it what it APPEARS to be from the pic, i couldnt be sure without seeing it myself.

tanktrack

Cheers martin... what you have stated is partially what i was thinking
but you explained it a lot better... shall def close the hole up and see
how it goes

tanktrack

ps it is the inner barrel .... a possible safety feature ???

martin g

Yeh i would say so, simply reducing the gun power basically, think of it as the reverse of your vacuum cleaner and the little opening on the tube, the sliding one, when you open it it reduces the suction. Opposite applies, air pressure behind the projectile is relieved early to reduce the force. They will have fume extractors next!

schutzstaffel

guys ..guys ..

slow down..[sm=omg_smile.gif] good ideas but,

that hole is for stopping the suction effect while the bb travels in the barrel.
it increases the power of the gun,
with out it ,
the bb would slow down at the end of the tube because of suction behind the bb.

a member here have notice a small increase of power with drilling a 2 hole.
but where??can`t remember where ,read old post about air gun.

but the real secret [:-] for stronger shoots is to change the shooting unit for a marui or vstank unit ( ~ x2).

>>>tanker ,
could you post pics that shows where the wires goes
on the motor of the shooting unit ?
(hard to find).

swathdiver

Those holes increasing power are a myth. Chrony testing doesn't support the theory. I use 6.04mm airsoft barrels without extra holes and increase 30fps on average depending on the gun. You can swap out the guts of a VS unit and go from about 80fps for a stock HL to about 140 with the VS. Add the brass barrel and heavier spring and you get about 190. One member gets over 220 consistantly.

martin g

mmm, I can only offer my proffessional knowledge, and the suction theory doesnt really add up in ballistics theory, air, gas or otherwise. If the BB was a very tight fit I could see some mileage in it but for me relieving the pressure halfway down the barrel would reduce velocity. I am happy to be put right of course. Remember on automatic weapons the gas is vented back to actuate the reloading mechanism so it has to be a positive pressure, suction is negative pressure i this case. I will need to actually look up how an air soft gun operates to be sure, so perhaps I should before shouting off of course it is possible that both occur and the BB doesnt get out of the barrel in tme before the vacuum occurs. That confused it didnt it!!

tanktrack

hope these help shutz if not let me know exactly what you are after...
and yes that last post left me scratching my head martin

tanktrack

sorry forgot to add the piccies (told you i was confused martin )

scradge

is the hole not for the hop op system! thats similar to my bb gun! the hole usually has a small rubber ball in to put backspin on the ball making it go father!

Wozwasnt

I covered up the hole in my barrel with a bit of electrical tape and it stopped working. The bb pellet stopped half way down the barrel. Took the tape off and it worked fine, put the tape back on again and it stopped working.

tanktrack

Shall have to try that Woz ... !! Shultz hope these pics are a little more helpfull ...

martin g

Ok, did a little research. It seems there is a little truth in all comments just to complicate matters. The airsoft gun operates in a slightly differnet way than I assumed tut tut. As mentioned, In the common ( small arm) type airsoft gun there is a 'diaphram' device that puts a reverse spin on the BB and also links to the hop up system, so it could be to do with that, was there a rubber element to it??. Increasing power is usually done by uprating the spring and piston (bolt to some). There is no metnion of whether the hole reduces pressure or vacuum so thats still a slight mystery. We have comments above of non drilled barrels improving velocity, AND blocked holes reducing it! so thats also up for anyome to try out, would be interesting to find out of course.

Basically for any who wish to know, the motor cocks the weapon with a geared system by compressing the spring, then a round is fed into the breech, the spring is realeased, the piston pushes air through a nozzle which compresses it and that shot of compressed air shoves the BB down the barrel.

tanktrack

cheers martin and there was no rubber element to be seen... when i have completed the modifications
i shall try the above mentioned taped up mod and see what happens...

tanktrack

Ok couldn't wait have just tried the gun ... with hole blocked bb stopped half
way as stated above... open hole it shoots fine [&o] one thing i did notice was air escaping down
the side of the barrel where it slots into airsoft unit... when i re assemble shall try to
remedy this with some kind of seal

Wozwasnt

I glued my barrel to the airsoft gun give a better seal.

martin g

Ok, starting to make sense now, BB's must be a snug fit then, tends to add up that way.
Anyone know if uprated springs are available then?

Captainbertie

Hi,

I machined a solid barrel from Aluminium for use on my T34 with a 6.040mm bore and no air hole along it...it shoots great..........very high velocity too so I'm stumped........

CaptB

scradge

upgrade springs can be baught for airsoft guns but you have to be carefull! too powerfull a spring and Whoops ive just shredded my gears!

annother alternative would be to use a Gas bb system (i have a gas desert eagle its REALLY powerfull!) the advantages are that instead of air cylender you have a valve but you need to make space for a gas tank (in a gun its in the magasine)

alot of gas bb guns have a blow back system.... hmmm i small i idea for recoil just appeared

Wozwasnt

I may have to fit one of these to the Jagdpanther I'm planning (no turret and lots of room for a gas cylinder).

swathdiver

Heng Long airsoft units do not have hopup. The rubber bushing inside the breech is there simply to hold and guide the bb down the barrel when the piston fires. VS airsoft units do have the hopup feature.

schutzstaffel

it was about time you apear here swathdiver[sm=wink_smile.gif]

i was overhead here [sm=drowning.gif]



the h.l. barrel hole ,is it still a mistery?