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could someone please ggdt this for me.

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: watto » Tue Oct 23, 2007 9:32 am

ALIHISGREAT wrote:who was that directed at? i shoot at school, mostly .22 rifles.


Wait are you telling me in America they let kids shoot guns at school??? Or do you just drive down to the local school to shoot things like I do because it has a nice big oval?

Edit: Are you talking to me when you say 'who was that directed at?' If so then it was directed at ammosmoke because he is narrow minded and I don't like him.
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Last edited by watto on Tue Oct 23, 2007 11:06 am, edited 1 time in total.
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Unread postAuthor: ALIHISGREAT » Tue Oct 23, 2007 10:36 am

i live in the uk... i sometimes go to rifle shooting after school and we shoot the gp cadet rifle in ccf (combined cadet force)
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 23, 2007 10:54 am

who was that directed at? i shoot at school, mostly .22 rifles.


If so you should have an idea about ballistics and projectile drop and know that a 2 gram rimfire bullet travelling at over 1,000 feet per second cannot be compared to a BB with a comparatively poor ballistic coefficient travelling at a significantly lower velocity.
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Unread postAuthor: Pete Zaria » Tue Oct 23, 2007 10:55 am

Sorry to be so off-topic, but I thought I'd answer the question....
Some schools in the US have a rifle team, which practices and competes at the local shooting range. My high school in rural Washington had such a program. The guns were not allowed to be kept on campus at any time, and if I recall correctly, it was .22LR rifles only.

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Unread postAuthor: ALIHISGREAT » Tue Oct 23, 2007 11:08 am

the guns are kept on site at my school.


If so you should have an idea about ballistics and projectile drop and know that a 2 gram rimfire bullet travelling at over 1,000 feet per second cannot be compared to a BB with a comparatively poor ballistic coefficient travelling at a significantly lower velocity.

well i will hop-up my bb so there will be less projectile drop...
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Unread postAuthor: watto » Tue Oct 23, 2007 11:19 am

Pete Zaria wrote:Sorry to be so off-topic, but I thought I'd answer the question....
Some schools in the US have a rifle team, which practices and competes at the local shooting range. My high school in rural Washington had such a program. The guns were not allowed to be kept on campus at any time, and if I recall correctly, it was .22LR rifles only.

Peace,
Pete Zaria.


I must say thats quite astounding to me, I'm not saying its bad or anything, I just can't believe they teach that kind of thing in schools, I would love to have done something like that at school. Personally, I along with maybe 95% of Australians have never shot a real gun, maybe due to the firearms laws over here.

I almost fell off my chair a few year back when I heard that people in texas could actually legally carry guns on them, I can't remember where I heard that maybe on 'bowling for columbine' It makes me think that Australians are being denied the right to defend themselfs...
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 23, 2007 11:20 am

well i will hop-up my bb so there will be less projectile drop...


I think you're slightly overestimating the benefits of hop-up. You can't really judge accuracy by airsoft standards, because in airsoft all you need to do is hit a person, that sort of accuracy is not enough for plinking against your average targets like cans and beer bottles, and even if the BB does hit, it would have lost so much velocity getting to the target that the effects (unless you're shooting paper targets) would be minimal. Also, if your hop-up is going to be unadjustable, it will probably make accuracy worse, not better - unless the upwards thrust to the BB is given at 90 degrees to the horizontal and you're not holding the rifle along the same line, the BB is going to veer off sideways in an unpredictable manner.

If I wanted long range accuracy and power, I would focus on finding a 5.5mm internal diameter barrel that can use 0.22 airgun pellets with little modification (to maintain consistency) and use as long a barrel and as high a pressure as I can afford to make sure I get enough velocity to give a reasonably flat trajectory.
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Unread postAuthor: ALIHISGREAT » Tue Oct 23, 2007 11:48 am

i plan on doing you ethod to alter the pellets to fit the 6mm barrel, how much does a .22 pellet weigh? could you please put it through ggdt with the smae setup at 250psi and 300psi. thanks.
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 23, 2007 12:01 pm

You can get 0.22 pellets weighing from 12 to 21 grains, I would recommend you go for the medium weight pellets at 16 grains which is almost exactly one gram. The heavier ones will yield higher muzzle energies and lower muzzle velocities but since they are designed to be fired from rifled barrels, the weight won't be properly distributed and they won't fly straight.

With a 1 gram pellet and guestimated values for your valve performance, I got around 650 feet per second at 250 psi (14 ft/lbs) 700 feet per second at 300 psi (16 ft/lbs) - note that since you're in the UK this will qualify as an illegal firearm but I suppose being a member of uksgc you're already aware if the 12 ft/lbs legal limit malarkey.

At that power setting, air rifles are usually fired at about 50 yards maximum as being the most realistic range where you can reliably hit a 1" circle.

edit: hint - with a 100cm barrel you get 750 feet per second and 19 ft/lbs ;)
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Unread postAuthor: ALIHISGREAT » Tue Oct 23, 2007 12:07 pm

yeah i already figured it would be too powerful when i was mucking about on that fps/power/range calculator on arnies airsoft. hmm if i hit a 1" circle at 50 yards with an .22 pellet i will be very happy :) and if i can hit a person sized target (not a person though) with a .43g bb at ~100 yards i will be super happy :D but it all depends on the quality of my barrel etc. but it all looks pretty good.
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 23, 2007 12:19 pm

i can hit a person sized target (not a person though) with a .43g bb at ~100 yards


With my 1,200 GBP air rifle setup I can hit an A4 paper at 120 yards ;)

You will probably need to aim several feet above someone's head at that range but on a windless day and if you know how much to compensate for drop, I'd say it can be done.
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Unread postAuthor: ALIHISGREAT » Tue Oct 23, 2007 12:37 pm

360ft, very impressive! but you spent alot of money doing it tho, i have now made it my sole purpose to hit an a4 bit of paper at 120 yards with my 6mm sniper!
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 23, 2007 12:42 pm

how about this guy then:

[youtube]http://youtube.com/watch?v=I5md7Ke4BsA[/youtube]

218 yards firing 16 grain pellets at just over 900 fps (similar performance to my Daystate)

:shock:
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Unread postAuthor: Necrosis » Tue Oct 23, 2007 12:45 pm

In fact I have that same airgun with in fact the same pellets.

I can like hit an acorn at 75 meters away with my noob skillz
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 23, 2007 12:52 pm

Necrosis wrote:In fact I have that same airgun with in fact the same pellets.


I used to have a 12 ft/lbs Air Arms S410 (see attachment), beautiful and accurate but a bit low powered for my liking as well as being light and dainty so I sold it. I've shot a 410 ERB, it's a very good bit of kit but too long for my tastes, I prefer my Mk.3 :D
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