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Thread: .117 BB Ballistics
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April 9th, 2007, 01:25 PM #1
.117 BB Ballistics
I'm extremely curious of what the ballistics are of small 177.cal BBs at ranges of 30ft+ when fired at high velocities.
Has anyone ever use a BB for such a distance, and is there a lot of drop off?
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April 9th, 2007, 04:46 PM #2
Re: .117 BB Ballistics
what do you consider to be high velocity and what do you consider to be a lot of drop of? at 30ft, it shouldn't be too bad. the higher the velocity, the less drop it will have.
since a BB gun barrel is smooth bore, depending on how much spin and in what direction it spins, the BB can curve this way or that. if it curves up or down, that throws off your trajectory calculations.
vincewww.bloomautomatic.com - Golf Ball Launchers for AR-15, SKS, FAL, and many others
www.bloomautomatic.com/lbsc - Long Branch Sportsman's Club, Long Branch, PA
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April 9th, 2007, 08:55 PM #3
Re: .117 BB Ballistics
My BB guns were rifled......and threw at about 900fps. A rifled barrel will stabilize round ball.....just ask the muzzleloader crowd. You just have to get the twist right.
Weigh a BB in grains and I can plug it into the ballistics calc (I don't have one on hand). We'll need the ballistic coefficient as well.
I taught Chuck Norris to bump-fire.
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April 9th, 2007, 10:09 PM #4
Re: .117 BB Ballistics
what kind of BB gun did you have that had a rifled barrel? seems that a steel BB wouldn't engrave on the rifling like a lead pellet would.
Vincewww.bloomautomatic.com - Golf Ball Launchers for AR-15, SKS, FAL, and many others
www.bloomautomatic.com/lbsc - Long Branch Sportsman's Club, Long Branch, PA
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April 9th, 2007, 11:07 PM #5
Re: .117 BB Ballistics
Well I hear rifling does little for round rounds, however rounds that can mold to the rifling is proven to be another story.
I just have a daisy btw, and I can pump it way up to over 2000 FPS, but lets just say at 30 ft 750 FPS. What kind of drop off would there be then?
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April 10th, 2007, 01:19 AM #6
Re: .117 BB Ballistics
The first one was a simple Daisy 880. The ball only has to flow along the track of the riflings, not mold to it. The riflings did cut into the pellets, though. You need very little twist to stabilize a round ball. 1 turn in 70 inches in some muzzleloaders with heavy ball.
OK, I'm intrigued with this..... I'll play.
Check this out:
http://www.airgunexpo.com/airgundb/pelletbc.cfm
The Daisy BB has a BC of .009. (wow, that sucks).
The Copperhead BB weighs in about 5.1 grains.
At a Starting velocity of 700fps....
At 5 yards: 652.9fps -.09 drop
10 yards: 609.3fps -.39 drop
15 yards:568.6fps -.92 drop
20 yards: 530.3fps -1.72 drop
25 yards: 494.3 fps -2.83 drop
30 yards 460.4 fps -4.3 drop
I taught Chuck Norris to bump-fire.
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April 10th, 2007, 06:04 AM #7
Re: .117 BB Ballistics
www.bloomautomatic.com - Golf Ball Launchers for AR-15, SKS, FAL, and many others
www.bloomautomatic.com/lbsc - Long Branch Sportsman's Club, Long Branch, PA
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April 10th, 2007, 08:21 AM #8
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April 10th, 2007, 09:28 AM #9
Re: .117 BB Ballistics
Most of the really powerful ones are spring piston guns, not pump-up pneumatics. also some precharged guns, like the airforce guns will exceed 1000fps.
i fired a winchester spring piston pellet rifle and it went supersonic. i volunteered on the indoor range at the NRA convention in pittsburgh. during setup, we had to sight the guns in, etc. took it out of the box and CRACK went the sound barrier. they put it away. little too loud for indoor use. since it was new it could have had some oil left in it and dieseled.
seems like most of the newer pump guns will only let you get so much pressure before the bleed off. like more than 10 pumps and you can feel it's not really pumping any more.
vincewww.bloomautomatic.com - Golf Ball Launchers for AR-15, SKS, FAL, and many others
www.bloomautomatic.com/lbsc - Long Branch Sportsman's Club, Long Branch, PA
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April 11th, 2007, 12:30 AM #10
Re: .117 BB Ballistics
75 PSI a pump, and 30 pumps later mathematically = 2250 fps Mr friend told me he tried it for 100 one time. I'll never even think about it.
So I'm looking at about 4inch drop. That's good to know just for starters. I'm buying a cheap scope, and after I get it put on I'll be doing some target practice at 30 ft.
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