The Military/Police's BBMG

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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jackssmirkingrevenge
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Mon Oct 13, 2008 12:02 am

The basic design is the same, what gives the high ROF and power potential is the availability of high pressure. Double the pressure and you'll double the power, it's that simple, so if you build a strafer that can handle say 500-1000 psi, you have a veritable ripsaw that will cut through pretty much anything at close range.

Personally I would love to see a strafer that can handle unregulated 4,500 psi air directly from a SCUBA tank, that would truly be worthy of being placed in a photo comparison with power-burning submachineguns :D

The idea is similar in concept to the American 180 submachiengun that fired the 22LR rimfire round - a relatively low powered cartridge, but fired at such a high rate of fire that it was a viable weapon for law enforcement use.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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ISA_Yoshi
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Mon Oct 13, 2008 10:21 am

4500 psi? Would even metal (plumbing) pipes be able to handle that without leaking? (if not worse)
I'd hate to be on the receiving end of that.

Also, I'm not sure exactly on the model, but I think it's the M249 that gets about 900 rounds per minute. When compared to the Dillon Aero M134 which gets 3000 rounds per minute, the difference in accuracy (hit ratio) isn't just 3 times that of the M249, but over 10 times. Higher rate of fire definitely greatly improves chance of a hit. I can't remember right now why I needed to say this, but it had some relevance.
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VH_man
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Mon Oct 13, 2008 10:42 am

those 4500 PSI tanks are actually regulated down to 1000 PSI on the output port, or lower in some cases. you can put normal plumbing parts right on the end of that thing.

And if you didnt notice, the muzzle velocity is about 600 FPS..... meaning it cant be running on more than 200 PSI.........
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Ragnarok
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Mon Oct 13, 2008 10:47 am

ISA_Yoshi wrote:the difference in accuracy (hit ratio) isn't just 3 times that of the M249, but over 10 times. Higher rate of fire definitely greatly improves chance of a hit.
I'd be surprised if the accuracy improved at all. The number of hits per minute will increase, but an increase of 10 times when the ROF has only tripled sounds of dubious reliability to me.
Does that thing kinda look like a big cat to you?
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ISA_Yoshi
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Mon Oct 13, 2008 11:02 am

The strafer I fired was set to 170 PSI for 600 fps with .2g bb.

As for ROF to hit ratio, I'm sure on that point. Accuracy might have been a bad word choice in that case.
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Ragnarok
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Mon Oct 13, 2008 11:09 am

ISA_Yoshi wrote:As for ROF to hit ratio, I'm sure on that point. Accuracy might have been a bad word choice in that case.
Why exactly should you, by throwing three times as much ammo, hit 10 times as often?
That would also have to imply each individual round had three times the likelihood of hitting!
Does that thing kinda look like a big cat to you?
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ISA_Yoshi
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Mon Oct 13, 2008 11:19 am

I'm sorry. it was the M240. I saw this video on the news originally.

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jackssmirkingrevenge
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Mon Oct 13, 2008 11:33 am

The point is that it's not more accurate, it just has a higher shot density per minute, meaning that for a given amount of time, you're obviously going to get more hits because you're throwing more rounds at the target.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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ISA_Yoshi
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Mon Oct 13, 2008 11:43 am

Right. hit ratio (number of hits/time)
My point was the 1:10 instead of 1:3 ratio (M240:M134)
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Ragnarok
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Mon Oct 13, 2008 11:52 am

ISA_Yoshi wrote:My point was the 1:10 instead of 1:3 ratio (M240:M134)
That 1:10 ratio only exists because they're firing 10 times as many rounds - not 3 times as you claimed. The M134, being a minigun, is a type of chaingun, where the rate of fire is controlled by a motor, and is thus variable.

For that test, I would imagine it was turned way up to way past 6000 rpm. In reality, they're normally used at about 3000 rpm to reduce the likelihood of jams.

Fire 10 times as many rounds, you'll get 10 times as many hits. Fire 3 times as many rounds, you'll get 3 times as many hits.
Give the M240 and M134 the same number of rounds, you'll get roughly the same number of hits. That's the way it's got to work.
Does that thing kinda look like a big cat to you?
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ISA_Yoshi
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Mon Oct 13, 2008 12:35 pm

I'm pretty sure it was set at around 3000 rounds per minute, and the M240 is somewhere between 900-1000.
I'm not going to argue though.
That was the purpose of the report: the fact that 3x the rounds=10x the hits.
I don't get audio on the university computers, but it has an explanation somewhere in the vid for the phenomenon.
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Ragnarok
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Mon Oct 13, 2008 12:40 pm

ISA_Yoshi wrote:That was the purpose of the report: the fact that 3x the rounds=10x the hits.
For that to be possible, it would have to mean that each round is over three times more likely to hit, which I am not buying.

The attached text quotes an 8,000 rpm fire rate, which would produce about the 10x improvement over the M240.
3,000 rpm wouldn't produce that increase, the physics simply don't allow it.
Does that thing kinda look like a big cat to you?
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jackssmirkingrevenge
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Mon Oct 13, 2008 4:49 pm

Ragnarok wrote:The attached text quotes an 8,000 rpm fire rate, which would produce about the 10x improvement over the M240.
3,000 rpm wouldn't produce that increase, the physics simply don't allow it.
Unless you consider that the minigun platform, aside from its higher rate of fire is apparently more stable and easier to aim than its gas-operated brethren...
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Ragnarok
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Mon Oct 13, 2008 5:21 pm

Yes, to a small degree perhaps, but I don't see it being responsible for a 3x improvement.
Does that thing kinda look like a big cat to you?
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mrbadexample
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Mon Oct 13, 2008 6:06 pm

jackssmirkingrevenge wrote: Unless you consider that the minigun platform, aside from its higher rate of fire is apparently more stable and easier to aim than its gas-operated brethren...
having more barrels would create a more stable thermal base, a single barrel would tend to melt faster, and the gas/spring combo has a physical limit for cycle times. as a barrel heats/fouls the accuracy will go away.

but this doesn't enter into airsoft guns. why anyone would fire 0.2 gram BBs is beyond me. i prefer .177 lead pellets, one shot, one kill.
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