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-   -   Is it possible? 550FPS+? On a KJW M700... (https://airsoftcanada.com/showthread.php?t=24737)

KraziAzn June 2nd, 2006 11:45

Is it possible? 550FPS+? On a KJW M700...
 
I was looking around ebay... and well...here it is
M700

is possible? 550fps-600fps on green gas....

Droc June 2nd, 2006 11:49

or higher
word has it, propane(green gas) has pushed out of the box KJW M700 upto 900fps on hot days, but usually settles down to around 600fps...so I hear.

KraziAzn June 2nd, 2006 11:51

holy hell...900fps? damn... =O

BloodSport June 2nd, 2006 11:58

yea seen one shooting around 700, left a scar on my team captains leg. He then used it to leave one on the original shooters ass cheek.

Greylocks June 2nd, 2006 12:16

I have an idea, let's start playing this game with .22LR!
The legalities will be far simpler, and there will be no more bullshit about ignoring the hits.

Go for it, newbies, please.

Maybe Darwin will finally do for us what common sense cant manage.

TFZ-OZ June 2nd, 2006 13:22

easy to make that comment Grey when ya don't play... 22 eh?

He never made ref. to playing with it - just asked a simple question grey.... trigger happy agian i see...

900 settled down to 600 is still insane...lol

Droc June 2nd, 2006 13:49

the problem is easily fixed. there is a screw that can bring it down to acceptable field limits. Its still one of the guns thats better off using Duster.

cheaper in the long run, since you can run it from 300fps to +600fps, its usable in low fps countries like the UK and insane fps areas like hong kong.

I belive it ships with a tightbore also. And considering its price, Id say its a deal.

Carvs June 2nd, 2006 14:02

Quote:

Originally Posted by Droc
I belive it ships with a tightbore also. And considering its price, Id say its a deal.

In my talks with CDN Stalker it does. 6.05 I beleive. I am in talks with Grim to get one but his next KJ order isnt till Augest/September :(. But considering it being only 310 from Grim, its a bargan.

Neverhood June 2nd, 2006 14:03

A guy at the MAA's recent Noob Day had a M700 and when he went to chrono in he was more than alittle surprised when the readout said 575. Luckily there were a few gun techs onsite to help him with that. :lol:

ToRN June 2nd, 2006 14:15

I used to own a Tanaka M40a1 (essentially the same thing, KJW copied it almost exactly from the Tanaka M700)

Believe me, the high FPS is very possible. At the first game I ever attended with it, I chronied it with the adjustment wide open, just for S&G. twas at 750fps with .36s on the first shot, and about 700 with the second.

Freedom Fighter June 2nd, 2006 16:07

Quote:

Originally Posted by wolfpack--oz
easy to make that comment Grey when ya don't play... 22 eh?

He never made ref. to playing with it - just asked a simple question grey.... trigger happy agian i see...

Greylocks is like the quiet guy who just "shows up" to house parties. No one claims to actually know him or who might have invited him, but he's always permitted to stay because once he gets drunk it is enjoyable for people to sit and watch him swearing and throwing punches at his shadow.

Those people are great to have around.

Greylocks June 2nd, 2006 16:08

Good jab FF.
Now I can go enjoy a beer.

CDN_Stalker June 2nd, 2006 16:19

Quote:

Originally Posted by Carvs
Quote:

Originally Posted by Droc
I belive it ships with a tightbore also. And considering its price, Id say its a deal.

In my talks with CDN Stalker it does. 6.05 I beleive. I am in talks with Grim to get one but his next KJ order isnt till Augest/September :(. But considering it being only 310 from Grim, its a bargan.

It does, has been measured.

Mine, on the hottest day last year, was like +36C and humidex of +43ish, I chronied, WITH 0.20g BBs (my point to dispell 700+fps with 0.36g BBs), shot 710 on propane first shot, second was 680fps, third was 590fps, the remaining 20 shots were between 550-560fps. Is why I only use propane under +25C, and duster over +25C (duster on same day first couple shots were 460-470, all the rest for 20 rounds settled down to 440-450fps) and use my usual "minimum 100ft, but with descretion" engagement distance.

Best way to use it, fill your mag and load it in empty. Cycle & fire the gun 4x, then load BBs in and go play. That way the pressure settles down and it's a hell of a lot more consistant for 20 shots (two full mags.) And the gun performs best with a clean barrel, every 20-30 rounds if you can. Over the course of two days, I had 4 strict cycles on 4 targets, dry patch through the barrel, fill the mag with propane, dry fire 4x, load the 10 BBs (don't even think about 0.20g, 0.25g are fine within 100ft but suck otherwise), fire them off one every 10 secs. Every target had a dime sized group at point of aim. Every time. When shots start to veer off, barrel needs cleaning.

linkster June 2nd, 2006 17:27

i thought that in canada your "replica firearm" cant be over 500 FPS! over that and its conciderd a pelit gun......i think......

CDN_Stalker June 2nd, 2006 17:59

Grey area. For it to be considered a "firearm", must meet both requirements, over 500fps AND 5.7 joules muzzle energy (0.20g BBs at +740fps). For pellet guns, they use heavier ammo and are based upon fps due to the common wieghts of pellets/steel BBs, and require an FAC/PAL to buy one. Since airsoft ammo is lighter, they fall inot a general grey area that is hard to explain. Doesn't matter really, many have protested and equal amounts have failed becuase of such a grey area. All I can say is to use common sense, either increase your minimum engagement distances or drop the gas power down. Gonna get in shit if one doesn't obey common sense, so that should keep the ratio between performance and zero complaints reasonable.

Gryphon June 2nd, 2006 19:48

Yep. According to the regulations and Arnie's FPS/Joule calculator, we can push 785 fps with a 0.20g before it becomes a firearm.

Kid June 2nd, 2006 20:00

Totally off topic, but I don't want to gravedig and the info has been given, may as well.

CND_Stalker,
You've mentioned that you have mags with 30 rnds?
Which is that? Would that happen to be the long Tanaka mags?

There were conflicting reports on that, so I was wondering about that.

Or would that be the custom one MadMax was working on...?


You had mentioned before that you had planned to do some modifications in another thread. Have you had any more progress on those? Any recommendations for the ASC comunity?

Mantelope June 3rd, 2006 00:33

Quote:

Originally Posted by CDN_Stalker
I chronied, WITH 0.20g BBs (my point to dispell 700+fps with 0.36g BBs

Guns don't usually translate perfectly between different BB weights even if you're using the proper math. This is especially true with gas guns; a heavier BB means it will be in the barrel for a longer period of time, which means it will be accelerated for a longer period of time. This is why you get such good performance with heavy BBs in your Glock.

MadMax June 3rd, 2006 01:49

Definitely a salient point with gas guns. It appears that AEGs and other spring guns are pretty much constant energy guns in that the muzzle energy is consistent dispite changing pellet weight. However, many gas guns do not exhibit constant energy with different bb mass.

I suspect that when lighter pellets are used, the breech pressure drops because the pellet accelerates down the barrel fast. The rapid expansion of volume behind the pellet results in higher pressure drops in restrictions like in the fire valve or other gas flow paths which causes lower breech pressure.

Reduced breech pressure means less force acting on the pellet (pressure x area) which means less work done accelerating the pellet (reduced force x distance).

This doesn't appear to be the case with AEGs which have very simple gas flow paths. The bore of the nozzle and cylinder centre port is not much smaller than the barrel. The reaction force of accelerating the pellet appears to be the dominant restriction.

Gas guns have more convoluted flow paths and the fire valve takes a little time to fully open. A heavier pellet presents a more significant flow restriction than a lighter one (relative to the flow resistances) so it can absorb more work energy.

In essence, I am conjecturing that an ASG can be approximated as a series of gas flow resistances analogous to electrical resistors in a circuit.

The flow restrictions of various orifaces and the barrel represent a chain of smallish resistances which are constant. They will incur a higher pressure drop at higher flow rates. Similarly a resistor incurs a higher voltage drop at higher currents (Ohms law: V=IR)

However, the pellet represents a wierd resistance. It's resistance varies with time. The pressure drop across a pellet (between breech side and front side) is the difference in breech pressure and atmospheric pressure. The odd thing is the resultant flow rate is dependant on how fast the pellet is moving. A faster pellet ends up having a higher rate of volume change behind the pellet. In a sense, the pellet starts out at a high flow resistance which decays to a lower flow resistance by the time it's screaming out the barrel.

If the constant resistance of the flow path upstream of the pellet is very small, nearly all of the pressure drop occurs across the pellet so different weight pellets will have the same work done on them for the same fixed barrel length ~ constant muzzle energy despite different pellet weights.

If the constant resistance of the upstream flow path is not negligible, then the pressure drop across the various resistances in the flow path will reduce the pressure acting on the pellet so lighter pellets have less work done on them and therefore have higher speed (higher flow rate), but less muzzle energy because the average force acting over the barrel length is less.

Now I have to put my head back together because my brain just exploded.

MadMax June 3rd, 2006 01:54

In response to the original post, it is quite possible that a KJW M700 on ebay pushes well over 500fps w' 0.2g pellets:

http://www.airsoftcanada.com/showthread.php?t=14509

KraziAzn June 3rd, 2006 14:04

Thank You. Wow that was one hell of a thread. =D

CDN_Stalker June 3rd, 2006 16:42

Quote:

Originally Posted by Kid
Totally off topic, but I don't want to gravedig and the info has been given, may as well.

CND_Stalker,
You've mentioned that you have mags with 30 rnds?
Which is that? Would that happen to be the long Tanaka mags?

There were conflicting reports on that, so I was wondering about that.

Or would that be the custom one MadMax was working on...?


You had mentioned before that you had planned to do some modifications in another thread. Have you had any more progress on those? Any recommendations for the ASC comunity?

I only own 10rd standard mags in my M700, although a Tanaka 30rd mag would be a neat change to make.

Only mods I did and mentioend on my M700 were down withint a couple days of receiving it, cut the striker spring down by two coils to reduce the amount of force it releases gas at, making it release gas more consistant; and remove the stock to barrel support to let the outer (and result inner) barrels lie as they want to. Truns out the three I ordered (two are in the hands of team mates, same thing with theirs) is the outer barrel wants to lie to the left a bit, meaning when we received them, the inner barrels were slightly curved due to the support. Used to get 10shot CD sized groups at 30ft the first few weeks I had it, things worked in well and now I get consistant dime sized groups with it at 30ft with whatever ammo I use (Straights are not as good though unless washed). Only thing I did mod was to install a G&G Striker Spring for the Tanaka M24 and M700, found I didn't like it (have to NIB ones for sale though) as it made the power go up even MORE from stock, increased bolt pull and trigger pull as well.

One thing I found is tha the KJW M700 needs to have a dry swab run through it every 30 or so shots to keep the consistancy at it's best, otherwise flyers start occuring.


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