22 replies to this topic

[Static]

Hi Guys,

I've recently purchased the KWA MP7 with 3 extra magazines, so all brand new.  After gassing up all the mags and testing the gun, I've noticed that on full auto, the first second of each burst has a very high rate of fire, but then drops to a mediocre rate.  It does this with all 4 magazines, each completely filled with green gas.  Is this normal or is there something I can do to keep the higher ROF?

[akiraspeedstar]

I'd imagine it has something to do with the gas/gun/magazine cooling down which would lower the fps and rof.

[Static]

I'm not getting anywhere close to the stated 20 RPS.  After the first second of firing it's a dramatic decrease in ROF, it has nothing to do with temperature.

Edited by Static, 19 April 2012 - 12:09 PM.

[greatwatermelon]

Is it possible you can upload a quick video of it?

[Static]

I can get one up tomorrow sure.  It's night time so I can't take it out and I don't like dry firing.

Edited by Static, 19 April 2012 - 12:18 PM.

[Outlaw1995]

Perhaps its your can of green gas. It may not have the pressure needed to keep the cyclic rate up. Try buying a new can of GG and try again.

[greatwatermelon]

That's a possibility.

[R_King91303]

Hmmm... is it a self correcting problem? I.e. if you do burst fire but wait a few seconds between bursts do you notice a decrease in ROF?


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[Outlaw1995]

R_King91303, on 19 April 2012 - 03:26 PM, said:

Hmmm... is it a self correcting problem? I.e. if you do burst fire but wait a few seconds between bursts do you notice a decrease in ROF?


Posted from my iPhone

Could be, but that is rarely an issue to see a decrease in ROF between bursts unless you are running out of pressure/ gas in your magazine. With a full mag, on a sunny warm day, you shouldn't be experiencing these issues.

[R_King91303]

Outlaw1995, on 19 April 2012 - 04:48 PM, said:

Could be, but that is rarely an issue to see a decrease in ROF between bursts unless you are running out of pressure/ gas in your magazine. With a full mag, on a sunny warm day, you shouldn't be experiencing these issues.

I asked if its self correcting because something within the gas delivery system (the bolt) could be frosting over to cause the decrease in ROF? More precisely I'm thinking if it could be part #23 needing to be re-lubed if it is a simple case of frosting?


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[Outlaw1995]

When a GBB is fired, green gas is rushed from the mag, to the nozzle, to thrust the bb outward. When this happens, the mag gets cold, (not the bolt) and the less gas in the mag, the less pressure. It should make sense that on full auto, the pressure is eventually lost, and your ROF drops really low. But the NS2/ FV gas systems have helped conserve gas pressure to keep the ROF the same. My guess is that the pressure in your gas can is low. If a new can doesn't work, then we could go from there. Have you maintained your MP7 well?

[Static]

Outlaw1995, on 19 April 2012 - 02:10 PM, said:

Perhaps its your can of green gas. It may not have the pressure needed to keep the cyclic rate up. Try buying a new can of GG and try again.

This is something I thought of, I have a different can of gas and I will be trying them both out when I finish work and let you know the results.

R_King91303, on 19 April 2012 - 03:26 PM, said:

Hmmm... is it a self correcting problem? I.e. if you do burst fire but wait a few seconds between bursts do you notice a decrease in ROF?

No it's not self correcting, the higher ROF doesn't remain regardless.

Outlaw1995, on 19 April 2012 - 05:19 PM, said:

When a GBB is fired, green gas is rushed from the mag, to the nozzle, to thrust the bb outward. When this happens, the mag gets cold, (not the bolt) and the less gas in the mag, the less pressure. It should make sense that on full auto, the pressure is eventually lost, and your ROF drops really low. But the NS2/ FV gas systems have helped conserve gas pressure to keep the ROF the same. My guess is that the pressure in your gas can is low. If a new can doesn't work, then we could go from there. Have you maintained your MP7 well?

Yes, as I said, the MP7 and the mags are all brand new, I haven't even fielded it yet.  The only thing I've done is cleaned the barrel after opening because there was some grease in it (soap and water, no silicon).

Edited by Static, 20 April 2012 - 02:23 AM.

[Outlaw1995]

Have you noticed anything else besides the drop in ROF? Have you looked into the bolt while firing to see if there's anything else going wrong?

Besides that, I think the main culprit is your green gas can and how it may not have enough pressure.

Try uploading a video if you can. I'm very curious to see the problem.

[Static]

Not that I can see no, but I'll check a little more intently with what the bolt is doing while cycling.  As soon as I get back from work, I'll gas it up with 2 different types of green gas and film it.

[Outlaw1995]

Static, on 20 April 2012 - 05:37 AM, said:

Not that I can see no, but I'll check a little more intently with what the bolt is doing while cycling.  As soon as I get back from work, I'll gas it up with 2 different types of green gas and film it.

Thanks man! Now get back to work. Lol jk

[Static]

OK this looks to be solved, the newer gas I bought doesn't suffer from the same issue as I stated above.  I've also just discovered the gas I was using is some kind of bio alternative that can actually lower your FPS, so yeah.  Thanks for comments as always chaps, very helpful.

[R_King91303]

Static, on 20 April 2012 - 11:13 AM, said:

OK this looks to be solved, the newer gas I bought doesn't suffer from the same issue as I stated above.  I've also just discovered the gas I was using is some kind of bio alternative that can actually lower your FPS, so yeah.  Thanks for comments as always chaps, very helpful.

What brand of GG were you originally using so we know to avoid it?


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[Static]

Abbey 144a.

By the way, is there a break-in period with the MP7?

[gcw360]

Static, on 21 April 2012 - 05:21 AM, said:

Abbey 144a.

By the way, is there a break-in period with the MP7?

No break in for GBBs.  At least not the current line. Break-in really applies to the AEGs for two reasons, grease in the gearbox being shot out and the inner barrel getting better with time.  While your MP7 barrel should improve over time due to the fact it is a brass barrel, I wouldn't say you have any real breaking period.  The performance is very good right from day one.

[Outlaw1995]

Static, on 21 April 2012 - 05:21 AM, said:

Abbey 144a.

By the way, is there a break-in period with the MP7?

Never heard of this gas. I'll look into it...