Mp7 upgrades,,,,,,,,fps?

[greg]

Is the mp7 worth upgrading?

 

I'm thinking of throwing the lalax stuff at one, but wonder if it's worth the time & money?

 

Has anyone out there done it? If so what fps do ya now get? Specifically the lalax spring or deepfire 80ms.

 

Please don't bother with the 'in theory' tosh 'cos I can work that out for myself. What I need is first hand info if you have actually done it. Any practical advice is also welcome.

 

 

Greg.

[tome]

Try seaching "mp7a1"

 

I put a bearing spring guide and standard length inner barrel in and get 260fps.

[Kousnik]

mount an external 8.4 and itll kick out abour 265.

[Phatvortex]

Thread hijack

 

Does anyone know of a takedown guide for the MP7?

 

The cocking handle spring broke off and is floating around inside :/

[Docv400]

mount an external 8.4 and it'll kick out about 265.

Increasing voltage doesn't increase fps, only ROF.

I fitted a 6.03 tightbore to mine and it went up to 260ish fps from 240.

I use 0.25s and the range is pretty good.

I run an external 7.2V 3000mAh pack and the rof is great, approx 17/sec.

I wouldn't go to an 8.4, I don't think it would last too long....the gun that is, not the battery!

[greg]

Thank you for replys.

 

Yes, I too would like to know how a battery increases fps????? But hey, I'll try any thing once!

 

So, anyone out there done a spring change??

 

 

Greg.

[Carbine]

I had a KM 6,04mm barrel, bearing spring guide, ball bearing bushings and a 9-Ball piston head in mine. I was getting around 70m/s with 0,2g BBs.

 

I really think the best upgrades for the MP7 are the tightbore barrel and ball bearing bushings. The bearings increased ROF considerably and made the battery last quite a bit longer.

[Rusty65]

Thank you for replys.

 

Yes, I too would like to know how a battery increases fps?????  But hey, I'll try any thing once!

 

So, anyone out there done a spring change??

Greg.

<{POST_SNAPBACK}>

A larger battery usually has a lower internal resistance.

 

If the MP7 draws the same current in full auto then the battery with the lower internal resistance will be able to supply a larger voltage than the battery with higher internal resistance.

 

Example

Say the stock battery has an internal resistance of 0.2 Ohms and the MP7 draws 5amps on full auto. The voltage drop due to the battery's internal resistance will be V=IR (Where V=voltage I=current and R=resistance)

 

Therefore the voltage drop across the battery is:

 

5 Amps x 0.2 Ohms = 1 Volt

 

This means the gun is effectively running off of 6.2 volts (7.2 volt stock battery)

 

 

Say we drop the internal resistance in half then the voltage drop is then:

 

5 Amps x 0.1 Ohms = 0.5 Volts

 

This means the gun is then running off of 6.7 volts.

 

 

Now given that power in watts can be worked out by using the following formula:

 

Power (Watts) = Volts (Volts) x Current (Amps)

 

Then we can therefore see that the battery with lower internal resistance offers more power to the gun. More power = the motor turning quicker giving a higher rate of fire.

 

 

Hope this is helpful.

 

Rusty65

[crablegs]

A larger battery usually has a lower internal resistance.

 

If the MP7 draws the same current in full auto then the battery with the lower internal resistance will be able to supply a larger voltage than the battery with higher internal resistance.

 

Example

Say the stock battery has an internal resistance of 0.2 Ohms and the MP7 draws 5amps on full auto. The voltage drop due to the battery's internal resistance will be V=IR (Where V=voltage I=current and R=resistance)

 

Therefore the voltage drop across the battery is:

 

5 Amps x 0.2 Ohms = 1 Volt

 

This means the gun is effectively running off of 6.2 volts (7.2 volt stock battery)

Say we drop the internal resistance in half then the voltage drop is then:

 

5 Amps x 0.1 Ohms = 0.5 Volts

 

This means the gun is then running off of 6.7 volts.

Now given that power in watts can be worked out by using the following formula:

 

Power (Watts) = Volts (Volts) x Current (Amps)

 

Then we can therefore see that the battery with lower internal resistance offers more power to the gun. More power = the motor turning quicker giving a higher rate of fire.

Hope this is helpful.

 

Rusty65

<{POST_SNAPBACK}>

Yes that is all great, but he asked FPS not rof, but there is no way to give a gun more fps by a battery alone.

[Rusty65]

Whoops, I guess working night shifts seriously degrades my reading skills.

[Docv400]

I work nights, and I read it OK

I had a thought a while ago, that if you had a gun with a relatively heavy piston and a high ROF, the piston might possibly travel a little past the normal 'release' point (i.e. further rearwards) due to it's momentum, thus compressing the spring slightly more and getting a slight increase in fps...just a thought

[Rusty65]

That is an interesting point (the piston momentum idea, not the lack of my reading skills ).

 

I assume that the spring has enough play in it to be compressed a little more then the gears would allow. However I'm not sure if such a light part such as the piston assembly would have enough momentum to increase the FPS by a noticable amount. At least not with the stock motor or without increasing the wear on the gears/bushings.

 

Perhaps it could be the o-ring in the piston expanding due to friction caused by the increased ROF and increasing the pneumatic efficiency of the gearbox?

[nasty-nate]

alright, i posted in another thread, and i might as well post here--

 

heres my package--

http://neasg.org/ppost/showphoto.php/photo/312/cat/509

 

everything together totaled to over 600 bucks, although its being traded now for a fully loaded glock, plus cash to buy a tm m14 soc, anyways back to here-- just watch out when you upgrade the box, i had everything put in, then thought i stripped a piston, when all it was was the piston jumped off the track, and needed to be re-adjusted, and add some locktite to the screws so they arent so loose...

 

 

i love/loved mine, it was just time for new things....

[NeoVeNoM]

My MP7 is upgraded and shot a whooping 280 fps unfortunately the tappet plate broke.

And there is no company that makes reinforced tappet plates.

That said I haven't shot with it for more than 8 months.

 

More companies should bring out after market stuff for this replica.

[stewpidbear]

Did the full Laylax upgrade, including a new air seal chamber(hop), with a 6.03 barrel and ended up with an fps of just under 300fps. The full upgrade is quite expensive so you have to decide if it is worth it, but with it, you can use it as a field weapon not just a cqb one. I run it with an 8.4 battery in a small box fixed to the ris rail.

[greg]

Nasty,

 

Where'd you get the gears? & were they really necessary?

 

 

Stew,

 

When ya say 'full' d'ya mean piston/cyl head, cylinder, spring, spring guide, 215x6.03mm barrel & bearings, or is there more??

 

 

Greg.

[stewpidbear]

Nasty,

 

Where'd you get the gears?  & were they really necessary?

Stew,

 

When ya say 'full' d'ya mean piston/cyl head, cylinder, spring, spring guide, 215x6.03mm barrel & bearings, or is there more??

Greg.

<{POST_SNAPBACK}>

 

Yep, eveything, apart from the gears. Best guide, although you have to buy it, is the Airsoft Press one, that also comes with other small bits and pieces.

 

http://www.airsoftpress.com/tune_up_kits.htm

 

check out the link.

 

Also forgot this Nine Ball External Battery Adapter, very useful!

[greg]

Nice one, many thanx,

 

 

Greg.

[Pendra]

My TM MP7 shoot at around 280 FPS last time I chronoed it. Used a longer 6.03 inner barrel and the NineBalls updrage spring. The ball bearing spring guide would also increase the FPS but I didn't want to go for external battery attachment. With that setup my ROF ok and I can fire 300-400 BBs before my battery goes dry. With 2 batteries I can use the gun all day.

[PECEMKR45]

I am hoping with all the ACM AEP'S , that we will see more upgrade support , hopefully better prices.

[Stealthbomber]

My well MP7 is already shooting at 265fps. That's exactly the same as my TM P90 was!

 

However, the hop-up was awful, as in almost non-existant.

I started to take the gun to bits to replace the hop-up, took the top rail off and looked inside, realised how far down the barrel was and gave up almost immediately.

 

All the guys, above, who have actually bothered to upgrade an MP7 have my utmost respect.

Far too fiddly for me to attempt.

[Pendra]

I bought a TM because I didn't want the internals to fail. Next day I spent 5 hours to fix the missfeed and the max 10m range. The complex tappet plate/nozzle problem was fixed with very carefull dermeling and cutting. TM my ***.