2:45am Frustrations can't break 240fps w/upgrades

[CDN_Stalker]

There is no spring in the hop up unit of the TM MP5s. The only spring I recall in a hop up unit is for the Armalite rifles, this is because the hop up unit and inner barrel is free floating (unlike the MP5 which is secured to the body, which is why MP5s are more accurate than any Armalite), and the spring presses the hop up unit back into the mechbox for proper placement.

Check your hop up unit for any cracks, I had a low fps and double feeding in my A5 at one point, was due to a crack allowing the inner barrel to shift forward a bit. Also, there is a spacer type thingy at the front of the unit that holds the inner barrel, it has a raised lip on it, make sure it faces backwards, otherwise your inner barrel will be held to far forward for proper airseal with the nozzle.

[Rabbit]

So to me it sounds like this could either be one of 2 places.

The Hop Up

or

The Air Nozzle/Cylinder head

[Amos]

It's not leaking out of your cylinder head... unless for some reason you've got a bore-up cylinder

Does the cylinder head stay in the cylinder (read: not fall out due to gravity) when you put it in there?

It sounds like your nozzle and hop-up aren't interacting properly.

[Rabbit]

The cylinder head actually its pretty tight fitting in the cylinder, does not fall out at all.

Is there something i should look at purchasing for the air nozzle and hop up then?

[Amos]

Prometheus air seal nozzles are awesome... and I'm not too sure what's available for the TM Mp5 in the hop-up area...

[Azathoth]

Did you install your new non-linear spring the correct way? Did you reverse the port on your cylinder?

What is the result of the compression test with the air nozzle on? Do you have the right nozzle for you hopup/gun?

Perform the nozzle to seal hopup test. Take your nozzle out of your box and your hopup unit out of the gun. Dial in a tiny bit of hopup, then manually load a BB in the hopup unit. Insert the air nozzle into the hopup unit and shake it. If you hear rattling then it's your nozzle/hopup sleeve not seating BB or air loss.

[cjboi]

Originally Posted by Amos

... The MASK piston head and cylinder head are the best ones on the market right now... I'm willing to bet you have zero first hand experience with them and are just regurgitating something you heard someone else say.

@Remy:

Sounds like you've got a hop-up/nozzle issue..

Did your techs check compression with the nozzle on?

Edit: Totally sounds like a nozzle compression issue, You're going to want a good air seal nozzle, and you're going to want to use a little bit of silicon grease on the outside of the airway on the cylinder head.

I'm not 100% sure on the TM Mp5 (so many different MP5 versions out there!!) but if it has a free-floating hop-up unit, did you remember to replace the spring that goes in front of the hop?

My friend bought ARS MASK Duo POM for Ver. 2 for his G&G mp5 and it sucks... AGAIN BURNT!!! next time stop assuming. I told him to get a modify cylinder kit and I installed it for him and guess what??? it works like a charm... I'm not a fan of modify parts really, because I had bad experience with them, but I suggested my friend to buy modify cylinder kit because it was a lot cheaper compare to other brands and he didn't wanna spend lots. I have an ICS mp5 sd6 model and the parts are still stock and it still works great (shoots at 346 FPS consistent). I bought a systema bore-up cylinder kit for my gun with Prometheus hard piston and Prometheus m120 spring and it work great, but I kept my gun stock because I use it most of the time for CQB games. I only switch the parts, when I play outdoors.

Your Prometheus Air Seal Chamber Hop-Up Packing (Soft Type) is great, that's what I have for my P90. You have to re-install the hop-up unit on your gun and make sure the bucking is sitting right.

[HKGhost]

I just installed the ARS Mask piston and cylinder head for a customer and that thing is awesome. Nice seal and quiet the pop sound a bit. Over all, if you install all your parts correctly with care then most parts should preform the way it was intended for. I've installed POS parts into a customer's gun because he couldn't afford better parts and guess what, they all work just perfectly without any problems after dumping 20-30,000 rounds. It's all about how you install parts. Just my thoughts. And for the OP, strip the whole gearbox, clean (de-grease), reinstall the parts but take your time and make sure every singe part fits and work perfectly like they should. Polish, file or cut until it's perfect. Gearbox work is never "Plug and play". Same goes for the rest of the gun.

[cjboi]

Your Hop up system is the same as the ICS mp5 hop up system. Re-install it, I had a hard time with the hop up myself before.
1st. make sure the lever works properly with the hop up spacer
2nd. fix the alignment of your hop up bucking. (put a little bit of silicone oil on the tip of your inner barrel before putting your hop up bucking on, not too much because sometimes it pushes the bucking outward)

It's easier to install to install the hop up system, the hard part is when your putting the whole receiver and the front barrel all together.

I would take a picture of my gun so you could see how the hop up system should be installed. But like I said, putting the whole upper receiver and the front barrel back together is a pain in the ass. Not hard, but annoying...

[cjboi]

Originally Posted by Amos

I'm not 100% sure on the TM Mp5 (so many different MP5 versions out there!!) but if it has a free-floating hop-up unit, did you remember to replace the spring that goes in front of the hop?

you don't even know what you're talking about and yet you always try to burn me when I try to help people.... There is "NO SPRING", now don't be a smart ass next time LALALALALAAA

like what CDN_Stalker and I said, check your hop up unit...

[THe_Silencer]

Originally Posted by cjboi

AGAIN BURNT!!!...you don't even know what you're talking about and yet you always try to burn me when I try to help people.... There is "NO SPRING", now don't be a smart ass next time LALALALALAAA...

How did an 8 year old get AVed? Here's some advice, when someone is wrong, you should tell them that they're incorrect as opposed to sticking out your tongue and waving your epen15 around. Give it a try!

[cjboi]

Originally Posted by THe_Silencer

How did an 8 year old get AVed? Here's some advice, when someone is wrong, you should tell them that they're incorrect as opposed to sticking out your tongue and waving your epen15 around. Give it a try!

ummm im not trying to start a fight here... but AMOS is always trying to assume that I only hear stuff and I dont know what im talking about. It's annoying, first of all I wouldn't have said anything if I didn't have experience with the gun. But I DO!

[Kos-Mos]

You should never have to trim the hop-up rubber in any gun.

If you do, it means that your rubber is not seated properly.

Buy an other one again and take your time to fit it. It will fit properly.
MP5 hop-ups are a pain to fit, but when you do, it solves all kinds of problems.

Again, NEVER trim the rubber. It is that length and size for a reason.

[Rabbit]

Originally Posted by Kos-Mos

You should never have to trim the hop-up rubber in any gun.

If you do, it means that your rubber is not seated properly.

Buy an other one again and take your time to fit it. It will fit properly.
MP5 hop-ups are a pain to fit, but when you do, it solves all kinds of problems.

Again, NEVER trim the rubber. It is that length and size for a reason.

Yup, kind of learned this the hard way. Ruined my new prometheus soft sleeve.

the sleeve is bunching up when trying to slip the hop up on tho. We tried using a small amount of silicone oil to try and get it on easier but to no success.

Right now there is a Systema hop up sleeve on there that is slightly trimmed where it is bunching up, not the end where the bb is fed into

[coach]

wait, you trimmed the feed lips of the systema hopup rubber too? that there is where your air is all leaking from! try using saliva/spit as lube to install the rubber into the hopup chamber. it will lubricate but dry leaving no lube.

but, by chance was any lube applied to the inner barrel? that could be the reason why the rubber is shifting when you try to install it! also try not to twist the IB too much. just enough to keep it wiggling in.