Advice on these upgrades needed
 

I'm planning on doing another round of upgrades on my TM MP5. So far I've got a bearing spring guide, Modify 100 spring, and steel bushings. I need some more range and accuracy, so here's what I'm planning:

Mad Bull Quicksilver Black Oxide Silencer (157mm)
Mad Bull 6.03mm Tightbore Barrel - 509mm (cut down to approx. 385mm)
Prometheus Air Seal Chamber Packing (Hard Type) Hop Up Rubber

I'm considering the following:

Modify 110 Spring
Modify Polycarbonate Bearing Piston Head
Modify Air Seal Nozzle - MP5 Series

I'd like to get some advice or approval regarding these parts. Is my barrel length okay? Anybody know if the Modify Poly piston head is any good? Should I consider any other parts? Would a polycarbonate piston reduce wear on the gearbox?

I'd like to be able to get everything I need from airsoftparts.ca

Much appreciated!

Grimm I would suggest some metal bushings, shimms, to properly shimm the mechbox.. Also you can just buy a 400+ MM barrel and its less cutting and less cost imho. If you have the MP5 SD you can get a barrel that will basically go just too the end of the silencer.

Everything else looks good. The modify head is a great add on.. I have one in my ICS and its taken alot of abuse. I would however suggest a guarder clear rubber instead of that hard type.. Those are mainly made if my thoughts are correct for 400+ AEG's.

Your accuracy will tighten a bit with the 6.03 but range you might get a bit further..

Sounds good. Why don't you buy an M4 length barrel instead? 343mm is close to what you want and you don't need to do any cutting?

Don't cut down Mad Bull barrels, they're teflon coated and it'll likely get damaged.
There is a 363mm length available and it's not far off from your desired length.

I have installed metal bushings and re-shimmed the mechbox. I'll also need to re-grease it since the last time I was in there it was looking a little dry. About the hard type bucking...I was thinking with the other upgrades, I'd end up around 400 fps? Right now it's shooting about 330 fps. The compression could be better; hence the piston head and nozzle. The stiffer spring, better compression, and tight bore I thought would bring me up to 400 fps?

I'll go with that one then.

Systema silent piston and cylinder head - much easier on the mechbox under a tight spring. May as well then buy a systema cylinder so that they all fit better. Also buy an extra piston to keep as a backup, may as well also grab 2 hop buckings too because they're cheap.
Definitely buy the 364mm barrel, 2cm isn't going to make any difference.

I don't know what is out there for replacement hopups on an MP5, I'd like to replace mine but can't think of any brands at the moment.

I may just take that advice and go with the silent head set. I don't think there's a suitable systema cylinder at airsoftparts.ca though.

I was also wondering about a better hop-up unit. I'm sure jugglez knows what's available?



Soo....what's the point of a polycarbonate piston? Is it just to improve ROF? Will it reduce impact on the gearbox at all?

There's nothing wrong with the MP5 hop-up unit, unless yours is broken why replace it?

Your TM original piston is actually a very good piston, run it till it breaks.


Go with the Modify Piston head with sorbo pad, much cheaper option than a Sysema Silent head set and works just as well.


For hop-up rubber Guarder Black should be fine.

You're all set...just stick with a 343mm barrel and don't sweat the little bit shorter barrel.

If you're compression is good and your nozzle/hopup seal is good, you should end up around 400fps with 0.20's.

Note, if you go with a M100, you'll be in the high 300 fps and you're trigger response will be better and your ROF will be higher than with a M110. Battery and motor will last longer as well. And no risks that you'll chrony over 400 (don't know your field limits but it's 400 around here).

Best of luck...

Well I couldn't afford $200+ for upgrades this week. So I bought the silencer, tightbore, and hop-up. The mechbox upgrades will have to wait until next paycheck.

Anybody anticipate me having a problem with the new length barrel and my stock cylinder? It would be a royal pain in the ass to install it, find out it's sucking bbs, and then re-install the old one.

Madbull are just aluminium... Prometheus are stainless steel. There one brand that makes a Teflon coated one but as far as i am awaure its not Madbull...

gee thanks :P

I'm not sure with the Modify Piston Body brand, but Polycarb Piston Bodies does not necessarily reduce the wear on the mechbox but to the Piston Body itself. If its polycarb, I guess its better than using the stock TM Piston Body. As for the mechbox, proper shimming and use of metal bushings would reduce the wear on the gearbox. What is the equivalence of a Modify m110 spring to a let's say Systema Spring. If I'm not mistaken, A modify m130 is the same as a systema m150 which produces 550 fps. If a Modify m110 is the same as lets say, a PDI 190 Spring or a Systema M120, then its safe on your mechbox. And regarding the hop up rubber, i advise to use a softer bucking than the Prometheus since you would be using a softer spring. Regarding the tight barrel length, i suggest you either use a Type-2 or Type-0 Cylinder, just experiment between the two and use whichever yields the higher fps. I bet my money on the Type-0 with that barrel length.
And properly seal all airleaks.

I meant the snide remark is a good way...LOL.

Upgrading your AEG (and kudos to you for figuring it out and doing your own!) can be both rewarding and massively frustrating at the same time. There are some general guidelines for good setups...but most times you just have to try it out and see what you get.

Because of the slight variances with all the parts and the number of things that can affect the end result (be it FPS, accuracy or ROF) it's near impossible to say..."add part X and you'll get result Y".

Obviously some rifles are easier than others to work on...unfortunately, with a TM MP5, you've got to take out a good number of screws and split it in half to get to the goods. And just when you think you've got it...you strip screw hole threads, or drop one stupid little o-ring and can't find it, or slip with the screwdriver because you're rushing it and scratch the finish, or any other bone head thing.

The worst part (if you're obsessive compulsive like me) is when you have your rifle setup perfectly...and then tear it all apart again just to fiddle with something else for the hell of it! LOL.

Then you end up with enough spare parts to almost make another one...and it starts all over...

Last week I bought a SAW...70% of the reason I bought it was for the quick change spring feature. I've got about 30 misc springs that I want to chronograph and I don't want to have to disassemble my M4 just to try each one of them out!

Doubt you would have to worry about barrel suck at 385mm unless you are using a crazy ROF setup.

http://www.airsoftforum.com/board/in...#entry17451171

Same reason why I go for AEG's with Version 3 gearboxes. Much easier to maintain. :)

Sold a spare AEG this morning which allowed me to purchase my mechbox upgrades. Here's what's going into my MP5 as soon as they arrive:

1 ea. G&P AEG Grease Set
1 ea. Modify Enhanced Tappet - V2
1 ea. Modify Air Seal Nozzle - MP5 Series
1 ea. Modify Enhanced Cylinder Head - V2
1 ea. Modify Enhanced Cylinder (300mm-450mm)
1 ea. Modify Polycarbonate Bearing Piston Head
1 ea. Modify S110 AEG Upgrade Spring
1 ea. Sorbo Pad for V2/V3 Cylinder Head

in addition to the parts I already had ordered:

1 ea. Mad Bull 6.03mm Tightbore Barrel - 363mm
1 ea. Mad Bull Quicksilver Black Oxide Silencer
1 ea. Guarder Improved Hop-up Set - Black

The tappet is a backup. I am likely going to wait on installing the 110 spring until I chrono with the compression upgrades. Right now my ROF is 760 RPM, and the real-steel is 800 RPM so I don't want to loose ROF if I don't have to.

why not try the mad bull shark hop up bucking. stops double feeding and increases fps

I accidentally chose the wrong shipping method for my barrel and hopup. They haven't arrived yet. But yesterday I installed my new cylinder, piston head, cylinder head, sorbo pad, and nozzle. I re-greased and re-shimmed the gearbox perfectly. I think I even ended up with a better ROF. Here's the weird thing though....my velocity decreased. I tested the compression with the new parts, and it was awesome. Better than what I took out.

So how the hell could I end up with decreased velocity? I can't figure it out. Tested in semi-auto...

How much did it decrease by?

And stay away from the Madbull hopup sleeve. Never heard a good review.

dont get the air seal nozzle with prom air seal hop rubber.

you will have jamming problems like there's no tomorrow

I can't say for sure as I haven't chrono'd. All I know is that it was penetrating a piece of insulation foam before, and now it's not.

did you change the hop up rubber yet?

maybe you installed the spring backwards

maybe you installed the cylinder backwards

I installed the spring with the more compressed end to the rear, and the cylinder with the port to the rear.

Doesn't seem to be a major decrease in velocity. If I wasn't using the insulation foam as a target I don't think I would have noticed. I was really hoping for a performance increase though....

Check the nozzle you installed with the stock nozzle to see if the modify one is shorter. If it is shorter then it won't completely seal with the hop up rubber giving a good "kiss" to seal, decreasing your FPS.

I think this is the problem...but the air-seal nozzle is the same size as the one it replaced.?? I ended up re-installing the stock nozzle. I've replaced the hop rubber, and have made sure the mech box and all parts are seated properly. With the nozzle completely forward, I can see that it's nearly 1mm away from the lip of the rubber. I was thinking of buying a longer nozzle designed for another gun and sanding it down?

Is your hop up chamber metal or plastic?
Because if it is metal, you could shave the 1mm from the tabs and that would bring back the hop up chamber back closer to the mechbox and hence give you a good nozzle seal. I did this with a metal chamber.


shaving from the plastic hop up chamber tabs could be risky and result in broken tab and you buying an whole new chamber.

I was tempted to take my nozzle to a seller to try to match it with a slightly longer nozzle but I would have to bring the cylinder head too in case the nozzle inner diameter is different. Anyhow that was to much work for me.


oh and make sure the anti reversal latch is fully off the gear (and pull the nozzle forward by hand) when testing distance of the gap. The nozzle has to be fully forward or it will trick you into thinking the gap is huge.

the hop up unit is plastic, but there's not enough material to remove to bring it any closer. I can't think of any way to mod it.

I actually took the mech box apart and made sure the tappet was all the way forward. I put it all back together very carefully making everything fit as best as possible. Then I flipped the gun over, shined a flashlight down the barrel, and looked through the mag well into the hop up unit. It's a significant gap (almost 1 mm) and it certainly isn't sealing.

Well then for significant gap of over afew mm, get a longer nozzle would be my best suggestion rather than filing a mm off the tabs.

One guy filed the tabs off completely to make sure the hopup chamber sat flush against the mecbox. I think he may had too much problems with it then got fed up and filed off the tabs. He might have even filed the chamber slightly IIRC. My concern is keeping the chamber from rotating in that extreme "solution".

I'm surprised the fit is bad on a TM. Might have expected that on a china clone. You absolutely sure the gap was there before with your old nozzle, and is the gun is assembled correctly. Was it firing poorly before too? I wonder if replacing another part would get rid of the gap. Might consider getting a second set of eyes like a gun doc to have a look at it.

it's possible that the gap is in the hop-up unit. between the retaining clip and the actual hop-up unit. i'll take it apart again and see if I can get things a little more snug. there was a gap in the stock hop up assembly and I thought the barrel was as far into the hop-up as it could go....but i will try again.

Yep it just needed a little bit more forcing. It's shooting nice and hard now. Can't wait to field it. :)

Congrats! Good to hear it is ready for action.

Even in computers so many times people call me and I always ask "you sure that its assembled correctly" --80% of the time I get a call back saying they forgot a power connector on the mobo or video card. After that boot up is fine.

Poor man's chrono puts it over 385 fps (penetrates the bottom of a pop can). I was aiming for somewhere between 380 and 400 so I'm happy. :D That's with the Modify 100 spring too so I still have great ROF.