Upgrading MP5 A4 (any tips from the pros?)
 

Well, I'm starting fresh with AEG's, just picked up my first one and instead of buying a nice new expensive and good one, I want to learn about what I'm using so I decided to by a crap broken one and upgrade it. I picked up a used and abused UTG MP5-J. Already changed the front grip to a new grip with tac light, ordered a new metal CA cocking tube and cocking handle as it came with a broken cocking handle and bought a full stock with wires to replace the broken adjustable stock. I rewired her to the rear and want to run a larger battery in her. I was looking to run about an 8.4v 3000mAh battery and I've been reading tons about what upgrades to do and what needs to be changed from stock if I upgrade the battery, and I just wanted some input from the pros or people who have done it!

I know I'll need to do the spring, I'm looking to put in a PDI 120 or 130% spring or something of similar power, and I've read it would be wise to up the stock 15amp fuse to a 20 or 25. I've heard the MP5's are a bugger to get open cause you have to split the body completely in two to get at the internals but I'm willing to do it because I want to build a good gun and learn at the same time. Any other comments or recommendations from you guys would be MUCH appreciated. Thanks

use a prometheus spring instead.much better.

You're not the first person to say that. I think I just might. The Prometheus MS110SP seems to be getting some good feed back from what I've read online.

Prometheus 110 spring period.

I'll tell you something. PDI springs are very inconsistant (do you want 350fps or 425fps? Get a PDI 150%). I installed a GOOD (350fps on the nose) 150% spring in my first MP5, within two months of shooting in the basement (was over the winter) my stock mechbox broke bad. So I bought a Hurricane reinforced mechbox (very good mechboxes!) and it lasted me about two years worth of playing, then busted (remember, reinforced mechboxes just take longer to break) that one too. Now my MP5SD is in pieces waiting to order a new box. Mind you, I was getting 352fps for the first while, put in a bearing spring guide knocked me up to 365fps, and I put in a 330mm inner barrel took me to 387fps last time I chronied it high.

I got a well beaten former rental MP5A5 last year, stock mechbox, and I upgraded it with only metal bushings and a Promtheus 110SP spring, I've been using it all year (that's what, 15odd games?) and it's still going strong, mechbox is intact still and still chronies at 365fps with 0.20g BBs.

Decide what fps you want out of it (if you say 400fps I'm gonna slap you ;) ), then we can help you along the path of basic cheap upgrades. I have no idea what standing or parts are required for the UTG brand, but at least yo uhave a clearer picture of what to get and what to avoid.

I'm looking around 350 or maybe a little less or more. It'll be a CQB type weapon, nothing overly powerful and certainly not a sniper. I just want a solid performing AEG. My plan for this gun was just to learn, period. I eventually want to build her into a "sleeper" mp5. A UTG MP5 that can hold up to a stock TM with a metal body. I want to have her firing really well and consistant but I want to do it all myself and learn a ton about her in the process. I've been studying the mp5 take down video like it's the bible learning about taking it apart, so i started with light upgrades like the body and battery and such, now I'm gettin' down to the good stuff. Spring and possibly gears or pistons or a whole new mechbox if need be. I'm looking at metal bushings, spring, and bearing spring guide as my first upgrades? Wise? Easy enough to start with? Any tips on brands or specific parts?
Thanks guys

Get a Prometheus 100SP then, skip the bearing spring guide and get metal bushings, that should be all you need. Putting in a 110 spring and bearing spring guide might easily knock you up to 380fps with 0.20g BBs, NOT what you want with a CQB gun. A 100SP and bearing spring guide might net you 340-350fps, but if it's mainly for indoors, stick with just the 110SP spring and metal bushings. Like I said, have no idea about the UTG parts, but it's safe to say that you should stick as many TM parts in there as possible (within reason) to make it more reliable. Aftermarket parts can be ver finicky (I've had MORE problems with upgrades and reliability using aftermarket parts than stock TM ones).

Hmm, thanks for the imput. So I need to track down a Prometheus 110SP spring and TM Metal Bushings. Alright.

I don't think you can find TM metal bushings, just get whatever is in stock from where you buy the 110 spring. Just need to be 6mm metal bushings, doesn't really matter what type as long as decent quality. Contact Jugglez at airsoftparts.ca and get your stuff form there, great prices and Jugz is always on the ball for customers.

Jugglez is who I got my stock from! I've been chattin' with him about parts for a while now. Okay, so I need a 110 spring and metal bushings. Think that would keep me happy for a while or are there any other simple, not too expensive upgrades you'd recommend? Thanks so much, Stalker.

All that should be just fine for your CQB gun. You could put in one of the cheaper tightbores that Jugz (VERY good retailer, stick with him!!!) sells, maybe a better hop up rubber set as well. Literally, I doubt you'd need either, but they won't cost you much and will still be useful for CQB, in that if you see foot sticking out from cover 60ft away, you'd have a better chance to tag the dumb bugger with a couple shots instead of a lot. Lol

Hmm, I guess for now I'll go with that and learn what I can while installing it all. I'll see where all that gets me and how I like it and go from there. Thanks for all the help. Man I thought this gun would cost me a lot more than this. And before I forget the only other thing I need that I haven't decided on yet is a battery. From what I've read and heard, I'm looking at at upgrading to a large type 8.4v 3000mAh battery (from a small type 8.4v 1100mAh battery). From what I've read it'll last me a whole day of playing and a better rate of fire. Sound good?