Classic Army MK5

[Aaron P.]

www.airsoftgi.com/product_info.php?products_id=1418

I'm buying a used one for $140 w/2 hi-caps.

It is going to be a project gun. I want to take it completely apart and rebuild it myself so these things no longer work on magic.

Could one of you guys point me in the right direction as far as gear/piston/cylinder/motors go? Looking for cqb safe FPS (<350) with high RoF relying on the hop-up for field range and capable of taking a Lipo.

It has the stock parts in it so I'll see what it shoots like before I start tearing it apart.

[Aaron P.]

and have you guys used/heard anything about the pre-packaged modify kits?

[jhample]

buying the modify kit is probably more than you need. you dont need a new anti reversal latch. you may not need new bushings (if theyre steel their already fine plus the bushings may not even fit size not specified). spring guide only needed if yours is plastic. dont need the tappet plate unless yours broke.

you can get a spring for $10-15, a better piston for $10-15, piston head about $15-20, cylinder head about $15-20. a new cylinder is only about $10. you may not even need all these parts depending on the quality and materials of your current parts.
for the set up you want you should look for a m100 spring (~320-350fps), metal tooth piston (just the teeth you want the body plastic for speed) or nylon piston (strong plastic), you can probably keep your piston head and cylinder head, id recommend a new cylinder to ensure it is smooth (stock ones are usually brass and scratch easily with dirt letting air out) but it may not be necessary.

this is about what i have in my p90 and im getting a little over 20rps at 340fps. if you want more get a high speed motor and/or high speed gear set. thatll get you around 30+rps. as a short cut you can take off a tooth or two from your sector gear (google short stroke) only do this with a metal tooth piston though or itll snap the teeth off. itll get you 2-3rps per tooth but looses about 10-20fps per tooth

modify does make a cylinder only kit that may be a good deal. its $50 for a cylinder, piston, cylinder/piston head, and air nozzle(gains you about 5fps with an o-ring). youll probably want a different piston though.

for cheap internals id check ehobby asia or airsoft-club. american stores seem to jack up prices on parts for some reason (probably cause of their shitty customer service)

[Aaron P.]

Thank you very much for the long response jordan. I was looking at the US shops for parts so I'll definitely look elsewhere now that you said that.

Should a high speed motor always be paired with high speed gears or would I be fine with one? Should I still use a lipo with that set-up or would it be overkill?

I'll look into the short stroking; I understand the concept. I've heard of some grinding down a tooth on the piston also. What is that for?

I can't wait to tear this thing down. I'm buying it tonight (or in a couple days).

[Aaron P.]

www.airsplat.com/Items/ERA-CA-MP5A2.htm

I read this whole breakdown. Good info as far as what should be upgraded. I'll still need to inspect everything since this one is well-used.

[jhample]

if you short stroke the piston you will want to short stroke the gear too. but if you just short stroke the gear cutting the piston is not needed: