King Arms questions.
 

Hey fellas, I recently bought a King Arms armalite platform. I am looking to get some upgrades in a while, but i got a few questions.

1)Does anyone know if the upper receiver is Metric or Imperial?
2)The hop up unit is metal, should i get a new rubber?
3)Are there any air seal problems off the shelf?
Is there anything else I should look in to switching out?

Thanks in advance!

1) Metric
2) Yes
3) Yes (see #4)
4) Piston, piston head, nozzle, tappet plate (alternatively you could bend it straight), spring guide

The trigger harness/ block/ contacts are pretty awful, so you should plan to replace them at some point if not now.
SHS is a straight drop-in.

metric or imperial?

Replace the cutoff lever at some point too.

Pretty much everything these guys have said.

They're a good starting point for builds though, in my opinion.

cutoff is pretty soft, it wears out after half a year to a year. If you're in the gearbox you might as well just do the list that stealth mentioned, plus a good bevel to pinion shim. They can get pretty quiet when properly done.

I agree 100% with the above responses.

In addition to all of the above suggestions, a common drop-in that I've upgraded for many (former) clients was a high torque motor. Depends what spring is in your KA though, the ones I used to work on were the early ones in Canada during the time when most imports came in with higher FPS (~3 years ago). Stock KA motor is fairly anemic for the M120-M130 springs that they used to be shipped to Canada with, even with 11.1V LiPo packs.

On the topic of air nozzles, those KA/Cybergun Colt M4's from 3 years ago occasionally had feeding issues out of the box due to off-spec air nozzles that ran a tiny bit longer than was necessary. If this is still the case, do get the shorter variant of M4 air nozzle - in Guarder/Prometheus terms it is labelled as for M16A1, not M4A1.

It shoots 340-400 fps, figure this is one of those puppies speak of.

if you have a fps spread of 60 fps, you have shit air seal. lol.

oh typo! thanks for the help! I can finally execute my plan with precision.