King Arms P90 Upgrade Help

[AlexBisnett]

So ive decided to keep my p90 and just put some money into upgrades so i can keep this p90 as my primary. I was deffintly thinking of getting a tbb extended into a silencer. I also want an optic so i can line up shots a little easier than using the so called iron sights built into the gun.

Ive attached a red dot onto my p90 before but it was way to high. Is there any smaller optics that will actually line up with the shots? (Ive got the tri rail KA p90) Can someone recommend the best hop up bucking for p90s, i know bucking makes quite a big difference. Other than that if someone can suggest some other upgrades that would improve range and performance that would be great.

[redzaku]

the smallest red dot is a mini reflex red dot
you can try using a heavier bb, like .25g for range
and that is all you getting from me, others will come bearing gifts for your actual rifle

[Kos-Mos]

I had a Tasco 30mm RDS on mine, it works fine.
My friend uses a Aimpoint M2 replica with a L-mount, also fine.

If you are using a good quality RDS and know how to zero a sight, it will align.
The thing is because of the large distance between the bore and sight, you can't adjust the sight at close range properly.

Then again, even with a P90, you should not zero under 100 feet.

[lurkingknight]

zero to a hold over... really the only way to deal with the p90's height over bore.


so take your dot and measure the height over bore.. say it's 4 inches... at 30 feet you want to aim at a point 4 inches over where you actually want to hit.

at 60 feet, it should still be 4 inches over where you want to hit. etc all the way to your max range.

true zero on a p90 will suck because that means the line of your sight will eventually have to converge with the path of the BB... which means if you shoot at something beyond that convergence, your BB will now fly OVER where your sight is zeroed to so it has a chance of riding up higher than you want. This is not a problem if you know your ranges well.. but if you rig it so the gun will always shoot whatever the difference your height over bore is from your sight, you'll always shoot that or drop it so all you need to figure is how much to lob a shot if you're shooting at a point where your flat flight starts to drop.

[Krawch]

Definitely recommend getting an extended tbb and trying out an r hop bucking if your internals are at the fps and reliability you like don't touch it until something breaks I'd go with a Prometheus 6.03 with r hop you will have some of the best range and accuracy on the field as for optics I am done using anything other than my irons if you speak to a lot of airsofters they don't even turn on their sights they just use them for show you can't see as easily where your bbs are landing if you are dead set on a red dot check out the NC star multi reticle reflex sight its pretty slim

good luck

[AlexBisnett]

Thanks for all the help guys. Probablly wont end up getting a prometheus barrel, but something along the lines of a madbull 6.03 my local store has in stock. Should i buy the premade z kit for an rhopped barrel, i was looking at them a while ago but ended up just getting a flat hop for my m16.

[lurkingknight]

people just throwing in an rhop aren't going to see maximum benefit... it's the LAST thing on the chain to upgrade. The compression needs to be solid < +/-5fps before you get the most out of your rhop.

Also there's no such thing as an rhop bucking. it's a patch that you put in your barrel and you make the bucking yourself by shaving the mound off a standard one. Unless you want to overpay for a flathop bucking.

If you go rhop though, pay for the prommy barrel.

[AlexBisnett]

Ok thanks for the help guys. For everyone who has ugraded their p90, since the original inner barrel length of the p90 is 247mm and im looking to get a tb barrel that is m4 size, 363mm will i need to change any of the internals other than that?

I randomly seen on another forum someone upgrading a g36 which has the same inner barrel and someone was telling them they need a bore up kit? Would i need one of those with my p90?

[Short Round]

Originally Posted by AlexBisnett

Ok thanks for the help guys. For everyone who has ugraded their p90, since the original inner barrel length of the p90 is 247mm and im looking to get a tb barrel that is m4 size, 363mm will i need to change any of the internals other than that?

I randomly seen on another forum someone upgrading a g36 which has the same inner barrel and someone was telling them they need a bore up kit? Would i need one of those with my p90?

Yes, if you put a m4 (363mm) barrel into a P90 you SHOULD change the cylinder in the gearbox so the port matches the barrel. You could run into FPS inconstancies if you don't (I did at least, along with many other problems).

You don't need a bore up kit, just stick with a standard kit/parts. It always doesn't hurt to have a box full of spare parts just incase something breaks. (Here is what a bore up kit is essentially >Click Here < )

Make sure your Airseal and Shimming are perfect. I found these two things alone are essential to make a gun perform to it's fullest ability. You'd be surprised what your gun can do when you do these things even with stock parts in it.

If you don't know how to do it, find someone that knows how to to do it for you. I have been playing for 3 years, and I still get someone else to maintenance my guns (because I am lazy and I have no concept of how science and engineering works, I just assume it is all black magic).

Learn from my mistakes, don't use a P90 for 2 years with airleaks, an inconsistant FPS, and misfeeding like I did. Good luck.

PS. Consider getting a mosfet, it will give you a little better trigger pull and prolong your trigger contacts.

[lurkingknight]

long story short, unless you go with a barrel longer than 450mm you don't need a bore up.

the m4 cylinder is a good idea, but honestly a good 247 is just as good. barrel length doesn't mean as much in airsoft as the straightness/smoothness of the bore. I have a super upgraded p90 with a 247mm barrel that shoots just as accurately as a super upgraded g36 with a 407mm barrel.

[AlexBisnett]

Ok, so i would be alright if i threw a 363mm barrel on my p90 without changing the internals? Like is it necessary to get an m4 cylinder?

[AlexBisnett]

Hey sorry ive got another question guys. I picked up a silencer and 363mm tight bore today, tried changing the barrel but after taking my hop up apart im not sure if i lost the nub or what? I thought the nub was built in with the stock king arms bucking thats kind of like teeth but maybe im wrong. Anyways ive installed the bucking back in but when i put the clip and hop up ring on im not able to turn the hop up on or off. Either way it just doesnt let me turn the ring... not sure what i did? hopefully someone can help me :banghead:

[lurkingknight]

you put the ring on wrong. also you lost the nub and it's a good idea to upgrade the cylinder to an m4 length one.

[AlexBisnett]

I fit the ring in right.. and i just put a tiny dab of super glue and glued the nub on the hopup arm.

[DustMagnet]

Originally Posted by AlexBisnett

im not able to turn the hop up on or off.

Ring doesn't move, or when the look down the barrel the sleeve is not pushed into the barrel as ring is turned? If you take the ring off can you move the lever up and down? When you turn the ring does the level move up and down?