Silencer and inner barrel question, fps, accurace

[sebdark]

Hi,

I want to upgrade my G&G gr16 m4 Carbine CAS version.
The innerbarrel lenght is 360 mm (6.08 mm I think). The fps is around 350-360.

I want to change the inner barrel for a prometheus 590mm or 650mm 6.03mm.
I will use it with a silencer between 250mm and 300mm.
the inner barrel end is near the end of the outter barrel without flash hider (I didnt removed it yet).

How the lenght of the inner barrel will affect the accuracy and the fps.
I believe the 650 will be a lot more accurate but I am not sure if a silencer will be able to hide the inner barrel and if the fps will remain in 350-360 range.

Please help! What should I do!
I am tall, so the final lenght of the gun is not important

[Treefingers]

300mm is quite a bit of silencer for an M4, considering the gun is about 800mm long.

A longer tightbore will give you better accuracy and increase the fps roughly 10-20 depending on the quality and diameter. But the longer your inner barrel, the more you have make sure that it is very solid inside of your gun so it doesn't vibrate while the gun is in use or it'll throw off your consistency.

To be safe you could get a silencer that's slightly longer than you need, so if you're extending your inner barrel from 360 to 590 you could get a silencer that is 240 or 250 rather than just 230.

[Styrak]

You'll also need to switch out your cylinder for a non-ported one, and in the case of the 650mm barrel you may need a bore-up kit.

[sebdark]

What else should I need?
And can you link it to me by pm?

thx

[Styrak]

You shouldn't need anything else.

[sebdark]

Give a look at your pm please.