How much help a bore-up kit does?

[DYORD]

I'm planning to upgrade my cylinder, nozzle, etc...

[CDN_Stalker]

Only get one if yo uare going to be using an insanely long inner barrel, like over 650mm or something. Longer barrel will have higher internal air volume, therefore you need a higher amount of air volume in the cylinder. If you don't get the bore up kit for a super long barrel, the BB will get pushed through the barrel by the amount of air that was in the piston, but will get near the end and start to slow down because of not enough positive airpressure behind it, closer to a negative pressure.

That is a raw description, I'm having my first coffee of the morning, but gives a rough idea of what is known as "barrel suck".

[joker060]

Sorry to Hijack here but I have a question.

When adding a longer tightbore to a short gun (MC51), how long can you go before you need to add a bore up kit? I want to add a silencer to my MC51 and have the barrel in the silencer but would like to avoid the bore up kit.

Once again sorry for the hijack. Just couldnt find my answer anywhere else and this was a close as it got.

[Endymion]

You really shouldn't need a bore-up kit until you exceed 590mm, and even then you would need to be running an M120 spring at minimum in order for it to work.

Anything past an M4-length barrel and you'll probably want to consider an unported cylinder.

[CDN_Stalker]

Originally Posted by joker060

Sorry to Hijack here but I have a question.

When adding a longer tightbore to a short gun (MC51), how long can you go before you need to add a bore up kit? I want to add a silencer to my MC51 and have the barrel in the silencer but would like to avoid the bore up kit.

Once again sorry for the hijack. Just couldnt find my answer anywhere else and this was a close as it got.

Ya, as the previost post, for a gun with a barrel up to 470mm long use the ported cylinder (hole near the rear, noticed the MP5K has a hole in the middle of the cylinder), over that up to I guess barrel length about 590mm long
use a non-ported cylinder, after that a bore up comes into play due to the increased internal volume of the long inner barrel.

[joker060]

Okay because my stock barrel is 285mm and I am looking at going to a 363 barrel. I'm also going to go with a Guarder cylinder enhancement kit though.

[CDN_Stalker]

Just need the standard ported cylinder for that.