Bore up kits?

[hapi]

Hi

Can anyone tell me if there is a difference between a bore up kit for an M16A2 and M4A1. The only thing that I can see is the M4 kit has some hole in the cylinder

Thanks Guys

[richardy]

Re: Bore up kits?

thats exactly it

[hapi]

Re: Bore up kits?

Do the holes make any difference to the performance?

[richardy]

Re: Bore up kits?

They reduce the amount of air in the cylinder, thus lowering the fps. Obviously depending on the position of the hole. The piston/head won’t start compressing till it gets past the hole. Generally you match ports to barrel sizes.. the longer the barrel the more air you need.

over 300mm barrel you’ll need a full cylinder all the way up to 500mm, more than that you will need to go for a bore up full cylinder kit. I say need, its recommended as with most things in Airsoft, no ones actually sat down and worked out the cubic volume of the barrel and the cylinder and compared the too, its only what’s recommended.. and what i do.

There’s benefits to ROF and efficiency by adding ports and shorting the amount of air that needs to be compressed so a fully cylinder isn’t always the best option.

bore up kits require a larger spring to operate fully they simply work by using a larger volume cylinder and a larger o ring and air nozzle. Without a decent spring power creating a good air seal can be problematic.

[North West Outpost]

Re: Bore up kits?

The ports in cylinders are to match the air volume in the cylinder to the volume required to make the bb exit the barrel.


They should match as close as possible to give the best performance. If there is more air than required it has no ill effect, unless you want the max rps out of your gear box then they are better matched.

On the other hand, if there isn't enough air for the bb to clear the barrel, there will be negative pressure produced by the reverse motion of the piston, slowing the bb, so there will be a reduction in fps. Very dependant on the ammount of missmatch.

The bb needs to clear the barrel befor the piston is reversing.

[hapi]

Re: Bore up kits?

Thanks for the info, I have just put a TB barrel in my CA scar and the effect was negative so I think i will go for the M16 cylinder kit see if that helps