Ideal Inner Barrel Length (Spring BASR)

As i promised before, here are another post about Ideal Inner Barrel Length for Spring BASR.
Being different in design, tuning Spring BASR are slightly more tricky than AEGs. (Check out Ideal Inner Barrel Length (AEGs))

As for maximizing inner length to achieve optimum FPS, longer range, better grouping, and less noise when shooting, we need to set up our cylinder to be having 2.4 x more volume than inner barrel. Many senior airsofters has proven this to be the best ratio for high performance Spring BASR. (i worked all BASR my guns based on this too, and it works ! :D)

Basically, we need to work our compression parts to achieve the "Perfect Cylinder-Barrel Ratio" of 2.4. Don`t worry, i`m not a mathematician either, so i will explain these calculations in simple yet understandable manner. To make it easier, i have prepared some picture,

Still confusing?? 

Let`s make some simulation.

Say we`re building a VSR-10, we already replaced cylinder head, piston, etc, and now we need better barrel.

1.First of all, decide which inner barrel diameter we want, for example 6.02 mm

2.Next step, calculate our cylinder volume with first formula on picture where D stands for cylinder Diameter, and L stands for Length (please start to measure the length from end of port/hole on cylinder to top surface of cylinder head). On our VSR rifle we have cylinder diameter of 22.3mm, and compression length of 96mm, so (3.14 x (22.3/2)²) x 98  =  37.475

3.Then, use last formula to calculate best barrel length.

 (37.475/2.4)/3.14/((6.02/2)²) = 548.867

So using 548.867mm x 6.02 inner barrel would be the best for our current gun ! :D. But you can also improvise by rounding up to 550mm to make the ratio shrink to 2.395 (less ratio usually means lesser noise when shooting, but too low will drop fps too), or go with 500mm to make higher ratio (more power to use heavier bb`s, but more noisy). Ratio of 2.4 is not absolute, you can add up or  subtract a bit towards your preference.

Thats all for today`s post, read again from beginning if you dont get it, but if there`s any question, feel free to post, i will answer as soon possible. 

By the way, Happy Sunday! :D