8mm Chamber Size

[Mitchza89]

Hey guys,

Yet again I'm planning a new bb rifle cept' this one will be 8mm. I plan to use 1/2in galvanised pipe as the chamber. It's going to be a coax like my copper n' brass 6mm. Anyone have much of a clue how long to make the chamber if my barrel will be 1m? I'm thinking 20-30cm

Thanks alot.

[jackssmirkingrevenge]

I'm guessing it's going to be pressurised with a shock pump? If so, make it as big as you can afford to pump. I find that around 4 cubic inches is the most I can take to 350 psi without my arms falling off, so in your case that would be about 80cm (as a coaxial)

[Mitchza89]

Oh wow thats alot more then I thought haha. I wanted to try and make the chamber aslong as possible so it protects the barrel alot better. Because the chamber on my 6mm was so short, the barrel got knocked around and bent very easily. At the moment, I'm gonna be using my bike pump beacuse that can get me up to 150psi in 3 pumps. I don't want to go any higher at the moment because of the noise (Luckerly I'll be moving to a 1 acre block on an island with 70 acres of vacant land next door that I'm gonna turn into a shooting range ) But untill then, I have to be quiet with the guns.

[jackssmirkingrevenge]

A bike pump isn't such a chore - why not go as big as you can, and just use it at lower pressure for now for noise suppression reasons?

[Marco321]

I'm guessing it's going to be pressurised with a shock pump? If so, make it as big as you can afford to pump. I find that around 4 cubic inches is the most I can take to 350 psi without my arms falling off, so in your case that would be about 80cm (as a coaxial)

Do you mean 80 cubic centimeters or 80 centimeters long?

[jackssmirkingrevenge]

80cm long assuming a 1/2" chamber with an 8mm barrel through it.