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Well Mb09 - Final Upgrades, Shortening Barrel, Volume Matching Help?

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This is my current Well MB09 setup.


Stock Outer Barrel, Receiver, Stock, Hop Block, Hop unit and Bolt handle end cap.

Action Army EG Barrel for VSR 410mm.
Maple Leaf 60 degree bucking.
AirsoftPRO Full upgrade v4.1 zero trigger set
AirsoftPRO U shape hop arm
AirsoftPRO Cylinder with Sorbo installed for an airbrake.
AirsoftPRO Piston
AirsoftPRO Cylinder Head
AirsoftPRO Bolt handle


Currently shooting just below the UK Joule rating on .48's.


So I have been very unimpressed with the amount of flyers and general inaccuracy I get with it. Due to the fluted Well barrel, I have to stick with the original hop unit, which although TDC'ed and installed with a nice arm and shimmed, it seems to perform flyers on a regular basis.


The AP Air seal components are really quality, however they generate slightly less volume then standard VSR components due to thicker cylinder walls and smaller diameter piston. It also has a piece of sorbo to bring the FPS down a little. As such the 410mm barrel is too long to get enough volume for .48s to be stable.


So I am considering a shorter barrel setup with the following parts.


Maple Leaf VSR CNC Receiver Type B
Maple Leaf Bull Outer Barrel 300mm.
Maple Leaf 300mm Crazy Jet
Action Army VSR 10 Hopup chamber.


I have to keep the stock Well Hop Block because the MB10's mag release mechanism is built into the Block and not the body.

I would prefer to not have to buy the ML receiver, but I believe the Well receiver is off spec and will unlikely be able to take the ML Outer barrel.

I will likely pick up some Bull barrel stabilisers as well.


Does anyone see a problem with this setup at all? Can I reuse my Well VSR Rail on the Maple Leaf Receiver? Considering the AP Cylinder has slightly less volume then most VSR's and a piece of sorbo has been installed for an Air Brake, will I be close enough to volume matching with a 300mm 6.04 ML CJ barrel?


There is a cheaper way of doing it, simply buying a Well MB02 for cheap, and just use the outer barrel from that, buy the new inner barrel and AA Hop unit and be done with it.. Sadly Gunfire has none in stock for the silly cheap prices Well MB02's go for.

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Measure the inner diametre of the cylinder and the piston travel. Subtract the airbrake length from said travel, calculate cylinder volume.

At least it's what I did with my T-11, piston travel on a vsr is roughly 90mm and the ratio for a 0.48 should be around 3.5:1 (which is only a guess as 1tonne's guide only goes up to 0.45g, either way a slightly overvolumed gun isn't bad at all)


maths are cylinder radius^2 x piston travel length x pie / barrel radius^2 x barrel length x pie


With my setup (TM spec cylinder, an effective travel of 66.2mm, 6.03x300AA inner) I have a 3.21:1 ratio, but my airbrake is 24mm long.

With an airbrake, sorbo thickness is irrelevant as the actual useable volume ends when the airbrake enters the nozzle.

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