I used to have a corner in the garden designated for firing my airsoft guns into for testing etc, however, since lock down 1.0, this was re-purposed as the site for my daughters wendy house 🙁 As such, I needed to come up with an alternate solution to at least enable me to test feeding, fps etc.

My first effort was rather crude, it was an Acetech AC6000 chrono inside a foam lined plastic storage tub from Homebase. I multi tooled a slot out of the front of the tub and then glued the chrono in place. It didn’t look very nice but largely did the job however changing batteries was a PITA (due to the small clearance between the battery compartment and the bottom of the tub) and it wasn’t uncommon for BB’s to bounce back.

Whilst MK1 was largely functional, the issue with BB’s rebounding became a bit of a problem whilst working on a gun with a higher rate of fire and hence I started working on MK2 which should reduce the likelihood of rebounding BB’s and would also benefit from the following improvements:

  • Chrono mounted on lid via tripod screw and thus removable
  • Chrono to have a 3D printed muzzle cone to stop metal on metal strikes
  • Chrono to have built in rechargeable battery with vastly easier access
  • BB’s to be collected in separate area for easier removal as well as reduce BB rebounds

Unlike most of the projects I undertake, this one was fairly cheap, easy (especially if you have a holesaw and a 3D printer or have a friend who does!) and worked out exactly as intended on the first attempt!

Parts list for Chrono MK2 for anyone wanting to replicate is as follows:

  • Acetech AC6000BT Chrono – posh bluetooth version! 😀
  • Heavy Duty Hinged Lid Euro Container – 300x200x170mm (eBay)
  • Phot-R Stainless Steel D-Ring 1/4″ Tripod Mounting Screw (eBay)
  • 54mm ID Reinforced Silicone Hose 45 Degree Elbow (eBay)
  • 3D Printed Muzzle Cone (to stop gun muzzle damaging chrono)
  • 3D Printed Sleeze (to connect hose to chrono oulet)

This MK2 version has now had the best part of 3-4000 BB’s put through it at various velocities and although there is some visible wear to the first silicone layer on the elbow, it doesn’t appear to have penetrated the kevlar layer underneath (silicone hoses as used in the automotive industry normally have 5-6 layers of silicone and kevlar) but in the event I do break through multiple layers in the future I will either replace the hose or figure a way to reinforce it.

I hope someone finds this neat little project helpful as there wasn’t much out there when I looked 🙂


Andy Lee · April 5, 2022 at 12:59 pm

Hi, this is amazing and just what I was looking for! I’ve got a fair few bb’s at the back of my garden where I’ve been using my chrono and there’s always the worry that one will make it’s way over the fence.

I brought the elbow pipe and plastic container from eBay.

Do you happen to have the .stl files for the 3d printed bits please?

Many thanks


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