If you are going to run it on CO2 that expansion chamber will work fine, especially with an anti syphon tank. I had a similar set-up on my mag (it's an old school set-up called a micro-knight basically a 3.5oz CO2 tank mounted vertically as an expansion chamber/foregrip).
A couple of things you might want to consider:
-You can't shoot down too much so be careful if you are palying on an urban field shooting from a second story window or something similar. The expansion chamber will fill up after a few shots & you will get liquid in the valve.
-You might want to thing about installing an on/off valve (something like this: https://www.palmer-pursuit.com/ecom/images/DSC01821.JPG
) between the ASA & the line to the expansion chamber (that or buy stock in a bottle-oring company) as you will chew up a lot of bottle o-rings unscrewing the bottle with an expansion chamber probably 1/3 full of liquid on the gun side of the ASA. Be careful how you use it though. Fill the expansion chamber with liquid, close the valve, let the marker warm up & you have a dangerous situation as there's no burst disk to protect you.