Do I really need a valve spring for a low pressure build?

[Jonnydread]

The recocking issue is normal. Low pressure blowbacks often need backpressure to recock reliably.

I'm unsure about the valve spring. I would probably keep it in there as a just in case, but my gut feeling is that it would probably function without it.

[Euphie]

I was playing around a bit a bit earlier trying to get reliable cycling at low pressure, and it would seem to me that the only way I am getting good cycling between 180-250 psi with a New Designs low pressure valve is with the valve spring out of the marker. This valve already has about as much flow as looks possible to get, and I am using a huge volume of post regulated air sitting behind the valve with both a low pressure chamber an an expansion chamber (with no ball bearings in it, so it is just an air chamber under the valve now)

My worry is, that it won't be as consistent without the spring to close the cup seal, but without a chrono it seems hard to tell if this is the case. When I had a valve spring in, it didn't seem to matter which mainspring I used it would shoot in that pressure range but, rapid fire would result in double shots and failure to recock. I plan on using a Maxflow regulator so that is why I am targeting that range, but for testing I have just been setting my Air America Apocalypse that low, I don't know if it matters but still.

Also I am noticing that at super low pressures, I can shoot paint or turn the bolt upside down, but if I just dry fire I have trouble recocking, is this normal?