This is all stuff I have played with before.
There are some pretty good discussions about it on the US forums with replicated findings, but its always good to experiment on your own too :P
The quick reference is usually pretty close, and a good spot to start fine tuning it. Changing the DP does not make a very big difference in FPS (as seen in my pics, an increase to the DP by 13 only raised FPS by 8).
So it cant be making
too much of a difference with the amount of air being used, I think.
I'm sure you could save a small amount of air by minimizing your DP, but sometimes you need a higher DP to achieve a better BB trajectory. A loss of a small amount of shots is totally worth more range and accuracy to me.
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Fine tuning the DP is a bit of a long process. Finding the right setting gives the BB a stable trajectory and max range at that FPS.
First you choose a a muzzle energy that you want to game with, say 1.38J or 385FPS w/ 0.2g
Using the quick reference for a 300mm TBB @ 1.38J I get a DP of 18
-Set up the FCU then tune the PSI to get 1.38J with the weight of BB you are going to game.
-Get a nice long range to shoot, shoot and watch the BB path.
This is where you just play with the DP, up or down, then re tune PSI (should not change much, if at all)
Shoot again and see if the BBs path has improved or not, play around with the DP some more until you get the best trajectory.
I have seen guys post up in the US that they will get a great trajectory at X DP then as they move it up its gets worse for 5~8 DP then starts to get better over the next 5~8 DP and eventually very very good again. So there are obviously different settings that achieve the same result, so you can find the lowest one possible to save on a little bit of air.
-I have not seen this effect with my rifle though.
EDIT
Quote:
Originally Posted by ThunderCactus
EDIT; our local guy's using .28g BBBs, 45PSI & 12DP on a 455mm 6.03 prometheus and that's real close to 1.6J (420 on .20s) AND doing 1500rpm But that's on a silver nozzle.
Sooooooo you might wanna switch to silver? lol
The smaller nozzle just chokes the air volume getting into the barrel, which actually makes it less efficient. As I understand it, the smaller nozzle allows you to get ridiculous ROF, buuuuuuut 45PSI and 1500rpm is a pretty strong argument for the silver nozzle...
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Yes, I have have said before, the 'wide boar' nozzles allow you to run a much more efficient setup. There are also 2 flavors of wider boar poppet valves (gold and red) you can get that will also be much less restrictive. I have not really paid too much attention to these so I can't comment much on them.
I also usually try to stick between 1500 and 1800 RPM. Give me a very nice and crisp 3 round burst :P
If he ever moves up to 0.3g+ BBs he will probably need to increase his DP. I plan on testing out 0.30 to 0.36g BBs to see what works best for me. P* systems seem to thrive on heavy BBs so I want to try it out.