Need help! Bottling cocktail sodas

Im trying to bottle cocktail sodas using a kegg and letting it sit for 5 days at 40 psi, then dispensing using a beer gun at 5psi. I vigorously shake the bottles to make sure theres no bubbles escaping. I make sure the bottles are filled to the top( no head space?). My problem is that im not getting the right amount of carbonation. Im contemplating in using acacia gum or maltodextrin???? Or if the bottling process needs adjusting?????

Your 5 days at 40psi may not be getting you where you want to be.
Find a CO2 volumes chart and find the appropriate carbonation level, I'm guessing you want to be in the high 3's? Based on the info that you find on the chart and the temperature that you'll be carbonating, make sure you set your regulator a bit higher as you'll lose carbonation transferring from keg to bottle, and then again to pressurize the headspace. (oh, wait, just reread that you have no headspace).

When carbonating, if you have the temperature and pressure set for your desired carbonation, there's no harm in shaking the keg to get it to carbonate faster. Sounds like you certainly don't run the risk of overcarbonating. The only time you would overcarbonate something is if you set your regulator way higher than the level of CO2 you're aiming for. Give the keg 10-15 minutes between shaking and bottling so you don't get too much foam.

Acacia gum or maltodextrin may compound the problem, as they will result in more foaming.

Thank you for the feed back! My questions to you is, do you pressurize the bottles with c20 before capping ? I know that's its necessary to do so before inserting liquid in bottle? (I have a beer gun). And do you mean raising the psi when inserting the liquid? If so, doesn't creating foam in the bottles =lost of carbonation?

There's really no way to pressurize bottles before capping, as you'll just release that pressure going from your filler to the capper anyway.

That said, you don't necessarily need to pressurize before putting liquid in, either. If your filler has a stopper, then as liquid enters the bottle, the air it displaces and compresses functions as the counter-pressure. (I've never used a beer gun, does it have a stopper?) Your filler will stop once the air in the bottle is compressed to the same pressure that's on your keg, so a slow release of pressure will slowly fill the bottle and thus reduce foaming by keeping a slightly higher than ambient pressure on the liquid as well as decreasing turbulence in the bottle.

The only reasons to pressurize before filling would be 1) to start the flow of liquid slowly to minimize turbulence and foaming as much as possible, and 2) if you're bottling beer, flushing with CO2 will reduce contact with oxygen and minimize skunking so that's not a concern for soda, unless you have hops or something else in there that could go skunky.

The next time I bottle my sparkling wine I'm going ti try inverting the keg and filling with gravity through the co2 post and sucking air in through the liquid post.. I've done many sparkling wines and ciders and force carb up to 4 volumes but feel I loose a lot when bottling. I also use the beer gun but even pushing at 3-5 psi it foams and looses lots!! Temperature is the biggest factor in trying to keep most the co2 in solution..