Blichmann QuickCarb undercarbing issue

[Datsvibe]

I’m relatively new to homebrewing and it seems that every time I brew a new batch I encounter a new issue..

Last time I used the Blichmann QuickCarb to force carb a batch- it was overcarbed and I lost 1/2 the batch to foam etc...

This time using the QuickCarb I somehow undercarbed the batch. I consulted the chart and carbed my Pumpkin Ale to 2.5 volumes.

It was late so after QuickCarb was done, I threw keg in fridge and continued first thing in the morning...

I don’t have a kegerator at the moment so I force-carb & I use a beer-gun to fill/cap the bottles.

My best guess is- the keg somehow had a c02 leak/ wasn’t airtight and lost it’s carbonation- but that just a guess...

Beginning to think the BeerGun and QuickCarb were unwise purchases as I can’t seem to use them correctly..

I have 50 bottles, capped and extremely undercarbed. I didn’t think to try a glass before I bottled because it was 6:00am and I was just glad this batch wasn’t foaming like my last batch... ugh... Dumb!

My question is - Is there any way to salvage the batch. Hoping I can pop the caps, drop a Fizz Drop in and quickly re-cap..

Wishful thinking? I hope not.

Any help or suggestion is very much appreciated!