Swingtops and tempature changes

About to blitchmann beer gun my first whole batch of beer and I have a quick question. I will be filling up swingtops and I know I will lose carbonation until the head space it filled. Will allowing the beer to warm to room temp and then bring back down to cold temps effect the carbonation. My guess is no as long as its sealed. However, wasn't sure if gas escapes when warmed then I have to wait for the beer to force carb itself once its colf again. I filled one bottle and let it sit about an hour in the fridge when I popped it carb was perfect but I wouldn't want it any less so wondering what will happen after they warm and cool.

I would refrigerate the bottles to bring them at or below the beer temps. Also put some gas in the bottles before you add the beer to help prevent oxidation.

You want to bottle at the coldest possible temperature you can. You can dissolve more gas in colder liquids. If you do everything right and in a timely manner the amount of carbonation lost should be minimal. Remember that Le Methode Champenose uncaps the finished product before corking and Champagne is one of the most carbonated beverages around.
BierMuncher has an excellent thread on using a DIY beergun but the skills apply to commercial products. The ClifNotes version is put your bottles in the freezer an hour ahead and keep theh beer cold.

Best method for using the beergun is to increase the PSI on your keg a couple days ahead of time, I assume I'll lose about 0.2 volumes during the bottling process, so I overcarb by just about that much. Definitely chill the bottles, but storing them warm or cold after bottling, shouldn't matter, as long as you chill them down before serving.