Gurgling can be cause by the pipe itself but, usually you'll find that it's operator error and covers several things.
Tobacco too wet, puffing to much and needing to slow down ones cadence and as you've read, weather.
Now, I think we've all puffed a little too much at one time or another depending on our surroundings and mood.
We just have to remind ourselves to take it easy and slow down. Your tobacco will taste much better also.
On another note, I would not take upon yourself to drill a pipe out for several reasons.
You can really screw it up if you're not knowledgeable about sizes of drafts and airways and using a drill motor to do it.
Also, it may not be the draft hole but, the chamber drilled too deep below the draft that is doing it which is basically unrepairable unless you want to fill the bottom of the chamber with pipe mud or the like.
Sometimes its as simple as counter sinking the tenon. So if one knows it's the pipe, they should send it to someone that knows there way around pipe repair and or the making of.
