With regards to Germany I'm not sure if I would call it a gun culture. But when my dad's unit arrived in Germany near the end of the 2nd world war, the civilians were instructed to surrender all weapons to their camp. Apprently it was quite a large pile I think a lot of the difference between Canada and the USA is our history. Not all but many early settlers fled Europe to the US for various reasons. Where as many but not all Canadian pioneers came by choice. We negotiated our original independence. The USA fought for theirs. These things have a way of being ingrained into a culture.
Much like when we were in Bosnia and were confiscating weapons, we found weapons of all makes and models from MP-40s, MG-39s, to Thompsons, Uzis and everything in between.
When a country is at war, all bets are off, one must look at the peace-time status of the country in question. Germany definitely did not pose as a gun culture before or after the wars fought, only during.
The US were fighting occupation of British troops as they did not accept colonization. The main difference is we (Canada) did, if we did not, we would have been very similar to the US (or part of them). The war of 1812 was fought between the US and British as Canada was not a formed independent country at that time as wasn't until 1867.