"Also, many suppliers here don't ship internationally."
There is a reason for that. Some gun parts require a US dealer (or indeed anyone) to have a munitions export permit to ship out of the country. Some may remember the story of Ranch Products, a manufacturer of full moon clips allowing use of .45 ACP ammunition in 1917 revolvers. They got in serious trouble some years ago for shipping clips out of the country without a munitions export permit. And they weren't even gun parts.